Facile retro Diels–Alder reaction of a pentamethyltricyclo[5.2.1.0^2,6]decenone derivative: synthesis of (+)-15(S)-prostaglandin A₂

Abstract

The incorporation of methyl groups into the C(1), C(7), C(8), C(9), and C(10) positions of tricyclo[5.2.1.02,6]decenone (1) dramatically accelerates the retro Diels–Alder reaction of (3) under Lewis acid catalysis thus permitting access to synthetic natural prostaglandin A2; the X-ray crystal structure of the ammonium salt of (7) is reported.