Metabolites of bird's nest fungi. Part 12. Studies on the biosynthesis of the cyathins

Abstract

The cyathins are a group of diterpenoids of unique structure which are produced by bird's nest fungi of the family Cyathus. Biosynthetic studies utilizing [1-13C], [2-13C], and [1,2-13C2]acetate indicate that 11-O-acetylcyathatriol, produced by the fungus C. earlei, is formed from acetate via the isoprenoid pathway. The labelling experiments are consistent with a route involving cyclization–rearrangement of geranylgeranyl pyrophosphate as shown in Schemes 1 and 3.