SILICON-CONTROLLED ALLYLATION OF 1,3-DIOXO COMPOUNDS BY USE OF ALLYLTRIMETHYLSILANE AND CERIC AMMONIUM-NITRATE

A new method was developed for allylation of 1,3-diketones, beta-keto esters, and malonates. Treatment of those 1,3-dioxo compounds with allyltrimethylsilane (1.3 equiv) in the presence of eerie ammonium nitrate (2.1 equiv) in methanol at room temperature often gave the mono-C-allylated products in good to excellent yields (74-98%). These reactions, involving beta-carboradical and beta-carbocationic intermediates, were controlled by a silyl group. Replacement of eerie ammonium nitrate and methanol with manganese(III) acetate (2.4 equiv) and acetic acid afforded silicon-containing dihydrofurans in high yields at 80 degrees C.