Selective one carbon-carbon bond formation reaction of zirconacyclopentadienes with aryl iodides or alkynyl iodides

Reaction of zirconacyclopentadienes with one equiv or two equiv of aryl iodides in the presence of CuCl and DMPU afforded mono-arylated diene derivatives in high yields with high selectivities. Treatment of zirconacyclopentadienes with one equiv of 2-thienyl iodide similarly gave thienyldienes in the presence of CuCl and DMPU, whereas the reaction with two equiv of 2-thienyl iodide produced thienyl iododiene derivatives in high yields. Zirconacyclopentadienes reacted with two equiv of alkynyl iodides to give iododienynes in good yields in the presence of CuCl. This is in sharp contrast to the reaction with two equiv of alkynyl iodides in the presence of CuCl and DMPU which provides dienediynes. (C) 1997 Elsevier Science Ltd. All rights reserved.