研究者詳細 - 坂倉　彰

論文 - 坂倉　彰

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Rapid construction of a diterpene-inspired tetracyclic skeleton bearing bicyclo[3.2.1]octane rings based on desymmetrization of 1,3-diketones

Hidetoshi Kamada, Haruki Mizoguchi, Akira Sakakura

Tetrahedron Letters 2025年2月

Synthesis and biological evaluation of coprinoferrin, an acylated tripeptide hydroxamate siderophore

Ichiro Hayakawa, Tomoki Isogai, Jun Takanishi, Shihori Asai, Chika Ando, Tomohiro Tsutsumi, Kenji Watanabe, Akira Sakakura, Yuta Tsunematsu

Organic & Biomolecular Chemistry 2024年

掲載種別：研究論文（学術雑誌）出版者・発行元：Royal Society of Chemistry (RSC)

Coprinoferrin (CPF), originally isolated from a genetically engineered strain (∆laeA) of mushroom fungus Coprinopsis cinerea, is an acylated tripeptide hydroxamate consisting of tandem aligned N5-hexanoyl-N5-hydroxy-L-ornithine with modifications of N-acetyl and...

DOI： 10.1039/d3ob01850d

Visible-Light-Photoexcited Palladium-Catalyzed Silylmethylation of Benzyl Alcohol Derivatives 招待査読

Haruki Mizoguchi, Akira Sakakura, Ryuji Yoshida, Haruka Ikeda

Synlett 34 ( 20 ) 2451 - 2454 2023年7月

Enantioselective construction of beta-hydroxy-alpha,alpha-disubstituted alpha-amino acid derivatives via direct aldol reaction of alpha-imino esters 査読

Yuya Araki, Masato Hanada, Yoshiko Iguchi, Haruki Mizoguchi, Akira Sakakura

TETRAHEDRON 110 2022年3月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

The beta-hydroxy-alpha,alpha-disubstituted alpha-amino acid is a valuable structural motif for research in the field of bioorganic chemistry and in the development of peptide drugs. This report describes the enantioselective direct-aldol reaction of alpha-imino esters with glyoxylate esters. We discovered that a catalytic amount of Co(OAc)(2)-pybox complex catalyzed the aldol reaction of salicylaldehyde-derived alpha-imino esters with benzyl glyoxylate in good yield and enantioselectivity. In addition, hydrolysis of the imine moiety of the aldol products followed by Boc protection of the resultant amino group gave the N-Boc-protected amino acid derivatives. (C) 2022 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2022.132695

Annulative coupling of vinylboronic esters: aryne-triggered 1,2-metallate rearrangement 査読

Haruki Mizoguchi, Hidetoshi Kamada, Kazuki Morimoto, Ryuji Yoshida, Akira Sakakura

Chemical Science 13 ( 33 ) 9580 - 9585 2022年

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Royal Society of Chemistry ({RSC})

A stereoselective annulative coupling of a vinylboronic ester ate-complex with arynes producing cyclic borinic esters has been developed. An annulation reaction that proceeded through the formation of two C-C bonds and a C-B bond was realized by exploiting a 1,2-metallate rearrangement of boronate triggered by the addition of a vinyl group to the strained triple bond of an aryne. The generated aryl anion would then cyclize to a boron atom to complete the annulation cascade. The annulated borinic ester could be converted to boronic acids and their derivatives by oxidation, halogenation, and cross-coupling. Particularly, halogenation and Suzuki-Miyaura coupling proceeded in a site-selective fashion and produced highly substituted alkylboronic acid derivatives.

DOI： 10.1039/D2SC02623F

Toward the Synthesis of Paspaline-Type Indole-Terpenes: Stereoselective Construction of Core Scaffold with Contiguous Asymmetric Quaternary Carbon Centers 査読

Ichiro Hayakawa, Naochika Matsumaru, Akira Sakakura

The Journal of Organic Chemistry 86 ( 14 ) 9802 - 9810 2021年7月

Strain-release Difunctionalization of C–C σ- and π-bonds of an Organoboron Ate-complex through 1,2-Metallate Rearrangement 招待査読

Haruki Mizoguchi, Akira Sakakura

Chemistry Letters 50 ( 4 ) 792 - 799 2021年4月

Dual Inhibition of γ-Tubulin and Plk1 Induces Mitotic Cell Death 査読

Haruna Ebisu, Kana Shintani, Takumi Chinen, Yoko Nagumo, Shuya Shioda, Taisei Hatanaka, Akira Sakakura, Ichiro Hayakawa, Hideo Kigoshi, Takeo Usui

Frontiers in Pharmacology 11 2021年1月

掲載種別：研究論文（学術雑誌）出版者・発行元：Frontiers Media SA

α/β-Tubulin inhibitors that alter microtubule (MT) dynamics are commonly used in cancer therapy, however, these inhibitors also cause severe side effects such as peripheral neuropathy. γ-Tubulin is a possible target as antitumor drugs with low side effects, but the antitumor effect of γ-tubulin inhibitors has not been reported yet. In this study, we verified the antitumor activity of gatastatin, a γ-tubulin specific inhibitor. The cytotoxicity of gatastatin was relatively weak compared with that of the conventional MT inhibitors, paclitaxel and vinblastine. To improve the cytotoxicity, we screened the chemicals that improve the effects of gatastatin and found that BI 2536, a Plk1 inhibitor, greatly increases the cytotoxicity of gatastatin. Co-treatment with gatastatin and BI 2536 arrested cell cycle progression at mitosis with abnormal spindles. Moreover, mitotic cell death induced by the combined treatment was suppressed by the Mps1 inhibitor, reversine. These findings suggest that co-treatment with Plk1 and γ-tubulin inhibitors causes spindle assembly checkpoint-dependent mitotic cell death by impairing centrosome functions. These results raise the possibility of Plk1 and γ-tubulin inhibitor co-treatment as a novel cancer chemotherapy.

DOI： 10.3389/fphar.2020.620185

Kinetic Resolution of α-Nitrolactones by Catalytic Asymmetric Hydrolysis or Ester–Amide Exchange Reaction 査読

Akira Sakakura, Ryota Nakao, Yudai Fujii, Ichiro Hayakawa, Haruki Mizoguchi

Synlett 31 ( 20 ) 2018 - 2022 2020年12月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Georg Thieme Verlag {KG}

<title>Abstract</title>
C
1-Symmetric chiral ammonium salt catalysts induced a kinetic resolution of racemic α-nitrolactones through an asymmetric ester–amide exchange reaction. The corresponding amides were obtained with high enantioselectivities and high S (= k
fast/k
slow) values. This reaction system is a useful approach for obtaining carbocyclic quaternary α-nitroamides as chiral building blocks.

DOI： 10.1055/s-0040-1707303

Enantioselective Diels–Alder Reaction of 3-Nitrocoumarins Promoted by Chiral Organoammonium Salt Catalysts 査読

Akira Sakakura, Yudai Fujii, Ryota Nakao, Saki Sugihara, Keita Fujita, Yuya Araki, Takayuki Kudoh, Ichiro Hayakawa, Haruki Mizoguchi

Synlett 31 ( 20 ) 2013 - 2017 2020年12月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Georg Thieme Verlag {KG}

<title>Abstract</title>An enantioselective Diels–Alder reaction of 3-nitrocoumarins has been developed. A tryptophan-derived C
1-symmetric organoammonium thiourea catalyst promoted the reaction of 3-nitrocoumarins with Danishefsky’s diene to give the corresponding adducts with good enantioselectivity (up to 94% ee). One of the resulting adducts was converted into a chiral carbocyclic quaternary β-amino alcohol.

DOI： 10.1055/s-0040-1707302

Structure Optimization of Gatastatin for the Development of gamma-Tubulin-Specific Inhibitor 査読

Kana Shintani, Haruna Ebisu, Minagi Mukaiyama, Taisei Hatanaka, Takumi Chinen, Daisuke Takao, Yoko Nagumo, Akira Sakakura, Ichiro Hayakawa, Takeo Usui

ACS MEDICINAL CHEMISTRY LETTERS 11 ( 6 ) 1125 - 1129 2020年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

Gatastatin (O-7-benzyl glaziovianin A) is a gamma-tubulin-specific inhibitor that is used to investigate gamma-tubulin function in cells. We have previously reported that the unsubstituted phenyl ring of the O-7-benzyl group in gatastatin is important for gamma-tubulin inhibition. To obtain further structural information regarding gamma-tubulin inhibition, we synthesized several gatastatin derivatives containing a fixed O-7-benzyl moiety. Modifications of the B-ring resulted in drastic decrease in cytotoxicity, abnormal spindle formation activity, and inhibition of microtubule (MT) nucleation. In contrast, various O-6-alkylated gatastatin derivatives showed potent cytotoxicity, induced abnormal spindle formation, and inhibited MT nucleation. We had previously reported that O-6-benzyl glaziovianin A is a potent alpha/beta-tubulin inhibitor; thus, these new results suggest that the O-6-position restricts affinity for alpha/beta- and gamma-tubulin. Considering that an O-7-benzyl group increases specificity for gamma-tubulin, more potent and specific gamma-tubulin inhibitors can be generated through O-6-modifications of gatastatin.

DOI： 10.1021/acsmedchemlett.9b00526

Formal Total Synthesis of Manzacidin B via Sequential Diastereodivergent Henry Reaction 査読

Yuya Araki, Natsumi Miyoshi, Kazuki Morimoto, Takayuki Kudoh, Haruki Mizoguchi, Akira Sakakura

JOURNAL OF ORGANIC CHEMISTRY 85 ( 2 ) 798 - 805 2020年1月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

A formal total synthesis of manzacidin B is described. beta,beta-Disubstituted gamma-hydroxy-beta-aminoalcohol, the key structure of manzacidin B, is stereoselectively constructed via sequential Henry reactions. By taking advantage of noncovalent interactions, such as intramolecular hydrogen bonding and chelation, we could diastereodivergently control the stereoselectivity of the Henry reaction.

