Pseurotin, a New Metabolite of Pseudeurotium ovalis STOLK Having an Unusual Hetero‐Spirocyclic System. (Preliminary Communication)

The structure and absolute configuration of pseurotin ( 1 ), a new metabolite, isolated from culture filtrates of Pseudeurotium ovalis S TOLK ( Ascomycetes ), has been shown to be 2‐[1′(S), 2′ (S)‐dihydroxhex‐3′‐ene‐yl]‐3‐methyl‐8(S)‐methoxy‐8‐benzoyl‐9(R)‐hydroxy‐(5S)‐1‐oxa‐7‐aza‐spiro[4.4]non‐2‐ene‐4, 6‐dione ( 1 ), by spectral data and chemical transformations, and by X‐ray analysis of its dibromo derivative 2 [1].