DEVELOPMENT OF MODIFIED PAUSON-KHAND REACTIONS WITH ETHYLENE AND UTILIZATION IN THE TOTAL SYNTHESIS OF (-TAYLORIONE())

Two complementary Pauson-Khand annulation protocols for use with the g aseous alkene, ethylene, are described These N-oxide promoted reaction s (10 examples) are shown to proceed under both mild autoclave conditi ons or, more conveniently, at atmospheric pressure. The developed meth odology has been utilised as the key transformation in the total synth esis of the sesquiterpene (+)-taylorione which has been realised in a good overall yield from readily available (+)-2-carene. Copyright (C) 1996 Elsevier Science Ltd