DOI： 10.1021/acs.joc.9b02811

Synthesis of functionalized cyclopropylboronic esters based on a 1,2-metallate rearrangement of cyclopropenylboronate 査読

Haruki Mizoguchi, Masaya Seriu, Akira Sakakura

Chemical Communications 56 ( 99 ) 15545 - 15548 2020年

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Royal Society of Chemistry (RSC)

<p>A procedure converting tribromocyclopropane to densely functionalized β-selenocyclopropylboronic ester using the 1,2-metallate rearrangement of a boron ate-complex has been developed.</p>

DOI： 10.1039/d0cc07134j

Toward the Synthesis of SB-203207: Construction of Four Contiguous Nitrogen-Containing Stereogenic Centers 査読

Ichiro Hayakawa, Anna Nagayasu, Akira Sakakura

The Journal of Organic Chemistry 84 ( 23 ) 15614 - 15623 2019年12月

Enantioselective 1,3-Dipolar Cycloaddition Reaction of Nitrones with α-(Acyloxy)acroleins Catalyzed by Dipeptide-Derived Chiral Tri- or Diammonium Salts 査読

Chihiro Kidou, Haruki Mizoguchi, Tatsuo Nehira, Akira Sakakura

Synlett 30 ( 15 ) 1835 - 1839 2019年9月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Georg Thieme Verlag {KG}

Organoammonium salts of dipeptide-derived chiral triamines or diamines with TfOH catalyzed the enantioselective 1,3-dipolar cycloaddition reactions of α-acyloxyacroleins with nitrones to give the corresponding adducts in good yields (up to 96%) and with high diastereo- and enantioselectivities (up to 89% ee). Although α-(p-methoxybenzoyloxy)acrolein is rather unstable under the reaction conditions, α-(3-pyrroline-1-carbonyloxy)acrolein is stable enough to be smoothly converted into the corresponding adducts with the aid of the chiral organoammonium salt catalysts.

DOI： 10.1055/s-0039-1690133

Toward the Synthesis of Yuzurimine-Type Alkaloids: Stereoselective Construction of the Heterocyclic Portions of Deoxyyuzurimine and Macrodaphnine 査読国際誌

Ichiro Hayakawa, Ryosuke Nagatani, Masaki Ikeda, Dong-eun Yoo, Keita Saito, Hideo Kigoshi, Akira Sakakura

Organic Letters 21 ( 16 ) 6337 - 6341 2019年8月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：American Chemical Society (ACS)

The heterocyclic portions of yuzurimine-type alkaloids, such as deoxyyuzurimine and macrodaphnine, were synthesized by using a stereoselective hydroboration-oxidation reaction to install the C20 methyl group, the intramolecular Mitsunobu reaction to construct the E-ring portion, and the intramolecular SN2 reaction to construct the F-ring portion as key steps.

DOI： 10.1021/acs.orglett.9b02232

Thioureas as Highly Active Catalysts for Biomimetic Bromocyclization of Geranyl Derivatives 査読

Miyuki Terazaki, Kei-ichi Shiomoto, Haruki Mizoguchi, Akira Sakakura

Organic Letters 21 ( 7 ) 2073 - 2076 2019年4月

Catalytic enantioselective Hosomi–Sakurai reaction of α-ketoesters promoted by chiral copper(ii) complexes 査読

Yutaro Niwa, Mayu Miyake, Ichiro Hayakawa, Akira Sakakura

Chemical Communications 55 ( 27 ) 3923 - 3926 2019年

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Royal Society of Chemistry ({RSC})

<p>The first catalytic enantioselective Hosomi−Sakurai reaction of α-ketoesters.</p>

DOI： 10.1039/C9CC01159E

Chiral Pyrophosphoric Acid Catalysts for the para-Selective and Enantioselective Aza-Friedel–Crafts Reaction of Phenols 査読

Akira Sakakura, Manabu Hatano, Kazuaki Ishihara, Haruka Okamoto, Kohei Toh, Takuya Mochizuki, Hidefumi Nakatsuji

Synthesis 50 ( 23 ) 4577 - 4590 2018年12月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Georg Thieme Verlag {KG}

Chiral BINOL-derived pyrophosphoric acid catalysts were developed and used for the regio- and enantioselective aza-Friedel–Crafts reaction of phenols with aldimines. ortho/para-Directing phenols could react at the para-position selectively with moderate to good enantioselectivities. Moreover, the gram-scale transformation of a product into the key intermediate for the antifungal agent (R)-bifonazole was demonstrated.

DOI： 10.1055/s-0037-1610250

Enantioselective aza-Friedel–Crafts reaction of furan with α-ketimino esters induced by a conjugated double hydrogen bond network of chiral bis(phosphoric acid) catalysts 査読

Manabu Hatano, Haruka Okamoto, Taro Kawakami, Kohei Toh, Hidefumi Nakatsuji, Akira Sakakura, Kazuaki Ishihara

Chemical Science 9 ( 30 ) 6361 - 6367 2018年

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Royal Society of Chemistry ({RSC})

<p>Chiral <italic>C</italic>₂- and <italic>C</italic>₁-symmetric BINOL-derived bis(phosphoric acid) catalysts facilitated the enantioselective aza-Friedel–Crafts reaction of 2-methoxyfuran with α-ketimino esters.</p>

DOI： 10.1039/C8SC02290A

Regioselective DMAD-insertion reaction of silyl dienol ether of γ-pyrone under catalyst- and heating-free conditions 査読

Ichiro Hayakawa, Yuji Yamanaka, Koichi Mitsudo, Hiromi Ota, Akira Sakakura

Heterocycles 94 ( 12 ) 2299 - 2306 2017年12月

Diastereodivergent Henry Reaction for the Stereoselective Construction of Nitrogen-Containing Tetrasubstituted Carbons: Application to Total Synthesis of Manzacidins A and C 査読

Takayuki Kudoh, Yuya Araki, Natsumi Miyoshi, Mizuho Tanioka, Akira Sakakura

ASIAN JOURNAL OF ORGANIC CHEMISTRY 6 ( 12 ) 1760 - 1763 2017年12月

担当区分：最終著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-V C H VERLAG GMBH

beta,beta,-Disubstituted -amino alcohols has been synthesized in a diastereodivergent manner from chiral secondary nitroalkanes as starting materials. In this key Henry reaction, the use of different protecting groups resulted in the diastereoselective construction of the tetrasubstituted carbon stereocenter with different configuration. Based on this methodology, a total synthesis of manzacidins A and C has been achieved.

DOI： 10.1002/ajoc.201700568

Heat Versus Basic Conditions: Intramolecular Dehydro-Diels–Alder Reaction of 1-Indolyl-1,6-heptadiynes for the Selective Synthesis of Substituted Carbazoles 査読

Takayuki Kudoh, Syo Fujisawa, Megumi Kitamura, Akira Sakakura

Synlett 28 ( 16 ) 2189 - 2193 2017年10月

Reinvestigation of the Biomimetic Cyclization of 3,5-Diketoesters: Application to the Total Synthesis of Cyercene A, an α-Methoxy-γ-Pyrone-Containing Polypropionate 査読

Kai Onda, Ichiro Hayakawa, Akira Sakakura

Synlett 28 ( 13 ) 1596 - 1600 2017年8月

Discovery of O6-benzyl glaziovianin A, a potent cytotoxic substance and a potent inhibitor of α,β-tubulin polymerization 査読

Ichiro Hayakawa, Shuya Shioda, Takumi Chinen, Taisei Hatanaka, Haruna Ebisu, Akira Sakakura, Takeo Usui, Hideo Kigoshi

Bioorganic and Medicinal Chemistry 24 ( 21 ) 5639 - 5645 2016年11月

A short access to 3,5-disubstituted piperazinones based on the aza-Michael addition of α-amino esters to β-substituted nitroalkenes 査読

Takayuki Kudoh, Seiji Isoyama, Sachiko Kagimoto, Katsutoshi Kurihara, Akira Sakakura

Tetrahedron Letters 57 ( 42 ) 4693 - 4696 2016年10月

Enantioselective bromocyclization of 2-geranylphenols induced by chiral phosphite-urea bifunctional catalysts 査読

Yasuhiro Sawamura, Yoshihiro Ogura, Hidefumi Nakatsuji, Akira Sakakura, Kazuaki Ishihara

CHEMICAL COMMUNICATIONS 52 ( 36 ) 6068 - 6071 2016年

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

Chiral phosphite-urea bifunctional catalysts have been developed for the enantioselective bromocyclization of 2-geranylphenols with N-bromophthalimide (NBP) for the first time. The chiral triaryl phosphite moiety activates NBP to generate a bromophosphonium ion. On the other hand, the urea moiety interacts with a hydroxyl group of the substrate through hydrogen bonding interactions. Enantioselectivity is effectively induced through two-point attractive interactions between the catalyst and the substrate.

DOI： 10.1039/c6cc00229c

Stereoselective Electrophilic Cyclization 査読

Akira Sakakura, Kazuaki Ishihara

CHEMICAL RECORD 15 ( 4 ) 728 - 742 2015年8月

担当区分：筆頭著者,　責任著者記述言語：英語出版者・発行元：WILEY-V C H VERLAG GMBH

Electrophilic cyclizations of unactivated alkenes play highly important roles in the synthesis of useful building blocks. This account describes our contributions to the rational design of monofunctionalized chiral Lewis base catalysts for enantioselective iodo- and protocyclizations. For the stereoselective promotion of electrophilic bromocyclizations, nucleophilic phosphite-urea cooperative catalysts have been designed.

DOI： 10.1002/tcr.201500005

Enantioselective 1,3-Dipolar Cycloaddition of Azomethine Imines with Propioloylpyrazoles Induced by Chiral π-Cation Catalysts 査読

Masahiro Hori, Akira Sakakura, Kazuaki Ishihara

Journal of the American Chemical Society 136 ( 38 ) 13198 - 13201 2014年9月

Selective Bromocyclization of 2-Geranylphenols Promoted by Phosphite-Urea Cooperative Catalysts 査読

Yasuhiro Sawamura, Hidefumi Nakatsuji, Matsujiro Akakura, Akira Sakakura, Kazuaki Ishihara

CHIRALITY 26 ( 7 ) 356 - 360 2014年7月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-BLACKWELL

Nucleophilic phosphite-urea cooperative catalysts are highly efficient for the bromonium-induced cyclization of 2-geranylphenols. Phosphite-N,N'-dimethylurea catalysts also show moderate activity, probably due to the steric effect of their bent conformation. Chirality 26:355-359, 2014. (c) 2014 Wiley Periodicals, Inc.

DOI： 10.1002/chir.22297

Cooperative Activation with Chiral Nucleophilic Catalysts and N-Haloimides: Enantioselective Iodolactonization of 4-Arylmethyl-4-pentenoic Acids 査読

Hidefumi Nakatsuji, Yasuhiro Sawamura, Akira Sakakura, Kazuaki Ishihara

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 53 ( 27 ) 6974 - 6977 2014年7月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-V C H VERLAG GMBH

Chiral triaryl phosphates promote the enantioselective iodolactonization of 4-substituted 4-pentenoic acids to give the corresponding iodolactones in high yields with high enantioselectivity. N-Chlorophthalimide (NCP) is employed as a Lewis acidic activator and oxidant of I-2 for the present iodolactonization. In combination with 1.5 equivalents of NCP, only 0.5 equivalents of I-2 are sufficient to generate the iodinating reagent.

