Chemistry of cage-shaped hydrocarbons. Reactions of pentacyclo[6.6.0.02,6.03,13.010,14]tetradecane-4,11-diene

Abstract

A formal synthesis of peristylane 1 and oxaperistylane 3 are accomplished through chemical modifications of a cage-shaped molecule pentacyclo[6.6.0.0^2,6.0^3,13.0^10,14]tetradecane-4,11-diene 2. Reaction of 2 with NBS resulted in the formation of two dibromides 7 and 9 and a bromohydrin 8. Compound 9 was derived from 8 through bromination followed by a transannular ring closure. Epoxidation of 2 with MCPBA produced an epoxide 15 and a diepoxide 13, both with the oxygen atoms oriented on the exo-side of the rings. Hydroboration of 2 followed by oxidation yielded a mixture of three isomeric diketones 20, 21 and 22. Oxaperistylane 3 was obtained from 21 by two successive reduction reactions. Peristylane 1 can be prepared from 22 by a known procedure. The structures of 9 and 20 were characterized by single crystal X-ray diffraction analyses.