Metabolic products of microorganisms. Part 262. The absolute configuration of sphydrofuran, a widespread metabolite from streptomycetes

Abstract

AbstractSphydrofuran (1) was isolated from the culture filtrate of Streptomyces sp. (strain Gö 28 and Tü 3616) by chemical screening methods. Metabolite 1 is an anomeric and ring‐chain tautomeric mixture and could easily be transformed into the stable furan derivative 2 under acidic conditions. The constitution and relative configuration of 1 was established by X‐ray crystallography of its 8‐O‐methyl derivative 3a. The absolute configuration at C(4) of 1 and thus of the whole molecule (3R,4S,5S) could be determined starting from 2 using the Helmchen method.