Novel Nickel-Catalyzed Reactions of Nitriles with 1,2-Bis(dimethylsilyl)carborane

The nickel-catalyzed reaction of 1,2-bis(dimethylsilyl)carborane (1) with propionitrile afforded an N-silyl enamine. The dehydrogenative double silylation of nitriles without α-H such as isobutyronitrile, benzonitrile, p-tolunitrile, and 1-cyanonaphthalene yielded six-membered cyclic imines. In contrast, the reaction of 1 with 9-anthracenecarbonitrile under the same reaction conditions gave a five-membered N,N-bis(silyl) amine. Interestingly, the reaction of 1 with nitriles having an α-hydrogen such as benzyl cyanide, diphenylacetonitrile, and hydrocinnamonitrile afforded N,N-bis(silyl) enamines.