DOI： 10.1002/anie.201400946

Catalytic Enantioselective Inverse Electron Demand Hetero-Diels-Alder Reaction with Allylsilanes 査読

Yuki Matsumura, Takahiro Suzuki, Akira Sakakura, Kazuaki Ishihara

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 53 ( 24 ) 6131 - 6134 2014年6月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-V C H VERLAG GMBH

The first diastereo- and enantioselective inverse electron demand hetero-Diels-Alder reaction of beta,gamma-unsaturated alpha-ketoesters with allylsilanes is described. Chiral copper( II) catalysts successfully activate the beta,gamma-unsaturated alpha-ketoesters and promote the reaction with allylsilanes with excellent enantioselectivities. This process represents a new entry to chiral oxanes.

DOI： 10.1002/anie.201402934

Enantioselective Cyanoethoxycarbonylation of Isatins Promoted by a Lewis Base–Brønsted Acid Cooperative Catalyst 査読

Yoshihiro Ogura, Matsujiro Akakura, Akira Sakakura, Kazuaki Ishihara

Angewandte Chemie International Edition 52 ( 32 ) 8299 - 8303 2013年8月

Primary Alkylboronic Acids as Highly Active Catalysts for the Dehydrative Amide Condensation of α-Hydroxycarboxylic Acids 査読

Risa Yamashita, Akira Sakakura, Kazuaki Ishihara

Organic Letters 15 ( 14 ) 3654 - 3657 2013年7月

Kinetic Resolution of Racemic Carboxylic Acids through Asymmetric Protolactonization Promoted by Chiral Phosphonous Acid Diester 査読

Masayuki Sakuma, Akira Sakakura, Kazuaki Ishihara

ORGANIC LETTERS 15 ( 11 ) 2838 - 2841 2013年6月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

Chiral phosphonium salts induce the kinetic resolution of racemic a-substituted unsaturated carboxylic acids through asymmetric protolactonization. Both the lactones and the recovered carboxylic acids are obtained with high enantioselectivities and high S (=k(fast)/k(slow)) values. Asymmetric protolactonization also leads to the desymmetrization of achiral carboxylic acids. Notably, chiral phosphonous acid diester not only induced the enantioselectivity but also promoted protolactonization.

DOI： 10.1021/ol401313d

“Phosphite–Urea” Cooperative High-Turnover Catalysts for the Highly Selective Bromocyclization of Homogeranylarenes 査読

Yasuhiro Sawamura, Hidefumi Nakatsuji, Akira Sakakura, Kazuaki Ishihara

Chemical Science 4 ( 11 ) 4181 - 4186 2013年

α-Heterosubstituted β-Alkylacroleins as Useful Multisubstituted Dienophiles for Enantioselective Diels-Alder Reactions 査読

Akira Sakakura, Hiroki Yamada, Kazuaki Ishihara

Asian Journal of Organic Chemistry 1 ( 2 ) 133 - 137 2012年10月

Enantioselective Diels–Alder Reaction of α-(Acylthio)acroleins: a New Entry to Sulfur-containing Chiral Quaternary Carbons 査読

Akira Sakakura, Hiroki Yamada, Kazuaki Ishihara

Organic Letters 14 ( 12 ) 2972 - 2975 2012年6月

N,N-Diarylammonium Pyrosulfate as a Highly Effective Reverse Micelle-Type Catalyst for Hydrolysis of Esters 査読

Yoshiki Koshikari, Akira Sakakura, Kazuaki Ishihara

ORGANIC LETTERS 14 ( 12 ) 3194 - 3197 2012年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

Reverse micelle-type N,N-diarylammonium pyrosulfate (3-5 mol %) efficiently catalyzes the hydrolysis of esters (up to 100 mmol scale) under organic solvent-free conditions. The present method is successfully applied to the hydrolysis of various esters without the decomposition of the base-sensitive moieties and without any loss of optical purity for alpha-heterosubstituted carboxylic acids.

DOI： 10.1021/ol301290c

Hydrophobic N,N-Diarylammonium Pyrosulfates as Dehydrative Condensation Catalysts under Aqueous Conditions 査読

Akira Sakakura, Yoshiki Koshikari, Matsujiro Akakura, Kazuaki Ishihara

ORGANIC LETTERS 14 ( 1 ) 30 - 33 2012年1月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

Oil-soluble N,N-diarylammonium pyrosulfates as nonsurfactant-type catalysts for the dehydrative ester condensation under aqueous conditions are described. Preheat treatment of dibasic sulfuric acid with bulky N,N-diarylamines generates water-tolerant salts of pyrosulfuric acid as active catalyst species. The present catalysts in water can also widely be applied to unusual selective esterifications and dehydrative glycosylation.

DOI： 10.1021/ol2027366

Aplyronines D–H from the sea hare Aplysia kurodai: isolation, structures, and cytotoxicity 査読

Makoto Ojika, Hideo Kigoshi, Kiyotake Suenaga, Yoshifumi Imamura, Kohji Yoshikawa, Takeshi Ishigaki, Akira Sakakura, Tsuyoshi Mutou, Kiyoyuki Yamada

Tetrahedron 68 ( 4 ) 982 - 987 2012年1月

Desymmetrization of meso-Glycerol Derivatives Induced by L-Histidine-Derived Acylation Catalysts 査読

Akira Sakakura, Shuhei Umemura, Kazuaki Ishihara

ADVANCED SYNTHESIS & CATALYSIS 353 ( 11-12 ) 1938 - 1942 2011年8月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-V C H VERLAG GMBH

The desymmetrization of meso-glycerol derivatives bearing a 3-pyrroline-1-carbonyl (Pyroc) directing group is demonstrated through an enantioselective acylation reaction promoted by L-histidine-derived bifunctional catalysts. The desired monoacylated products are obtained in good yields (up to 74%) with high enantioselectivities (up to 99% ee).

DOI： 10.1002/adsc.201100252

Chiral Lewis Base-Assisted Brønsted Acid (LBBA)-Catalyzed Enantioselective Cyclization of 2-Geranylphenols 査読

Akira Sakakura, Masayuki Sakuma, Kazuaki Ishihara

Organic Letters 13 ( 12 ) 3130 - 3133 2011年6月

Brønsted Base-Assisted Boronic Acid Catalysis for the Dehydrative Intramolecular Condensation of Dicarboxylic Acids 査読

Akira Sakakura, Takuro Ohkubo, Risa Yamashita, Matsujiro Akakura, Kazuaki Ishihara

Organic Letters 13 ( 5 ) 892 - 895 2011年3月

Intramolecular Dehydrative Condensation of Dicarboxylic Acids with Brønsted Base-Assisted Boronic Acid Catalysts 査読

Akira Sakakura, Risa Yamashita, Takuro Ohkubo, Matsujiro Akakura, Kazuaki Ishihara

Australian Journal of Chemistry 64 ( 11 ) 1458 - 1465 2011年

Asymmetric Cu(II) catalyses for cycloaddition reactions based on π–cation or n–cation interaction 査読

Akira Sakakura, Kazuaki Ishihara

Chemical Society Reviews 40 ( 1 ) 163 - 172 2011年

Nucleophilic Phosphine–Catalyzed Iodocyclization of Isoprenoids Bearing an Oxygen Terminal Group 査読

Akira Sakakura, Gakujun Shomi, Atsushi Ukai, Kazuaki Ishihara

Heterocycles 82 ( 1 ) 249 - 255 2010年12月

Catalytic Enantioselective 1,3-Dipolar Cycloadditions of Nitrones with Propioloylpyrazoles and Acryloylpyrazoles Induced by Chiral π–Cation Catalysts 査読

Akira Sakakura, Masahiro Hori, Makoto Fushimi, Kazuaki Ishihara

Journal of the American Chemical Society 132 ( 44 ) 15550 - 15552 2010年11月

ChemInform Abstract: Jolkinolide D Pharmacophore: Synthesis and Reaction with Amino Acids, Nucleosides, and DNA.

Akira Sakakura, Yui Takayanagi, Hideo Kigoshi

ChemInform 33 ( 46 ) no - no 2010年5月

Organoammonium Salt-Catalyzed Enantioselective Cycloaddition Reactions with α-(Acyloxy)- or α-Diacylaminoacroleins 査読

Akira Sakakura, Kazuaki Ishihara

Bulletin of the Chemical Society of Japan 83 ( 4 ) 313 - 322 2010年4月

Rational Design of Highly Effective Asymmetric Diels-Alder Catalysts Bearing 4,4 '-Sulfonamidomethyl Groups 査読

Akira Sakakura, Rei Kondo, Yuki Matsumura, Matsujiro Akakura, Kazuaki Ishihara

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 131 ( 49 ) 17762 - 17764 2009年12月

3-Pyrroline-1-carbonyl (Pyroc) Group: A Removable Protecting Group for the Kinetic Resolution of Racemic Carboxylic Acids and Alcohols through Catalytic Asymmetric Acylation 査読

Akira Sakakura, Shuhei Umemura, Kazuaki Ishihara

SYNLETT ( 10 ) 1647 - 1650 2009年6月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：GEORG THIEME VERLAG KG

The O-3-pyrroline-1-carbonyl (O-Pyroc) group and 3-pyrrolinamide are useful removable protecting groups for the kinetic resolution of racemic alpha-hydroxycarboxylic acids, beta-hydroxycarboxylic acids, 1,2-dicarboxylic acids, and 1,2-diols using the L-histidine-derived bifunctional catalysts. The Pyroc group can be easily introduced from Pyroc chloride. Selective deprotection of the Pyroc group and 3-pyrrolinamide can be carried out via DDQ oxidation followed by hydrolysis using sodium hydroxide, without epimerization.

DOI： 10.1055/s-0029-1217321

Dehydrative cyclization of serine, threonine, and cysteine residues catalyzed by molybdenum(VI) oxo compounds 査読

Akira Sakakura, Rei Kondo, Shuhei Umemura, Kazuaki Ishihara

TETRAHEDRON 65 ( 10 ) 2102 - 2109 2009年3月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

Commercially available molybdenum(VI) oxides such as (NH4)(2)MoO4, (NH4)(6)Mo7O24 center dot 4H(2)O, MoO2(acac)(2), and MoO2(TMHD)(2) are highly effective dehydrative cyclization catalysts for the synthesis of a variety of oxazolines. The reaction proceeds with a complete retention of configuration at the beta-position. For the dehydrative cyclization of cysteine derivatives, bis(2-ethyl-8-quinolinolato)dioxomolybdenum(VI) shows remarkable catalytic activity and gives thiazolines without a significant loss of stereochemical integrity at the C2-exomethine positions. (C) 2008 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2008.12.074

Design of High-Performance Catalysts Based on Acid-Base Combined Salts and Development of Highly Selective Reactions 査読

Akira Sakakura

JOURNAL OF SYNTHETIC ORGANIC CHEMISTRY JAPAN 66 ( 10 ) 942 - 952 2008年10月

担当区分：責任著者記述言語：日本語出版者・発行元：SOC SYNTHETIC ORGANIC CHEM JPN

The design of highly functionalized artificial catalysts is very important for practical organic synthesis. We have succeeded in the rational design of high-performance catalysts based on acid-base combined salts. Acid-base combined salt catalysts can be classified into three types: (1) Metal oxide-Lewis base combined salts, (2) Bronsted acid-Bronsted base combined salts, and (3) Lewis acid-Lewis base combined salts. Here we report our recent studies on development of highly selective cyclization reactions for the synthesis of key intermediates of bioactive natural products. Molybdenum(VI) oxide-bis(quinolinolato) complexes (class 1) efficiently catalyze biomimetic dehydrative cyclization of serine, threonine and cysteine derivatives to give oxazolines and thiazolines. Chiral 1,1'-binaphthyl-2,2'-diammonium salts (class 2) are useful catalysts for enantioselective Diels-Alder reaction of alpha-acyloxyacroleins. We also have developed the first enantioselective biomimetic iodocyclization of isoprenoids using a chiral nucleophilic promoter (class 3).

