Diastereoselective addition of amines to vinyl sulfone modified carbohydrates: a highly flexible methodology for the synthesis of new classes of deoxyaminosugars

Abstract

Methyl 2,3-dideoxy-4,6-O-(phenylmethylene)-3-C-phenylsulfonyl-α-D-erythro-hex-2-enopyranoside (5α) and methyl 2,3-dideoxy-4,6-O-(phenylmethylene)-3-C-phenylsulfonyl-β-D-erythro-hex-2-enopyranoside (5β) have been subjected to Michael addition reaction with various amines to develop a new methodology for the synthesis of new classes of aminosugars. Compound 5α reacted with primary amines to generate gluco- derivatives, but secondary amines produced both gluco- (major) and manno- (minor) isomers. Compound 5β, on the other hand, produced only gluco- isomers with both primary and secondary amines. The stereochemical course of addition of some of the amines to 5α and 5β are significantly different from that of the addition of amines to 3-nitroenopyranoses. The present route to the syntheses of various aminosugars with gluco- configurations from 5α and 5β constitutes a novel method for the introduction of N-monoalkylated and N,N-dialkylated amines to the C-2 carbon of pyranoses in equatorial configurations.