Chiral building blocks for amphotericin B

Abstract

A general plan is outlined for disconnection of the polyene macrolides, which is aimed at achieving their syntheses, as well as facilitating the determination of their absolute configurations. The plan is exemplified by amphotericin B, I, the only family member of known absolute configuration. The major chiral component is a 20-carbon chain, III, which upon further retrosynthetic disconnection leads to three subunits, two of which correspond to the dideoxy hexoses IV and V. Although these are formally mirror images, they are best represented as the 3,4-dideoxyhexopyranoside, 1, and the 3,5-dideoxyfuranose, 2. Syntheses of 1 and 2 from readily available starting materials are described.