DOI： 10.5059/yukigoseikyokaishi.66.942

SELECTIVE SYNTHESIS OF CYCLIC PHOSPHORIC ACID DIESTERS THROUGH OXORHENIUM(VII)-CATALYZED DEHYDRATIVE CONDENSATION OF PHOSPHORIC ACID WITH ALCOHOLS 査読

Akira Sakakura, Masayuki Sakuma, Mikimoto Katsukawa, Kazuaki Ishihara

HETEROCYCLES 76 ( 1 ) 657 - 665 2008年9月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

The selective synthesis of phosphoric acid diesters has been achieved through the direct catalytic dehydrative condensation of phosphoric acid with two equivalents of alcohols. The present method works especially well for the synthesis of cyclic phosphoric acid diesters. The combination of perrhenic acid and N-methylbenzylamine efficiently catalyzes the dehydrative condensation of phosphoric acid with equimolar amounts of diols to give cyclic phosphoric acid diesters in excellent yields.

Kinetic resolution of racemic carboxylic acids by an L-histidine-derived sulfonamide-induced enantioselective esterification reaction 査読

Kazuaki Ishihara, Yuji Kosugi, Shuhei Umemura, Akira Sakakura

ORGANIC LETTERS 10 ( 15 ) 3191 - 3194 2008年8月

担当区分：最終著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

The direct and catalytic kinetic resolution of racemic carboxylic acids bearing a Bronsted base such as O-protected alpha-hydroxy carboxylic acids and N-protected alpha-amino acids has been accomplished through an L-histidine-derived sulfonamide-induced enantioselective esterification reaction with tert-butyl alcohol for the first time. Highly asymmetric induction [S(k(fast)/k(slow)) = up to 56] has been achieved under the equilibrium between a chiral catalyst and two diastereomeric acylammonium salts through an intramolecular hydrogen-bonding interaction.

DOI： 10.1021/ol801007m

Open-air and solvent-free ester condensation catalyzed by sulfonic acids 査読

Akira Sakakura, Yoshiki Koshikari, Kazuaki Ishihara

TETRAHEDRON LETTERS 49 ( 34 ) 5017 - 5020 2008年8月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

Ester condensation is one among the most fundamental organic transformations, and more environmentally benign alternatives to current esterification processes are needed. Under solvent-free and drying agent-free conditions, catalytic amounts of sulfonic acids promote ester condensation between an equimolar mixture of carboxylic acids and alcohols. In particular, p-toluenesulfonic acid (TsOH) and 10-camphorsulfonic acid (CSA), which have appropriate acidities, efficiently catalyze the ester condensation of secondary alcohols without their decomposition. Since the present protocol does not require solvents under simple open-air conditions, a large amount of esters can be synthesized in a rather small apparatus. (c) 2008 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2008.06.058

Rate-accelerating effect by the neighboring-group participation of protecting groups in the dehydrative cyclization of 1,3,5-triketones 査読

Akira Sakakura, Hitoshi Watanabe, Kazuaki Ishihara

ORGANIC LETTERS 10 ( 12 ) 2569 - 2572 2008年6月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

Neighboring-group participation of an acyl protecting group efficiently promotes the Bronsted acid-catalyzed dehydrative cyclization of 1,3,5-triketones to gamma-pyrones, whereas a bulky silyloxy group in the beta-position retards the cyclization. This reaction provides an efficient synthetic route for a common intermediate for the synthesis of gamma-pyrone-containing bioactive natural products.

DOI： 10.1021/ol800860p

Convergent total syntheses of fluvibactin and vibriobactin using molybdenum(VI) oxide-catalyzed dehydrative cyclization as a key step 査読

Akira Sakakura, Shuhei Umemura, Kazuaki Ishihara

CHEMICAL COMMUNICATIONS ( 30 ) 3561 - 3563 2008年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

Efficient total syntheses of fluvibactin and vibriobactin have been achieved via molybdenum(VI) oxide-catalyzed dehydrative cyclization, Sb(OEt)(3)-catalyzed ester-amide transformation, and WSCI and HOAt-promoted dehydrative amide formation.

DOI： 10.1039/b805880f

Widely useful DMAP-catalyzed esterification under auxiliary base- and solvent-free conditions 査読

Akira Sakakura, Kirnio Kawajiri, Takuro Ohkubo, Yuji Kosugi, Kazuaki Ishihara

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 129 ( 47 ) 14775 - 14779 2007年11月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

With regard to atom economy and E-factor, catalytic condensation of carboxylic acids with equimolar amounts of alcohols is the most desirable. Although several highly active dehydration catalysts have been reported, more efficient alternatives are still strongly needed because the dehydrative esterification of tertiary alcohols, phenols, acid-sensitive alcohols, amino acids, and hardly soluble alcohols has never proceeded satisfactorily. Here we report new insights into the classical DMAP-catalyzed acylation of alcohols: surprisingly, only a 0.05-2 mol % of DMAP can efficiently promote acylation of alcohols with acid anhydrides under auxiliary base- and solvent-free conditions to give the corresponding esters in high yields. Furthermore, we achieved the recovery and reuse of Commercially available polystyrene-supported DMAP without using any solvents. These serendipitous findings provide widely useful and environmentally benign esterification methods, which might be more practical and reliable than catalytic dehydrative condensation methods, in particular, for the less reactive alcohols which hardly condense with carboxylic acid directly.

DOI： 10.1021/ja075824w

Enantioselective biomimetic polyene cyclization of polyprenoids - Long-sought enantioselective reaction induced by a "chiral halonium ion" 査読

Akira Sakakura, Kazuaki Ishihara

CHIMICA OGGI-CHEMISTRY TODAY 25 ( 5 ) 9 - 12 2007年9月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：TEKNOSCIENZE PUBL

Enantioselective biomimetic polyene cyclizations of polyprenoids have been studied for a long time. Very recently, we have developed the first "chiral iodonium ion"-induced enantioselective polyene cyclization of polyprenoids using a nucleophilic promoter. Achiral nucleophilic phosphorus compounds catalytically promote the diastereoselective halocyclization in dichloromethane to give a halogenated cyclic product in excellent yield. Moreover, chiral phosphoramidites stoichiometrically promote the enantioselective halocyclization of simple polyprenoids with N-iodosuccinimide in toluene to give iodinated cyclic products in up to 99 percent ee and 99 percent ds. Some enantioselective polycyclizations have been reported in addition to this halocyclization. One of the advantages of these biomimetic polycyclizations is the simultaneous formation of several carbon-carbon bonds with the relative and absolute stereocontrol. Enantioselective biomimetic domino reactions would be highly useful for the practical synthesis of natural products and related compounds.

Catalytic synthesis of peptide-derived thiazolines and oxazolines using Bis(quinolinolato)dioxomolybdenum(VI) complexes 査読

Akira Sakakura, Rei Kondo, Shuhei Umemura, Kazuaki Ishihara

ADVANCED SYNTHESIS & CATALYSIS 349 ( 10 ) 1641 - 1646 2007年7月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-V C H VERLAG GMBH

Bis(2-ethyl-8-quinolinolato)dioxomolybdenum(VI) (9) (1 mol%) shows remarkable catalytic activity for the dehydrative cyclization of cysteine-containing dipeptides 1 to give the corresponding thiazolines 2 with less than 6% epimerization at the C2-exomethine position. For the dehydrative cyclization of threonine-containing dipeptides 4, 1 mol% of bis(2-phenyl-8-quinolinolato)dioxomolybdenum(VI) (10) gives the corresponding oxazolines 5 with retention of configuration at the 5-position.

DOI： 10.1002/adsc.200700068

Dehydrative cyclization catalyzed by the combination of molybdenum(VI) oxides and benzoic acids: First synthesis of the antitumour substance BE-70016 査読

Akira Sakakura, Shuhei Umemura, Rei Kondo, Kazuaki Ishihara

ADVANCED SYNTHESIS & CATALYSIS 349 ( 4-5 ) 551 - 555 2007年3月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-V C H VERLAG GMBH

The dehydrative cyclization of N-(o-hydroxybenzoyl)threonine derivative la is efficiently promoted by the combined use of molybdenum(VI) oxides and benzoic acids bearing electron-withdrawing substituents. In the presence of ammonium molybdate [(NH4)(2)MoO4, 10 mol %] and pentafluorobenzoic acid (C6F5CO2H; 10 mol %), dehydrative cyclization of la was conducted in toluene under azeotropic reflux conditions to give 2-(o-hydroxyphenyl)oxazoline 2a in 76 % yield. Furthermore, the first total synthesis of the antitumour substance BE-70016 was achieved using the catalytic dehydrative cyclization of la as a key reaction.

DOI： 10.1002/adsc.200600550

Design of highly functional small-molecule catalysts and related reactions based on acid-base combination chemistry 査読

Kazuaki Ishihara, Akira Sakakura, Manabu Hatano

SYNLETT ( 5 ) 686 - 703 2007年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：GEORG THIEME VERLAG KG

The design of small but highly functional artificial catalysts is very important for practical organic synthesis. We have succeeded in the rational design of small and simple catalysts and related reactions based on acid-base combination chemistry. Acid-base combined catalysts can be classified into three types: (i) acid-base combined salt catalysts, (ii) conjugate acid-base catalysts, and (iii) nonconjugate acid-base catalysts. We have systematically developed acid-base combined salt catalysts such as ammonium salts, ate complexes, ion pairs and cation-pi complexes, acid-base conjugate catalysts such as metal oxides (monoconjugation) and zinc(Il)3,3'-diphosphinol-BINOLates (triconjugation), and acid-base nonconjugate catalysts like L-histidine-derived sulfonamides.

