Silylene- and Germylene-Mediated C−H Activation: Reaction with Alkanes, Ethers, and Amines

The reaction of silylene Si[N 2 ( t Bu) 2 C 2 H 2 ] and Ph−X (X = I, Br) in alkane and ethereal solvents results in the formation of C−H activation product [C 2 H 2 ( t Bu 2 )N 2 ]SiRI and an equivalent of benzene or oxidative-addition product [C 2 H 2 ( t Bu 2 )N 2 ]SiPhI. The ratio of products obtained is dependent upon substrate and concentration. This class of reaction has been extended for Si[N 2 ( t Bu) 2 C 2 H 2 ] and Ge[CH(SiMe 3 ) 2 ] 2 to alkylamines. The primary kinetic isotope effect has been measured for the reaction of Si[N 2 ( t Bu) 2 C 2 H 2 ] with Et 2 O and determined to be k H /k D = 5.1 ± 0.1. The reaction of Ge[CH(SiMe 3 ) 2 ] 2 and Ph−Br with THF was determined to be second order. A large isotope effect ranging from 1.8 to 1.1 was measured for a variety of deuterated aryl halides, consistent with an initial electron transfer to the aryl halide.