Studies on intramolecular alkylation. II. The preparation of intermediates for diterpene synthesis by intramolecular carbenoid addition reactions

Abstract

A new method is described for the preparation of tricyclic compounds containing the 3,2,1- and 2,2,2-bicyclooctane ring systems. The copper-catalysed decomposition of the diazomethyl ketones derived from the olefinic acids (7), (9), (18), and (19) afforded, respectively, the cyclopropyl ketones (12), (13), (21), and (20). These compounds were transformed into the cyolopropyl diketones (15) and (22) which by treatment with dilute acid or base gave, in turn, the bridged octalones (1) and (2).