DOI： 10.1055/s-2007-970776

Enantioselective halocyclization of polyprenoids induced by nucleophilic phosphoramidites 査読

Akira Sakakura, Atsushi Ukai, Kazuaki Ishihara

NATURE 445 ( 7130 ) 900 - 903 2007年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：NATURE PUBLISHING GROUP

Polycyclic bio-active natural products that contain halogen atoms have been isolated from a number of different marine organisms(1). The biosynthesis of these natural products appears to be initiated by an electrophilic halogenation reaction at a carbon - carbon double bond(2-4) via a mechanism that is similar to a proton-induced olefin polycyclization(5-8). Enzymes such as haloperoxidases generate an electrophilic halonium ion ( or its equivalent), which reacts with the terminal carbon - carbon double bond of the polyprenoid, enantioselectively inducing a cyclization reaction that produces a halogenated polycyclic terpenoid. Use of an enantioselective halocyclization reaction is one possible way to chemically synthesize these halogenated cyclic terpenoids; although several brominated cyclic terpenoids have been synthesized via a diastereoselective halocyclization reaction that uses stoichiometric quantities of a brominating reagent(9-12), the enantioselective halocyclization of isoprenoids induced by a chiral promoter has not yet been reported. Here we report the enantioselective halocyclization of simple polyprenoids using a nucleophilic promoter. Achiral nucleophilic phosphorus compounds are able to promote the diastereoselective halocyclization reaction to give a halogenated cyclic product in excellent yields. Moreover, chiral phosphoramidites promote the enantioselective halocyclization of simple polyprenoids with N-iodosuccinimide to give iodinated cyclic products in up to 99% enantiomeric excess and diastereomeric excess. To the best of our knowledge, this is the first successful example of the enantioselective halopolycyclization of polyprenoids.

DOI： 10.1038/nature05553

Unusual rate acceleration in bronsted acid catalyzed dehydration reactions: Local hydrophobic environment in aggregated N-(2,6-diphenylphenyl)-N-mesitylammonium pentafluorobenzenesulfonates 査読

Akira Sakakura, Hitoshi Watanabe, Shoko Nakagawa, Kazuaki Ishihara

CHEMISTRY-AN ASIAN JOURNAL 2 ( 4 ) 477 - 483 2007年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-V C H VERLAG GMBH

Bulky diarylammonium pentafluorobenzenesulfonates effectively promote dehydration reactions, such as condensation reactions to give esters and the dehydrative cyclization of 1,3.5-triketones. In particular, N-(2,6-diphenylphenyl)-N-mesitylammonium pentafluorobenzenesulfonate shows much higher catalytic activity than C6F5SO3H under reaction conditions without the removal of generated water, even though the former is a weaker acid. Its crystallization gives an aggregated cyclic ion pair, which is composed of two diarylammonium cations, four pentafluorobenzenesulfonate anions, and two oxonium cations. This ion pair is strongly stabilized by four intermolecular and two intramolecular pi-pi attractive interactions and 10 hydrogen bonds. The extremely high catalytic activity of N-(2,6-diphenylphenyl)-N-mesitylammonium pentafluorobenzenesulfonate in the dehydration reactions may be ascribed to the local hydrophobic environment of the tightly aggregated ammonium salts.

DOI： 10.1002/asia.200600380

The oxorhenium(VII)-catalyzed direct condensation of phosphoric acid with an alcohol 査読

Akira Sakakura, Mikimoto Katsukawa, Kazuaki Ishihara

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 46 ( 9 ) 1423 - 1426 2007年

Direct ester condensation catalyzed by bulky diarylammonium pentafluorobenzenesulfonates 査読

Akira Sakakura, Shoko Nakagawa, Kazuaki Ishihara

NATURE PROTOCOLS 2 ( 7 ) 1746 - 1751 2007年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：NATURE PUBLISHING GROUP

A protocol for ester condensation between equimolar amounts of carboxylic acids and alcohols catalyzed by bulky diarylammonium pentafluorobenzenesulfonate is described. We also present procedures for the synthesis of N-(2,6-diisopropylphenyl)-N-mesitylammonium pentafluorobenzenesulfonate. The present ester condensation proceeds well under mild conditions even without the removal of generated water. The synthesis of N-(2,6-diisopropylphenyl)-N-mesitylammonium pentafluorobenzenesulfonate will take similar to 5 days. The ester condensation reactions will take similar to 6 h to 3 days.

DOI： 10.1038/nprot.2007.254

Bulky phosphazenium cation catalysis for dehydrative condensation of phosphoric acid with alcohols 査読

Akira Sakakura, Mikimoto Katsukawa, Takaomi Hayashi, Kazuaki Ishihara

GREEN CHEMISTRY 9 ( 11 ) 1166 - 1169 2007年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

A metal-free phosphazenium cation-catalyzed direct dehydrative condensation of phosphoric acid with alcohols has been developed for the environmentally benign synthesis of phosphoric acid monoesters.

DOI： 10.1039/b707974e

Enantioselective Diels-Alder reaction of alpha-acyloxyacroleins catalyzed by chiral 1,1 '-binaphthyl-2,2 '-diammonium salts 査読

Akira Sakakura, Kenji Suzuki, Kazuaki Ishihara

ADVANCED SYNTHESIS & CATALYSIS 348 ( 16-17 ) 2457 - 2465 2006年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-V C H VERLAG GMBH

A diammonium salt of chiral 1,1'-binaphthyl-2,2'-diamine (2a) and trifluoromethanesulfonimide (Tf2NH) shows excellent catalytic activity and enantioselectivity for the Diels-Alder reaction of alpha-acyl-oxyacroleins. For example, in the presence of 5 mol % of 2a and 9.5 mol % of Tf2NH, the Diels-Alder reaction of alpha-(cyclohexanecarbonyloxy)acrolein with cyclopentadiene proceeded in EtCN at -75 degrees C to give the adducts in 88 % yield with 92 % exo and 91 % ee. The electron-donating property of the acyl group of the alpha-acyloxyacroleins increases the enantioselectivity due to the formation of strong intramolecular hydrogen bonding of the acyl group with a proton of the ammonium group in the transition state. This catalyst can be easily prepared in situ by mixing the commercially available chiral diamine and Tf2NH.

DOI： 10.1002/adsc.200600322

35 細胞毒性マクロリド配糖体、オーリサイド類の合成(口頭発表の部)

末永聖武, 星野紘史, 好井孝典, 森和規, 曽根大紀, 別所祐紀, 坂倉彰, 早川一郎, 山田靜之, 木越英夫

天然有機化合物討論会講演要旨集 ( 48 ) 205 - 210 2006年9月

記述言語：日本語出版者・発行元：天然有機化合物討論会

Aurisides A (1) and B (2) are macrolide glycosides isolated from Japanese sea hare Dolabella auricuralia, which exhibit cytotoxicity against HeLa S_3 cells with IC_<50> values of 0.17 and 1.2μg/mL, respectively. The main structural features of aurisides are a bromine-substituted conjugated diene, a 14-membered lactone, and a cyclic hemiacetal. We achieved the enantioselective synthesis of aurisides A and B by a convergent approach. The C1-C9 segment 4 was prepared from (R)-pantolactone using a reaction of dithiane carbanion with epoxide, stereoselective reduction of β-hydroxyketone with Me_4NBHOAc, and rhodium-catalyzed Reformatsky-type reaction as key steps. The C10-C17 segment 12 was synthesized from (R)-glycidyl trityl ether. The Nozaki-Hiyama-Kishi reaction between 4 and 12 and subsequent reactions including construction of bromine-substituted conjugated diene gave seco acid 10, which was converted into the aglycon (3) of aurisides by construction of the 14-membered lactone. The Mukaiyama glycosylation reaction of the aglycon 3 provided aurisides A (1) and B (2).

DOI： 10.24496/tennenyuki.48.0_205

8 海洋産抗腫瘍性化合物アプリロニンAの抗腫瘍機序(口頭発表の部)

黒田武史, 末永聖武, 半田知久, 宮沙織, 岡本和人, 兼松憲吾, 坂倉彰, 山田靜之, 平田邦生, 高田昌樹, 加藤健一, 村岡真, 山本雅貴, 田中宏志, 木越英夫

天然有機化合物討論会講演要旨集 ( 48 ) 43 - 48 2006年9月

記述言語：日本語出版者・発行元：天然有機化合物討論会

The interaction between actin and aplyronine A, a potent antitumor and actin-depolymerizing substance of marine origin, was investigated by photoaffinity labeling experiments and X-ray structure analysis of actin complex with aplyronine A. Photoaffinity probes consisting of a side-chain portion of aplyronine A as a ligand, a diazirine moiety as a photoaffinity group, and a fluorophor as a detecting group were synthesized. Photolabeling experiments between actin and the probe were carried out. Actin was successfully photolabeled by the fluorescent probe and visualized clearly. The present results provide the first chemical evidence for the direct interaction between actin and the side-chain portion of aplyronine A. X-ray structure analysis of actin-aplyronine A complex was carried out. The analysis showed that Aplyronine A bound to a hydrophobic cleft between subdomains 1 and 3 of actin. The structural feature is that the trimethylserine moiety protrudes toward the bulk solvent region.

