Borane-Catalyzed Selective Hydrosilylation of Internal Ynamides Leading to beta-Silyl (Z)-Enamides

Abstract

We have developed a borane-catalyzed regio- and stereoselective hydrosilylation of internal ynamides for the first time. The scope of ynamide substrates and silane reactants was broad under mild reaction conditions, affording synthetically versatile beta-silyl (Z)-enamide products. The observed stereoselectivity was reasoned to be due to the beta-silicon effect on a postulated, ketene iminium intermediate.