New Catalyst for the Efficient and Selective Beta-Hydrosilylation of Acrylonitrile. Effect of Ultrasound

摘要

While there is an abundance of catalysts that are useful in promoting the addition of the Si-H bond across alkenes and alkynes, relatively few agents efficiently catalyze the hydrosilylation of acrylonitrile. In particular, catalysts that lead to exclusively Beta-addition to the double bond in acrylonitrile are rare and generally give low yields. These include tertiary amines, platinum on carbon, Raney nickel, amides, and phosphines. The two most effective catalysts are a three-component system (CuCl/n-Bu3N/N,N,N',N'-tetramethylethylene-diamine (TMEDA) developed by Bluestein which requires temperatures of 50-126 C for 40 h to give 75% yields of Beta-adduct (7.5:1:1.2 mol ratio of reactants/CuCl/amines) and a binary system of a copper compound (Cu2O, CuCl, or Cu(acac)2) and an isocyanide developed by Svoboda et al., which requires heating to 120 C for 2 h to give 70-75% yields of Beta-adduct (9:0.1:0.3 mol ratio of reactants/Cu catalysts/isocyanide). Reprints. (jes)