Total synthesis of d,l-coronafacic acid by an intermolecular Diels–Alder approach

Abstract
An efficient total synthesis of d,l-coronafacic acid (2) has been achieved from 4-cyclopentene-1,3-dione (4). The synthesis involves keto ester 7 as a key intermediate that is conveniently prepared by the Diels–Alder addition of enedione 4 to ethyl 4-ethyl-2,4-pentadienoate (5).