SILICON-CONTROLLED CARBON-CARBON BOND FORMATION AND CYCLIZATION BETWEEN CARBONYL-COMPOUNDS AND ALLYLTRIMETHYLSILANE

The effect of silicon on C-C bond formation between carbonyl compounds and allyltrimethylsilane was investigated. Treatment of 1,3-diketones , beta-ketoesters or malonates with allyltrimethylsilane in the presen ce of ceric ammonium nitrate (CAN) in methanol produced the correspond ing allylated products. Furthermore, introduction of Mn(OAc)3 . 2H(2)O into those reactions for replacement or assistance of CAN afforded si licon-containing cyclopentanes in 51-75% yields. A sequential process involving allylation, free-radical cyclization and elimination was als o developed by use of CAN/Mn (OAc)(3) . 2H(2)O/Cu(OAc)(2) . H2O. Accor dingly, beta-ketoesters or malonates were allowed to react with allyls ilanes in acetic acid to give silicon-containing cyclopentanes with an exo methylene unit in 52-71% yields. These reactions involved carboca tionic and carboradical intermediates, of which formation and chemical activities were controlled by a beta-silyl group. (C) 1997 by John Wi ley & Sons, Ltd.