Isolation and Structure of Pseurotin A,a Microbial Metabolite of Pseudeurotium ovalis STOLK with an Unusual Heterospirocyclic System

The structure and absolute configuration of pseurotin A, a new metabolite, isolated from culture filtrates of Pseudeurotium ovalis STOLK (Ascomycetes) has been shown to be (1′S, 2′S, 5S, 8S, 9R, 3′Z)-8-benzoyl-2 (1′,2-dihydroxy-3′-hexenyl)-9-hydroxy-8-methoxy-3-methyl-1-oxa-7-azaspiro 4,4]non-2-ene-4,6-dione ( 1 ).