Novel stereospecific synthesis of a potential intermediate for preparation of tetracyclic diterpenes from dihydrobenzocyclobutene derivatives

Abstract

A potential intermediate, the ethano-octa-hydromethoxymethylphenanthrenone (12), for the synthesis of tetracyclic diterpenoids has been stereospecifically synthesised by an intramolecular cycloaddition of the o-quinodimethane (10) derived thermally from 5-n-butylthiomethylene-2-[2-(4-methoxydihydrobenzocyclobutenyl)ethyl]-2-methylcyclopentanone, followed by desulphurisation.