Biosynthesis of Xenovulene A®: formation of a cyclopentenone via a unique ring expansion–ring contraction mechanism

Abstract

Incorporation studies with ¹³C-labelled acetates and methionine in Acremonium strictum indicate that the cyclopentenone moiety in Xenovulene A^® is formed via a unique pathway in which a C-methylated phenolic precursor undergoes ring expansion to a tropolone followed by two successive ring contractions resulting in incorporation of the C-methyl carbon into the five-membered ring.