An improved synthesis of bicyclo[3.3.0]octane‐2,6‐dione

Abstract

AbstractThe Michael addition of dimethyl malonate (12) to tert‐butyl acrylate (11), carried out without solvent, affords the triester 13a in 88% yield on a kg scale. Selective partial hydrolysis of 13a produces the monoacid 13b almost quantitatively. The Kolbe electrolysis of 13b furnishes the tetraester 7c as a crystalline 1:1 mixture of diastereomers in 62–74% yield. The Dieckmann condensation of 7c is induced by sodium hydride/tert‐butyl alcohol in tetrahydrofuran and yields the enolized β‐oxo ester 8c which, on acidic hydrolysis followed by decarboxylation, produces the title diketone 2 in 90% yield, based on 7c. Thus, the useful diketone 2 is obtained in 46–55% overall yield on a 100‐g scale.