DOI： 10.24496/tennenyuki.48.0_43

Enantioselective synthesis of aurisides A and B, cytotoxic macrolide glycosides of marine origin 査読

Kiyotake Suenaga, Hiroshi Hoshino, Takanori Yoshii, Kazunori Mori, Hiroki Sone, Yuhki Bessho, Akira Sakakura, Ichiro Hayakawa, Kiyoyuki Yamada, Hideo Kigoshi

TETRAHEDRON 62 ( 33 ) 7687 - 7698 2006年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

The enantioselective synthesis of aurisides A and B, macrolide glycosides of marine origin, was achieved by a convergent approach. The C1-C9 segment 4 was prepared from (R)-pantolactone, and the C10-C17 segment 14 was synthesized from (R)-glycidyl trityl ether. The Nozaki-Hiyama-Kishi reaction between 4 and 14 and subsequent reactions gave seco acid 10, which was converted into the aglycon (3) of aurisides by construction of the 14-membered lactone and bromine-substituted conjugated diene. The glycosylation reaction of the aglycon provided aurisides A and B. (c) 2006 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2006.05.077

Synthesis and biological activity of mycalolide analogs 査読

Kiyotake Suenaga, Tomoyuki Kimura, Takeshi Kuroda, Keita Matsui, Saori Miya, Satomi Kuribayashi, Akira Sakakura, Hideo Kigoshi

TETRAHEDRON 62 ( 35 ) 8278 - 8290 2006年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

Mycalolide analog 4, consisting only of the side chain of mycalolide B (2), a trisoxazole macrolide of marine origin, was stereoselectively synthesized using Roush crotylboration, an Evans aldol reaction, and a Paterson aldol reaction as key steps. The analog 4 was found to have strong actin-depolymerizing activity. (c) 2006 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2006.06.046

P-81 ENANTIOSELECTIVE POLYENE HALOCYCLIZATION INDUCED BY NUCLEOPHILIC CHIRAL PHOSPHINES

Sakakura Akira, Ukai Atsushi, Ishihara Kazuaki

International Symposium on the Chemistry of Natural Products 2006 "P - 81" 2006年7月

Development of environmentally benign catalytic dehydration process 査読

Akira Sakakura, Kazuaki Ishihara

JOURNAL OF SYNTHETIC ORGANIC CHEMISTRY JAPAN 64 ( 6 ) 651 - 663 2006年6月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：SOC SYNTHETIC ORGANIC CHEM JPN

More environmentally benign alternatives to current chemical processes, especially large-scale fundamental reactions, are highly desirable for many reactions. We have developed bulky diary-lammonium pentafluorobenzenesulfonates la and 2a as mild and extremely active dehydration catalysts. In the presence of the catalysts, dehydrative cyclization of 1, 3, 5-triketones and ester condensation of carboxylic acids with equimolar amounts of alcohols are performed in heptane by heating at 80 V without the removal of water. We have also developed an efficient molybdenum oxide-catalyzed dehydrative cyclization of serine, threonine, and cysteine derivatives, which gives oxazolines and thiazolies. In the presence of molybdenum oxides, the reaction is carried out by heating at azeotropic reflux with the removal of water. Phosphate monoesters are synthesized from a mixture of phosphoric acid and alcohols in the presence of tributylamine. The reaction is promoted by nucleophilic bases such as N-butylimidazole. The hydroxyl groups of amino alcohols, such as 5'-hydroxyl group of 2, 3'-O-isopropylidene ribonucleosides, are phosphorylated selectively.

DOI： 10.5059/yukigoseikyokaishi.64.651

Chiral 1,1 '-binaphthyl-2,2 '-diammonium salt catalysts for the enantioselective Diels-Alder reaction with alpha-acyloxyacroleins 査読

Akira Sakakura, Kenji Suzuki, Kazuhiko Nakano, Kazuaki Ishihara

ORGANIC LETTERS 8 ( 11 ) 2229 - 2232 2006年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

A diammonium salt of chiral 1,1'-binaphthyl-2,2'-diamine and trifluoromethanesulfonimide (Tf2NH) shows excellent catalytic activity and enantioselectivity for the Diels-Alder reaction of alpha-acyloxyacroleins with cyclic dienes. For example, in the presence of 5 mol % of the ammonium catalyst, the Diels-Alder reaction of alpha-(cyclohexanecarbonyloxy) acrolein with cyclopentadiene proceeded in EtCN at -75 degrees C to give the adducts in 88% yield with 92% exo and 91% ee. This catalyst can be easily prepared in situ by mixing the commercially available chiral diamine and Tf2NH.

DOI： 10.1021/ol060490l

Study of the interaction between actin and antitumor substance aplyronine A with a novel fluorescent photoaffinity probe 査読

Takeshi Kuroda, Kiyotake Suenaga, Akira Sakakura, Tomohisa Handa, Kazuhito Okamoto, Hideo Kigoshi

Bioconjugate Chemistry 17 ( 2 ) 524 - 529 2006年3月

記述言語：英語掲載種別：研究論文（学術雑誌）

The interaction between actin and aplyronine A, a potent antitumor and actin-depolymerizing substance of marine origin, was investigated by photoaffinity labeling experiments. Photoaffinity probes consisting of a side-chain portion of aplyronine A as a ligand, a diazirine moiety as a photoaffinity group, and a fluorophore as a detecting group were synthesized. Photolabeling experiments between actin and the probe were carried out. Actin was successfully photolabeled by the fluorescent probe and visualized clearly. The present results provide the first chemical evidence for the direct interaction between actin and the side-chain portion of aplyronine A. © 2006 American Chemical Society.

DOI： 10.1021/bc050324i

Bulky diarylammonium arenesulfonates as mild and extremely active dehydrative ester condensation catalysts 査読

Akira Sakakura, Shoko Nakagawa, Kazuaki Ishihara

Tetrahedron 62 ( 2-3 ) 422 - 433 2006年1月

記述言語：英語掲載種別：研究論文（学術雑誌）

More environmentally benign alternatives to current chemical processes, especially large-scale, fundamental reactions like ester condensations, are highly desirable for many reactions. Bulky diarylammonium pentafluorobenzenesulfonates and tosylates serve as extremely active dehydration catalysts for the ester condensation reaction of carboxylic acids with equimolar amounts of sterically demanding alcohols and acid-sensitive alcohols. Typically, the esterification reaction is performed in heptane by heating at 80°C in the presence of 1 mol% of the catalyst without removing water. Esterification with primary alcohols proceeds without solvents even at room temperature. Furthermore, 4-(N-mesitylamino)polystyrene resin-bound pentafluorobenzenesulfonate can be recycled more than 10 times without a loss of activity. © 2005 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2005.09.059

P-12 酸化モリブデン触媒を用いる脱水環化反応によるオキサゾリン、チアゾリンの効率的合成(ポスター発表の部)

坂倉彰, 近藤玲, 梅村周平, 石原一彰

天然有機化合物討論会講演要旨集 ( 47 ) 475 - 480 2005年9月

記述言語：日本語出版者・発行元：天然有機化合物討論会

Oxazoline, oxazole, thiazoline, and thiazole rings are important constituents of numerous bioactive natural products and pharmaceuticals. The biosynthesis of many naturally occurring oxazolines and thiazolines appears to involve the dehydrative cyclization of serine, threonine, and cysteine residues. Oxazoles and thiazoles are synthesized by the oxidation of oxazolines and thiazolines, respectively. We describe here a biomimetic synthesis of oxazolines and thiazolines catalyzed by molybdenum (IV or VI) oxides, their mode of cyclization is retentive at the β-position. In the course of screening various metal oxides as catalysts for the dehydrative cyclization of dipeptides 1a and 1b, we found that molybdenum oxides had good catalytic activities. Interestingly, the ammonium salts of molybdenum(VI) oxides, (NH_4)_6Mo_7O_<24>・4H_2O and (NH_4)_2MoO_4, exhibited remarkable catalytic activities and gave oxazolines 2a and 2b in a short reaction time, along with small amounts of 3a and 3b. Next, we examined the dehydrative cyclization of cysteine derivatives 4a and 4b to thiazolines 5a and 5b using molybdenum oxides as catalysts. In the case of the dehydrative cyclization of 4a, (NH_4)_6Mo_7O_<24>・4H_2O, (NH_4)_2MoO_4 and MoO_2(acac)_2 showed excellent catalytic activities. MoO_2(acac)_2 could catalyze the dehydrative cyclization of 4b, to give 5b in 70% yield along with 5c (15%). To the best of our knowledge, this is the first example of the catalytic dehydrative cyclization of dipeptide substrates that include serine, threonine, and cysteine residues. A key synthetic intermediate 11 of hennoxazole A and bis(oxazoline)s 13a and 13b were synthesized by the dehydrative cyclization using molybdenum oxide catalysts. In addition, polyaniline-supported MoO_2(acac)_2 could easily be recovered and reused.

DOI： 10.24496/tennenyuki.47.0_475

Selective synthesis of phosphate monoesters by dehydrative condensation of phosphoric acid and alcohols promoted by nucleophilic bases 査読

Akira Sakakura, Mikimoto Katsukawa, Kazuaki Ishihara

Organic Letters 7 ( 10 ) 1999 - 2002 2005年5月

記述言語：英語掲載種別：研究論文（学術雑誌）

(Chemical Equation Presented) Phosphate monoesters are synthesized from a mixture of phosphoric acid (1 or 2 equiv) and alcohols (1 equiv) in the presence of tributylamine. The reaction is promoted by nucleophilic bases such as N-alkylimidazole and 4-(N,N-dialkylamino)pyridine. 2′,3′-I- Isopropylidene ribonucleosides are selectively converted to their 5′-monophosphates without the protection of amino groups in nucleobases. © 2005 American Chemical Society.

DOI： 10.1021/ol0504796

Molybdenum oxides as highly effective dehydrative cyclization catalysts for the synthesis of oxazolines and thiazolines 査読

Akira Sakakura, Rei Kondo, Kazuaki Ishihara

Organic Letters 7 ( 10 ) 1971 - 1974 2005年5月

記述言語：英語掲載種別：研究論文（学術雑誌）

(Chemical Equation Presented) In the presence of molybdenum oxide the dehydrative cyclization of N-acylserines, N-acylthreonines, and N-acylcysteines can be carried out under Dean-Stark conditions in toluene to give oxazolines and thiazolines. The ammonium salts (NH4)6Mo 7O24·4H2O and (NH4) 2MoO4 have excellent catalytic activities for the dehydrative cyclization of serine and threonine derivatives, and the acetylacetonate complex MoO2(acac)2 has a remarkable catalytic activity for the dehydrative cyclization of cysteine derivatives. In addition, polyaniline-supported MoO2(acac)2 can easily be recovered and reused. © 2005 American Chemical Society.

DOI： 10.1021/ol050543j

Bulky diarylammonium arenesulfonates as selective esterification catalysts 査読

Kazuaki Ishihara, Shoko Nakagawa, Akira Sakakura

Journal of the American Chemical Society 127 ( 12 ) 4168 - 4169 2005年3月

記述言語：英語掲載種別：研究論文（学術雑誌）

More environmentally benign alternatives to current chemical processes, especially large-scale, fundamental reactions such as ester condensations, are highly desirable for many reactions. Bulky diarylammonium pentafluorobenzenesulfonates and tosylates serve as extremely active dehydration catalysts for the ester condensation reaction of carboxylic acids with equimolar amounts of sterically demanding alcohols and acid-sensitive alcohols. Typically, the esterification reaction is performed in heptane by heating at 80 °C in the presence of 1 mol % of the catalyst without removing water. Esterification with primary alcohols proceeds without solvents even at room temperature. Furthermore, 4-(N-mesitylamino)polystyrene resin-bound pentafluorobenzenesulfonate can be recycled more than 10 times without activity loss. Copyright © 2005 American Chemical Society.

