A Total Synthesis of Galbonolide B

An ester enolate rearrangement/silicon mediated fragmentation cascade was used to convert 7 and 8 into the alcohol 9. The alcohol 9 was converted into the allylic alcohol 12 and then to the ester 14. A further ester enolate rearrangement furnished the stereochemical identity of galbonolide B 1. Base mediated macrocyclization of the acetate ester 16 followed by base mediated alkylation and acetal deprotection gave galbonolide B 1.