Cu(I)-mediated intramolecular conjugate addition of alkenyltrimethylstannane functions to alpha,beta-unsaturated ketones: A convenient preparation offunctionalized cis-fused bicyclo[4.3.0]non-8-en-3-ones and bicyclo[3.3.0]oct-6-en-3-ones

A new copper(I)-mediated method for effecting intramolecular conjugate addi tion of alkenyl functions to alpha,beta-unsaturated ketone systems is repor ted. Treatment of the substrates 14, 15, 19-21, 22 and 23 with 2.5 equiv. o f CuCl in DMF at room temperature affords excellent yields of the correspon ding bicyclic ketones 24, 25, 29-31, 32 and 33. On the other hand, treatmen t of substances 15-18 with CuCN in DMSO at 60 degrees C provides good-to-ex cellent yields of the corresponding bicyclic products 25-28. (C) 2000 Elsev ier Science Ltd. All rights reserved.