Tetrahedron Report Number 462 - Recent Advances in StereoselectiveC-Glycoside Synthesis

Abstract

Carbohydrate analogs in which a carbon atom substitutes for the glycosidic oxygen are called Cglycosides. During the last two decades, the synthesis of C-glycosides has become an area of intense study among carbohydrate chemists and biochemists because: 1) The discovery of naturally occurring C-nucleosides with important pharmacological properties I gave impetus to synthetic efforts for preparing active carbohydrate analogs; 2) The requirement of C-glycoside chiral building blocks in the synthesis of biologically important macromolecules, such as palytoxin, 2 spongistatin 3,4 and halichondrin B, 5 has stimulated the development of the new synthetic methodologies; 3) C-glycosides are potential inhibitors of carbohydrate processing enzymes and are stable analogs of glycans involved in important intra- and inter-cellular processes. 6-9 C-glycoside synthesis has been reviewed by Postema, 1° Levy, II Sinay, 12 Beau 13 and Nicotra. 6 The aim of the present survey is to provide a summary of the recent applications, published since 1994, of stereoselective methods in the synthesis of C-glycosides. A generalized overview of the most common synthons and intermediates in the C-glycosylation is shown on Scheme 1. The numbers in italics indicate specific sections in this article that describe each synthetic method presented.