DOI： 10.1021/ja050223v

Formal synthesis of optically active ingenol via ring-closing olefin metathesis 査読

Kazushi Watanabe, Yuto Suzuki, Kenta Aoki, Akira Sakakura, Kiyotake Suenaga, Hideo Kigoshi

Journal of Organic Chemistry 69 ( 23 ) 7802 - 7808 2004年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

The construction of strained carbon skeletons by ring-closing olefin metathesis (RCM) was investigated. With well-designed diene 4, RCM was found to be applicable to the formation of a highly strained inside-outside bicyclo[4.4.1]undecane skeleton of ingenol, a bioactive diterpenoid, and formal total synthesis of optically active ingenol (1) was achieved. The key features of this synthesis are construction of an A-ring by spirocyclization of the ketone with an allylic chloride unit, 26, and ring closure of a B-ring by olefin metathesis. Starting from Funk's keto ester 6, the key intermediate aldehyde 9 in Winkler's total synthesis was synthesized in eight steps in 12.5% overall yield. This strategy of direct cyclization of a strained inside-outside skeleton provided the first easy access to optically active ingenol.

DOI： 10.1021/jo048833l

Spongiacysteine, a novel cysteine derivative from marine sponge Spongia sp. 査読

Keiko Kobayashi, Hiroki Shimogawa, Akira Sakakura, Toshiaki Teruya, Kiyotake Suenaga, Hideo Kigoshi

Chemistry Letters 33 ( 10 ) 1262 - 1263 2004年10月

記述言語：英語掲載種別：研究論文（学術雑誌）

A novel cysteine derivative, spongiacysteine (1), was isolated from marine sponge Spongia sp. The gross structure was elucidated by detailed spectroscopic analysis, and the absolute stereostructure was established by its total synthesis. This compound showed moderate antimicrobial activity against rice blast fungus Pyricularia oryzae.

DOI： 10.1246/cl.2004.1262

99(P-32) 光学活性インゲノールの合成(ポスター発表の部)

渡邉和志, 鈴木佑人, 青木健太, 坂倉彰, 末永聖武, 木越英夫

天然有機化合物討論会講演要旨集 ( 46 ) 569 - 574 2004年10月

記述言語：日本語出版者・発行元：天然有機化合物討論会

Ingenol is a diterpenoid isolated from Euphorbia ingens, possessing a bicyclo[4.4.1]undecane skeleton with a highly strained inside, outside-intrabridgehead stereochemistry. Several strategies for construction of the unique skeleton have been reported, however, direct cyclization to the inside, ousidet-bicyclo[4.4.1]undecane system has not been reported. Recently, two total syntheses in a racemic form using the aforementioned strategies were reported by Winkler and Tanino-Kuwajima. We would like to report the construction of strained carbon skeletons of ingenol by direct cyclization with ring-closing olefin metathesis (RCM). With well-designed diene compounds 4, 23, and 24, RCM was found to be applicable to the formation of a highly strained skeleton of ingenol, and formal total synthesis of optically active ingenol (1) was achieved. The key features of this synthesis are construction of an A-ring by spirocyclization of ketone 21 with an allylic chloride unit and ring closure of a B-ring by olefin metathesis. Starting from Funk's keto ester 17, the key intermediate aldehyde 27 in Winkler's total synthesis was synthesized in eight steps in 12.5% overall yield. This strategy of direct cyclization of a strained inside-outside skeleton provided the first easy access to optically active ingenol.

DOI： 10.24496/tennenyuki.46.0_569

58(P-35) 海洋産抗腫瘍性物質アプリロニンA関連化合物の合成と生物活性(ポスター発表の部)

末永聖武, 黒田武史, 半田知久, 宮沙織, 兼松憲吾, 坂倉彰, 山田靜之, 木越英夫, 平田邦生, 高田昌樹, 加藤健一, 村岡真, 山本雅貴, 田中宏志

天然有機化合物討論会講演要旨集 ( 46 ) 323 - 328 2004年10月

記述言語：日本語出版者・発行元：天然有機化合物討論会

Aplyronine A (1) is a potent antitumor macrolide isolated from the sea hare Aplysia kurodai, and mycalolide B (2) is a cytotoxic and antifungal macrolide isolated from a sponge of the genus Mycale. These macrolides interact with actin, one of the major proteins in cytoskeleton. We achieved total synthesis of aplyronine A (1) and its analogs and investigated the structure-activity relationships. We improved the synthesis of the side chain portion of aplyronine A (1) by using the Paterson aldol reaction and subsequent stereoselective reduction with Me_4NBH(OAc)_3 as key steps. The synthetic analogs 3 and 4 that only consists of the side chain part of aplyronine A (1) and mycalolide B (2) turned out to exhibit a strong actin depolymerizing activity, considering the size of the molecule. This result revealed that the side chain portion in aplyronine A (1) and mycalolide B (2) was responsible for the potent activity of 1 and 2. Analysis of the interaction of aplyronine analogs, such as 30 and 31, with actin by a photoaffinity labeling method has been carried out. Crystallization and X-ray structure analysis of actin complex with aplyronine A (1) also are in progress.

DOI： 10.24496/tennenyuki.46.0_323

Jolkinolide D pharmacophore: Synthesis and reaction with biomolecules 査読

Akira Sakakura, Yui Takayanagi, Hiroki Shimogawa, Hideo Kigoshi

Tetrahedron 60 ( 33 ) 7067 - 7075 2004年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

To obtain information on the chemical modification of biomolecules with jolkinolide D, a bioactive diterpenoid of plant origin, jolkinolide D pharmacophore was synthesized, and its reactivity toward amino acids, nucleosides, and DNA was investigated. © 2004 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2003.08.080

Synthesis and actin-depolymerizing activity of mycalolide analogs 査読

Kiyotake Suenaga, Saori Miya, Takeshi Kuroda, Tomohisa Handa, Kengo Kanematsu, Akira Sakakura, Hideo Kigoshi

Tetrahedron Letters 45 ( 28 ) 5383 - 5386 2004年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

Mycalolide analog 4, consisting only of the side chain of mycalolide B (2), was stereoselectively synthesized and was found to have strong actin-depolymerizing activity. © 2004 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2004.05.078

Nonspecificity Induces Chiral Specificity in the Folding Transition of Giant DNA 査読

Michiko Ito, Akira Sakakura, Naomi Miyazawa, Shizuaki Murata, Kenichi Yoshikawa

Journal of the American Chemical Society 125 ( 42 ) 12714 - 12715 2003年10月

記述言語：英語掲載種別：研究論文（学術雑誌）

The all-or-none type DNA folding transition from a coil to globule can be differentiated by the chirality of the triamines. The fluorescent microscope observation on single DNA molecules makes it clear that the tripeptides obtained from naturally occurring basic amino acids (L-lysine or L-arginine) can compact DNA molecules at concentrations lower than those from D-isomers. Nanometer-sized beads are found in the AFM images on the folded DNA molecule. Copyright © 2003 American Chemical Society.

DOI： 10.1021/ja036745x

106(P-60) ジョルキノライドDファーマコホア : 合成とアミノ酸、ヌクレオシドおよびDNAに対する反応性(ポスター発表の部)

坂倉彰, 高柳維, 下川浩輝, 木越英夫

天然有機化合物討論会講演要旨集 ( 44 ) 623 - 628 2002年9月

記述言語：日本語出版者・発行元：天然有機化合物討論会

Jolkinolide D (1) is a diterpenoid isolated from Euphorbia jolkini Boiss in 1974, and its stereostructure was recently determined by X-ray crystallographic analysis. It inhibited tumor invasion into the basement membrane and induced apoptosis in tumor cells. Jolkinolide D (1) has a γ,δ-unsaturated-β-hydroxy-α-methylene lactone unit as the pharmacophore structure, which suggests that jolkinolide D (1) might alkylate biomolecules such as proteins and DNA irreversibly. Since there are no other compounds that have the pharmacophore, reactivities of the unit toward nucleophiles have not hitherto been investigated. For the purpose of obtaining preliminary information on the chemical modification of biomolecules with jolkinolide D (1), jolkinolide D pharmacophore (2) was synthesized from 6-(tert-butyldimethylsilyloxy)-3-methyl-2-cyclohexenone (3) and 2-iodoallylalcohol (4), and its reactivity toward amino acids, nucleosides, and DNA was investigated. It was found that the order of reactivity of jolkinolide D pharmacophore (2) toward the nucleophiles in the amino acids at pH 7.5 is the thiol group in L-cysteine and glutathione > the imidazolyl group in L-histidine, the α-amino groups in amino acids > the carboxyl groups in amino acids. Jolkinolide D pharmacophore (2) alkylated 2'-deoxyguanosine at the N-1 position (pH 7.5) and thymidine at the N-3 position (pH 8.7), and modified DNA at the same sites in lower yields.

DOI： 10.24496/tennenyuki.44.0_623

Jolkinolide D pharmacophore: Synthesis and reaction with amino acids, nucleosides, and DNA 査読

Akira Sakakura, Yui Takayanagi, Hideo Kigoshi

Tetrahedron Letters 43 ( 34 ) 6055 - 6058 2002年8月

記述言語：英語掲載種別：研究論文（学術雑誌）

For the purpose of obtaining preliminary information on the chemical modification of biomolecules with jolkinolide D, a bioactive diterpenoid of plant origin, jolkinolide D pharmacophore, was synthesized and its reactivity toward amino acids, nucleosides, and DNA was investigated. © 2002 Published by Elsevier Science Ltd.

DOI： 10.1016/S0040-4039(02)01195-4

Effect of molecular sieves in the liquid-phase synthesis of nucleotides via the phosphoramidite method 査読

Yoshihiro Hayakawa, Akiyoshi Hirata, Jun-Ichiro Sugimoto, Rie Kawai, Akira Sakakura, Masanori Kataoka

Tetrahedron 57 ( 42 ) 8823 - 8826 2001年10月

記述言語：英語掲載種別：研究論文（学術雑誌）

It is demonstrated that the reaction of a nucleoside phosphoramidite and a nucleoside aided by a suitable promoter in the presence of molecular sieves 3A or 4A in a liquid phase is efficiently performed by the use of stoichiometric amounts of the reactants to give the desired coupling product in an excellent yield. © 2001 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0040-4020(01)00880-8

A facile synthesis of 5′-end solid-anchored, 3′-end free oligodeoxyribonucleotides via the (5′→3′)-elongated phosphoramidite strategy 査読

Akira Sakakura, Yoshihiro Hayakawa

Nucleosides, Nucleotides and Nucleic Acids 20 ( 3 ) 213 - 227 2001年

記述言語：英語掲載種別：研究論文（学術雑誌）

It is demonstrated that not only N2- but also O 6-protection of the guanine base is necessary for obtaining the oligodeoxyribonucleotides in high yields and at a high purity in the solid-phase synthesis via the (5′ → 3′)-chain elongated phosphoramidite approach.

