Yoshio Kita

Silica gel-catalyzed β-O-glucosylation of alcohols with 1,2-anhydro-3,4,6-tri-O-pivaloyl-α-d-glucopyranose

1,2-anhydro-3,4,6-tri-O-pivaloyl-α-d-glucopyranose (1a) was allowed to react with alcohols in the presence of solid acids such as silica gel and zeolite HY, to afford β-O-glucosides stereoselectively. Several natural glucosides were synthesized by the application of the present reaction.

Highly selective and facile synthesis of dihydro- and tetrahydropyridine dicarboxylic acid derivatives using electroreduction as a key step

Abstract Electroreduction of pyridinedicarboxylic acid derivatives 1a – g in methanol containing ammonium chloride using a divided cell brought about highly selective hydrogenation to give the corresponding dihydropyridines in good yields. From the electrolysis of dimethyl 2,3- and 2,5-pyridinedicarboxylates 1a , c , only the corresponding 1,2-dihydropyridine derivatives 2a , c were obtained in a regioselective manner while that of 2,4-, 2,6-, and 3,4- disubstituted pyridines 1b , d , e afforded the corresponding 1,4-dihydropyridines 2b , d , e selectively in good yields. Further hydrogenation of the resultant dihydropyridines by several methods led to the selective and facile formation of the corresponding tetrahydropyridines 6 . Furthermore, Mg-promoted hydrosilylation of the N-acetylated product 5a gave C-silylated tetrahydropyridines in a stereoselective manner.

Facile synthesis of silyl enol ethers by Mg-promoted coupling of aliphatic carbonyl compounds with trimethylsilyl chloride

Abstract Treatment of aliphatic carbonyl compounds with trimethylsilyl chloride with Mg turning for Grignard reaction without any pre-treatment in N,N-dimethylformamide at room temperature brought about highly facile, effective and stereoselective coupling to give the corresponding silyl enol ethers in good yields.

Selective and facile electroreductive synthesis of dihydro- and tetrahydropyridine dicarboxylic acid derivatives

Abstract Electroreduction of pyridinedicarboxylic acid derivatives in methanol using a divided cell brought about highly selective hydrogenation to give efficiently the corresponding dihydropyridines in good yields. From the electrolysis of dimethyl 2,3- and 2,5-pyridinedicarboxylates, 1,2-dihydropyridine derivatives were obtained while that of 2,6-, 3,4- and 2,4-disubstituted pyridines afforded the corresponding 1,4-dihydropyridines selectively in good yields.