Stereoselective synthesis of functionalized allenes from tartaric acid

Abstract

Desymmetrization of the C 2 -symmetric bis -dimethylamide derived from tartaric acid by controlled addition of alkynyl lithium reagents furnished the mono alkynyl ketones which on reduction produced the corresponding propargyl alcohols with good diastereoselectivity. The propargyl alcohols were transformed to allenes using Claisen rearrangement. The formed allenes serve as a precursor for the synthesis of one of the THP units of the natural product sorangicin and for the synthesis of the polyhydroxy unit present in natural product anamarine. • Alkynyl ketones derived from tartaric acid were reduced to yield the corresponding propargyl alcohols with good selectivity (up to dr 90:10). • The propargyl alcohols were transformed to the allenes using microwave mediated Claisen rearrangement. • A masked tetrol and a functionalized tetrahydropyran were prepared using AuCl 3 catalyzed reaction.