DOI： 10.1081/NCN-100002082

Acid/azole complexes as highly effective promoters in the synthesis of DNA and RNA oligomers via the phosphoramidite method 査読

Y. Hayakawa, R. Kawai, A. Hirata, J. I. Sugimoto, M. Kataoka, A. Sakakura, M. Hirose, R. Noyori

Journal of the American Chemical Society 123 ( 34 ) 8165 - 8176 2001年

記述言語：英語掲載種別：研究論文（学術雑誌）

The utility of various kinds of acid salts of azole derivatives as promoters for the condensation of a nucleoside phosphoramidite and a nucleoside is investigated. Among the salts, N-(phenyl)imidazolium triflate, N-(p-acetylphenyl)imidazolium triflate, N-(methyl)benzimidazolium triflate, benzimidazolium triflate, and N-(phenyl)imidazolium perchlorate have shown extremely high reactivity in a liquid phase. These reagents serve as powerful activators of deoxyribonucleoside 3′-(allyl N,N-diisopropylphosphoramidite)s or 3′-(2-cyanoethyl N,N-diisopropylphosphoramidite)s employed in the preparation of deoxyribonucleotides, and 3′-O-(tert-butyldimethylsilyl)ribonucleoside 2′-(N,N-diisopropylphosphoramidite)s or 2′-O-(tert-butyldimethylsilyl)-ribonucleoside 3′-(N,N-diisopropylphosphoramidite)s used for the formation of 2′-5′ and 3′-5′ internucleotide linkages between ribonucleosides, respectively. The azolium salt has allowed smooth and high-yield condensation of the nucleoside phosphoramidite and a 5′-O-free nucleoside, in which equimolar amounts of the reactants and the promoter are employed in the presence of powdery molecular sieves 3A in acetonitrile. It has been shown that some azolium salts serve as excellent promoters in the solid-phase synthesis of oligodeoxyribonucleotides and oligoribonucleotides. For example, benzimidazolium triflate and N-(phenyl)imidazolium triflate can be used as effective promoters in the synthesis of an oligodeoxyribonucleotide, 5′CGACACCCAATTCTGAAAAT3′ (20mer), via a method using O-allyl/N-allyloxycarbonyl-protected deoxyribonucleoside 3′-phosphoramidites or O-(2-cyanoethyl)/N-phenoxyacetyl-protected deoxyribonucleotide 3′-phosphoramidite as building blocks, respectively, on high-cross-linked polystyrene resins. Further, N-(phenyl)imidazolium triflate is useful for the solid-phase synthesis of oligoribonucleotides, such as 5′AGCUACGUGACUACUACUUU3′ (20mer), according to an allyl/allyloxycarbonyl-protected strategy. The utility of the azolium promoter has been also demonstrated in the liquid-phase synthesis of some biologically important substances, such as cytidine-5′-monophosphono-N-acetylneuraminic acid (CMP-Neu5Ac) and adenylyl(2′-5′)adenylyl(2′-5′)adenosine (2-5A core).

DOI： 10.1021/ja010078v

A novel synthesis of oligonucleotide-peptide conjugates with a base- labile phosphate linker between the two components according to the allyl- protected phosphoramidite strategy 査読

Akira Sakakura, Yoshihiro Hayakawa

Tetrahedron 56 ( 26 ) 4427 - 4435 2000年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Elsevier Ltd

An efficient synthesis of base-labile nucleotide-peptide conjugates has been accomplished, in which the two components are directly linked between the terminal hydroxyl of a nucleotide and the hydroxyl of a serine or threonine residue of a peptide by a phosphodiester bond. This synthesis utilizes the phosphoramidite method with allyl for the phosphate linkages and the C-terminal of the peptide and allyloxycarbonyl for the nucleoside bases and the N-terminal of the peptide. In this synthesis, the removal of the allylic protecting groups and the detachment of the products was achieved under non-basic or mild basic conditions to bring about no conspicuous decomposition of the labile phosphate linker, and thus the target conjugates were obtained at a high purity and in high yields. (C) 2000 Elsevier Science Ltd.

DOI： 10.1016/S0040-4020(00)00376-8

An efficient synthesis of nucleotides via the phosphoramidite method using a triflic acid salt of an imidazole-related compound as a promoter.

A. Sakakura, M. Kataoka, R. Kawai, Y. Hayakawa

Nucleic acids symposium series ( 44 ) 137 - 138 2000年

記述言語：英語掲載種別：研究論文（学術雑誌）

N-Phenylimidazolium triflate and N-methylbenzimidazolium triflate, new imidazole-related compound/triflic acid-complex type of promoters in the phosphoramidite method, has been developed. These reagents are, particularly, useful for internucleotide-bond formation with lowly reactive reactants and have allowed an efficient, high-yield synthesis of oligodeoxyribonucleotides both in a solution phase and on a solid supports.

DOI： 10.1093/nass/44.1.137

A novel approach to oligodeoxyribonucleotides bearing phosphoric acid esters at the 3'-terminals via the phosphoramidite method with allyl protection: An efficient synthesis of base-labile nucleotide-amino acid and - peptide conjugates 査読

Akira Sakakura, Yoshihiro Hayakawa, Hitoshi Harada, Masaaki Hirose, Ryoji Noyori

Tetrahedron Letters 40 ( 23 ) 4359 - 4362 1999年6月

記述言語：英語掲載種別：研究論文（学術雑誌）

A new method for synthesis of 3'-end-phosphorylated DNA oligomers via the phosphoramidite method with allyl protection has been developed. This method is particularly useful for the preparation of derivatives with base- labile structures such as oligoDNA-OPO(OH)OCH2CH(R)Z, in which Z is an electron-withdrawing function. For example, a oligonucleotide-amino acid conjugate, 5'TGTCGACACCCAATT3'-OPO(OH)OCH2CH(NH2)COOH, and a oligonucleotide-peptide conjugate, 5'TGTCGACACCCAATT3'- OPO(OH)OCH2CH(NH2)CONHCH2COOH, have been obtained in high purity.

DOI： 10.1016/S0040-4039(99)00748-0

Aplyronine A, a potent antitumor substance of marine origin, aplyronines B and C, and artificial analogues: Total synthesis and structure-cytotoxicity relationships 査読

Hideo Kigoshi, Kiyotake Suenaga, Tsuyoshi Mutou, Takeshi Ishigaki, Toshiyuki Atsumi, Hiroyuki Ishiwata, Akira Sakakura, Takeshi Ogawa, Makoto Ojika, Kiyoyuki Yamada

Journal of Organic Chemistry 61 ( 16 ) 5326 - 5351 1996年8月

記述言語：英語掲載種別：研究論文（学術雑誌）

The enantioselective total synthesis of aplyronine A (1), a potent antitumor substance of marine origin, was achieved by a convergent approach. Three segments 4, 5, and 6, corresponding to the C5-C11, C21-C27, and C28-C34 portions of aplyronine A (1), were prepared using the Evans aldol reaction and the Sharpless epoxidation as key steps. The coupling reaction of 4 with iodide 7 followed by Julia olefination with sulfone 8 gave the C5-C20 segment 9, while the Julia coupling reaction between segments 5 and 6 provided the C21-C34 segment 10. Julia olefination between segments 9 and 10 and the subsequent four-carbon homologation reaction led to seco acid 83, which was converted into aplyronine A (1) by Yamaguchi lactonization followed by the introduction of two amino acids. The use of the [(3,4-dimethoxybenzyl)oxy]methyl group as a protecting group for the hydroxyl at C29 was crucial for this synthesis. The enantioselective synthesis of two natural congeners, aplyronines B (2) and C (3), was also carried out using the intermediates for the synthesis of 1, which determined the absolute stereostructures of 2 and 3 unambiguously. To study the structure-cytotoxicity relationships of aplyronines, artificial analogues of 1 were synthesized and their cytotoxicities were evaluated: the trimethylserine moiety, two hydroxyl groups, and the side chain portion in 1 turned out to be important in the potent cytotoxicity shown by 1. Biological studies with aplyronine A (1) showed that 1 inhibited polymerization of G-actin to F-actin and depolymerized F-actin to G-actin.

DOI： 10.1021/jo9606113

Absolute stereochemistry and synthesis of aplyronines B and C, the congeners of aplyronine A, a potent antitumor substance of marine origin 査読

Kiyotake Suenaga, Takeshi Ishigaki, Akira Sakakura, Hideo Kigoshi, Kiyoyuki Yamada

Tetrahedron Letters 36 ( 28 ) 5053 - 5056 1995年7月

Total synthesis of aplyronine A, a potent antitumor substance of marine origin 査読

Kigoshi Hideo, Ojika Makoto, Ishigaki Takeshi, Suenaga Kiyotake, Mutou Tsuyoshi, Sakakura Akira, Ogawa Takeshi, Yamada Kiyoyuki

Journal of the American Chemical Society 116 ( 16 ) 7443 - 7444 1994年8月

Synthetic Studies on Aplyronine A, a Potent Antitumor Substance of Marine Origin: Stereocontrolled Synthesis of the C21-C34 Segment 査読

Hideo Kigoshi, Makoto Ojika, Kiyotake Suenaga, Tsuyoshi Mutou, Junko Hirano, Akira Sakakura, Takeshi Ogawa, Masanori Nisiwaki, Kiyoyuki Yamada

Tetrahedron Letters 35 ( 8 ) 1247 - 1250 1994年2月

23 海産抗腫瘍性マクロリド、アプリロニンAの立体化学と合成研究(口頭発表の部)

木越英夫, 小鹿一, 石垣剛, 末永聖武, 武藤毅, 坂倉彰, 小川武, 西脇正憲, 塚田格, 山田靜之

天然有機化合物討論会講演要旨集 ( 35 ) 174 - 178 1993年9月

記述言語：日本語出版者・発行元：天然有機化合物討論会

Aplyronine A (1) is a potent antitumor macrolide isolated as a minute component from the sea hare Aplysia kurodai. The gross structure of 1 was determined by the spectral analysis and chemical degradation. We report herein the absolute stereostructure of 1 and the result of the synthetic study. Chemical degradation of 1 afforded five fragments 2-6. Enantioselective syntheses of the fragments 4a and 5a were performed to disclose the absolute stereochemistry of seven chiral centers (C7-C10, C13, C17, and C19). HPLC analyses of the fragments 2 and 3 using chiral columns disclosed that N,N,O-trimethylserine and N,N-dimethylalanine moieties of 1 were scalemic mixtures (S:R=52:48 for 2; 72:28 for 3). On the basis of the result of the previous and present studies, the absolute stereostructure of aplyronine A (1) was elucidated unambiguously. The synthetic study of 1 was carried out using the Evans aldol reaction and the Sharpless epoxidation reaction as key steps. Starting from N-propionylurethane 11, the C5-C20 segment 13 and the C21-C34 segment 16 were synthesized. The Julia coupling reaction of 13 with 16 followed by four-carbons homologation and lactonization provided 24-membered lactone 17.

DOI： 10.24496/tennenyuki.35.0_174

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