Hiroko Matsukura

An efficient strategy for the iterative synthesis of a trans-fused polytetrahydropyran ring system via SmI2-induced reductive intramolecular cyclization

A highly efficient strategy for the iterative synthesis of a trans-fused polytetrahydropyran ring system was developed. The new iterative method involves SmI2-induced reductive intramolecular cyclization of an aldehyde and a β-alkoxy acrylate as the key step, producing a 2,3-trans-tetrahydropyran ring.

Efficient strategy for the iterative synthesis of trans-fused polycyclic ether via SmI2-induced reductive intramolecular cyclization

Abstract A highly efficient strategy for the iterative synthesis of a trans-fused polycyclic ether ring system has been developed. The new iterative method involves SmI2-induced reductive intramolecular cyclization of an aldehyde and a β-alkoxy acrylate as the key step, producing a 2,3-trans-tetrahydropyran or oxepane ring. The syntheses of trans-fused 6,6,6-tricyclic, 6,7,6-tricyclic, and 6,7,7,6-tetracyclic ethers were effectively achieved based on the newly developed method.

Determination of absolute structure of (−)-oudemansin b

(−)-Oudemansin B (1 synthesized from (2R,3S)-2,3-epoxybutyrate 2 based on microbial asymmetric reduction of ketone was proved to be identical with natural oudemansin B (1), which established that the absolute configuration of 1 is 9S, 10S.

Stereoselective synthesis of six- and seven-membered ether rings based on the ring expansion

Abstract Six- and seven-membered ether rings were stereoselectively synthesized based on the rearrangement of the cyclic ether with the simultaneous ring expansion. Treatment of ether having a mesylate or bromide group as the leaving group on the side chain with Zn(OAc)2 or AgOAc stereoselectively produced the ring expanded ether in good yield.

Stereoselective synthesis of tetrahydropyran and oxepane systems by the endo-cyclization of hydroxy styrylepoxides

Tetrahydropyran and oxepane systems were stereoselectively synthesized based on the endo-cyclization of epoxy alcohol having a styryl group next to the epoxide.

Synthetic studies on brevetoxin-B. Part 3: Stereoselective synthesis of the IJK-ring system

Abstract The EFG-ring system of brevetoxin-B, having an α-methyl group on the D-ring, was stereoselectively synthesized based on the stereoselective Michael addition of the α-methyl group, novel ring-expansion reaction, and 6-endo-cyclizations of the vinylepoxide and methylepoxide.

Stereoselective synthesis of the C- and CD-ring systems of hemibrevetoxin B

Abstract The 7, 7-membered CD ring system of hemibrevetoxin B was stereoselectively synthesized. The crucial steps involve the Sharpless asymmetric epoxidation, cyclization to the 6-membered ether, and double rearrangement of the 6, 6-membered bicyclic ether with the simultaneous ring expansion.

SYNTHESIS OF THE RIGHT HALF OF MYCALAMIDE A. A FORMAL TOTAL SYNTHESIS

Abstract The right half 5 of Mycalamide A (1) was synthesized via α,β-unsaturated ketone 11 which was prepared starting from (S)-malic acid or (R)- and (S)-pantolactones, stereoselectively.

Further study on SmI2-induced reductive intramolecular cyclization: synthesis of polycyclic ethers having an angular methyl group

The SmI2-induced reductive intramolecular cyclization of an aldehyde and β-alkoxy acrylate was further investigated for the synthesis of polycyclic ethers having an angular methyl group. The cyclization produced 6,6- and 6,7-membered bicyclic ethers having a methyl group at C2 or C6 and C2 or C7 position, respectively.

Lipase catalyzed enantioselective hydrolysis of 2-methyl 3-acetoxy esters

Abstract Highly enantioselective hydrolyses of syn -3-acetoxy-2-methyl ester and anti -3-acetoxy-2-methyl esters with lipase “Amano A” and lipase “Amano A-6” isolated from Aspergillus niger , are described.