研究者詳細 - 髙村　浩由

Convergent total syntheses of gambierol and 16-epi-gambierol and their biological activities

Kadota, I, H Takamura, K Sato, A Ohno, K Matsuda, M Satake, Y Yamamoto

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 125 ( 39 ) 11893 - 11899 2003年10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 convergent total syntheses of gambierol (1) and 16-epi-gambierol (2) have been achieved. The ABC and FGH ring segments 4 and 5 were prepared from known compounds 6 and 13, respectively, by linear manners. The fragments prepared were connected by our own synthetic strategy including the intramolecular allylation of alpha-acetoxy ether followed by ring-closing metathesis to furnish the octacyclic ether 3. The diiodoalkene 45, prepared from 3, was converted to the Z-iodoalkene 50 via a novel and stereoselective hydrogenolysis followed by deprotection. Construction of the triene side chain was performed by the modified Stille coupling of 50 with the Z-vinylic stannane 41 to afford 1. The similar transformations were carried out on the epimeric octacycle 34 to give 2, which showed no toxicity against mice at the concentration of 14 mg/kg.

DOI： 10.1021/ja036984k

Total synthesis of gambierol

Kadota, I, H Takamura, K Sato, A Ohno, K Matsuda, Y Yamamoto

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 125 ( 1 ) 46 - 47 2003年1月

Concise synthesis of cyclic ethers via the palladium-catalyzed coupling of ketene acetal triflates and organozinc reagents. Application to the iterative synthesis of polycyclic ethers

Kadota, I, H Takamura, K Sato, Y Yamamoto

JOURNAL OF ORGANIC CHEMISTRY 67 ( 10 ) 3494 - 3498 2002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

The reaction of the ketene acetal triflates 9a-e and a zinc homoenolate 10 in the presence of a catalytic amount of Pd(PPh3)(4) gave the enol ethers 11a-e in good yields. The products were converted to the corresponding cyclic ethers 14a and 14b by hydroboration and lactonization. The present methodology allowed us to synthesize the DE and GH ring segment of gambierol in a concise manner. Iterative syntheses of the polycyclic ethers 26 and 32 are also described.

DOI： 10.1021/jo025566f

Syntheses of the AB and EFGH ring segments of gambierol

Kadota, I, C Kadowaki, CH Park, H Takamura, K Sato, PWH Chan, S Thorand, Y Yamamoto

TETRAHEDRON 58 ( 10 ) 1799 - 1816 2002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：PERGAMON-ELSEVIER SCIENCE LTD

Stereocontrolled syntheses of the AB and EFGH ring systems of gambierol (1) are described. The two key intermediates 3 and 55, representing the AB and EFGH ring frameworks, were prepared from 2-deoxy-D-ribose via linear sequences. Brown's asymmetric allylboration and the intramolecular hetero-Michael reaction were successfully applied to the construction of the A ring moiety. Synthesis of the EFGH ring segment 55 was achieved by the SmI2 mediated reductive cyclization, constructing the EF ring bearing two 1,3-diaxial methyl groups, and the palladium catalyzed coupling of enol triflate and zinc bishomoenolate, making the GH ring moiety. Attempted convergent approaches toward the EFGH ring framework- are also described. (C) 2002 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0040-4020(02)00039-X

Synthetic studies towards gambierol. Part 2: Synthesis of the EFGH ring segment

Kadota, I, C Kadowaki, H Takamura, Y Yamamoto

TETRAHEDRON LETTERS 42 ( 35 ) 6199 - 6202 2001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 EFGH ring segment of gambierol was synthesized from 2-deoxy-D-ribose in 40 steps. The present synthesis includes a SmI2-mediated reductive cyclization and a Pd-catalyzed coupling of enot triflate with a zinc bis-homoenolate as key steps. (C) 2001 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0040-4039(01)01205-9

Concise synthesis of cyclic ethers via the palladium-catalyzed coupling of ketene acetal triflates and a zinc homoenolate. Synthesis of the DE and GH ring segments of gambierol

Kadota, I, H Takamura, K Sato, Y Yamamoto

TETRAHEDRON LETTERS 42 ( 28 ) 4729 - 4731 2001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

Concise syntheses: of the DE and GH ring segments of gambierol (1) were achieved by the palladium-catalyzed coupling of ketene acetal triflates and a zinc homoenolate, followed by the hydroboration of the resulting cyclic enol ethers and subsequent lactonization. (C) 2001 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0040-4039(01)00824-3

Synthesis of the J ring segment of gambieric acid

Kadota, I, H Takamura, Y Yamamoto

TETRAHEDRON LETTERS 42 ( 21 ) 3649 - 3651 2001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：PERGAMON-ELSEVIER SCIENCE LTD

The J ring segment 2 of gambieric acid was synthesized stereoselectively by the coupling between the cyclic ether component 3 and the alkenyl iodide 4. The tetrahydropyran 3 was stereoselectively synthesized by the 6-endo-cyclization of a hydroxyepoxide prepared from deoxy-D-ribose. The side chain moiety 4 was prepared by the stereoselective hydrostannation of an internal alkyne. (C) 2001 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0040-4039(01)00530-5