研究者詳細 - 坂倉　彰

論文 - 坂倉　彰

分割表示 103 件中 41 - 60 件目／全件表示 >>

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

Web of Science

researchmap

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

Web of Science

researchmap

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

Web of Science

researchmap

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

Web of Science

researchmap

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.

Web of Science

researchmap

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

Web of Science

researchmap

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

Web of Science

researchmap

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

Web of Science

researchmap

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

Web of Science

researchmap

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

Web of Science

researchmap

　前のページ - 次のページ　

<坂倉 彰>

論文 - 坂倉 彰

<坂倉　彰>

論文 - 坂倉　彰