CSIRO PUBLISHING - Australian Journal of Chemistry

A Chemoenzymatic and Enantioselective Route to the Tricyclic Frameworks Associated with the Protoilludane and Marasmane Classes of Sesquiterpene

Martin G. Banwell ^A ^B and Gwion J. Harfoot ^A

^A Research School of Chemistry, Institute of Advanced Studies, Australian National University, Canberra ACT 0200, Australia.
^B Author to whom correspondence should be addressed (e-mail: mgb@rsc.anu.edu.au).

Abstract

The enantiomerically pure cis-1,2-dihydrocatechol 3, which is obtained in quantity by microbial dihydroxylation of toluene, has been converted over ten steps, including an initial Diels–Alder cycloaddition reaction, into the tricyclic ketone 12. Direct irradiation of a benzene solution of the latter compound affords a mixture of compounds 13 and 14 which embody the tricyclic frameworks of the sesquiterpene natural products tsugicoline A (1) and isovelleral (2), respectively.

Australian Journal of Chemistry 57(9) 895–897 doi:10.1071/CH04131
Submitted: 13 May 2004 Accepted: 30 June 2004 Published: 1 September 2004