SYNTHESIS OF FICHTELITE AND RELATED DERIVATIVES OF ABIETANE

Stereoselective routes to fichtelite (18-norabietane, 1a) and its C-4 epimer (19-norabietane, 1b) from abietic acid via abietan-18-oic acid (1c) are described. The latter acid on conversion into 19-nor-4(18)-abietene (3) followed by hydrogenation or hydroboration and reduction yields principally fichtelite, whereas oxidation of the hydroboration product to 18-norabietan-19-al (1h) followed by epimerization and reduction affords 19-norabietane. Similar transformations are reported for ring-C aromatic (8,11,13-abietatriene) analogs, together with nmr spectral correlations and a synthesis of the parent hydrocarbon abietane (1m). © 1969, American Chemical Society. All rights reserved.