A General Approach toL-(+)-Furanomycin and Some Stereoisomers and Analogues Using Furoisoxazoline Intermediates

Abstract

An unexpectedly stable, isolable enol ether epoxide is the key intermediate in a new, efficient synthesis of the antibiotic L-(+)-furanomycin (3; a natural α-amino acid) and a group of analogues. The furo[2,3-d]isoxazoline 1 and its diastereomer result from cycloaddition of methylfuran to a glyceronitrile oxide, serving as a chiral glycine equivalent; epoxidation of 1 then affords the stable enol ether epoxide 2. Concise subsequent reactions of 1 and 2 lead to 3, its 5-epimer, and structural analogues of 3.