An unusual gibberellin transannular ketol
Abstract
Spectroscopic evidence is presented for a revised structure for the product obtained by treatment of methyl di-O-acetylgibberellate with zinc and acetic anhydride. It is formed via a Diels–Alder type of addition across the 1(10),2(3)-diene by the carbonyl group of a mixed anhydride between the 19-carboxy and acetic acids.