Goh Matsuo

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.

Stereoselective syntheses of trans-fused 6,6- and 6,7-membered ether ring systems having an angular methyl group based on SmI2-induced reductive intramolecular cyclization

Abstract Highly stereoselective syntheses of trans -fused 6,6- and 6,7-membered ether ring systems having an angular methyl group were achieved based on SmI 2 -induced reductive intramolecular cyclizations of an aldehyde or a methyl ketone and a β-alkoxy acrylate.

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.

Efficient convergent synthesis of a trans-fused 6-6-6-6-membered tetracyclic ether ring system

Abstract A very efficient convergent strategy for the construction of the trans -fused 6-6-6-6-membered tetracyclic ether ring system was developed based on the acetylide-triflate coupling of two tetrahydropyrans, oxidation of the alkyne group to an α-diketone, double cyclization to 6,6,6,6-membered tetracyclic diacetal, and stereoselective reduction of the diacetal with Et 3 SiH–TMSOTf.

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.

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.

Allyl C-glycosidations of totally unprotected glycals and allyltrimethylsilane with trimethylsilyl trifluoromethanesulfonate (TMSOTf)

Abstract Allyl C -glycosidations of the totally unprotected glycals, L-rhamnal ( 1 ), D-glucal ( 2 ), D-galactal ( 3 ) and D-fucal ( 4 ), with allyltrimethylsilane ( 5 ) using TMSOTf proceeded much more effectively than those of the corresponding acetylated glycals 10∼13 to furnish the unprotected and 2,3-unsaturated allyl α- C -glycosides 6∼9 in high yields, respectively.

Efficient C-arylglycosylation of 1-O-methyl sugar by novel use of TMSOTf-AgClO4 catalyst system

Abstract Highly β-stereoselective C-arylglycosylations of the 1-O-methyl sugars 1∼4 with 2-naphthol ( 9 ) were effectively achieved by novel combinational use of a catalytic amount of TMSOTf-AgClO 4 as an activator. Also, C-arylglycosylations of the 1-O-acetyl sugars 5∼8 with 9 in this way worked as well.

ENVIRONMENTALLY BENIGN ARYL C-GLYCOSIDATIONS OF UNPROTECTED SUGARS USING MONTMORILLONITE K-10 AS A SOLID ACID

Abstract Highly practical aryl C-glycosidations of unprotected 1-OMe and 1-OH sugars with phenol and naphthol derivatives were effectively realized using montmorillonite K-10 as an environmentally compatible solid acid in CHCl 3 or H 2 O.

Total synthesis of urdamycinone B via C-glycosidation of an unprotected sugar and Diels–Alder reaction of C-glycosyl juglone

The total synthesis of C-glycosyl angucycline, urdamycinone B 1, was achieved via C-glycosidation of naphthol 6 and the unprotected D-olivose 7, and Diels–Alder reaction of the unprotected C-glycosyl juglone 9 and the diene 17 as the key steps.