An isolable gallium-substituted nitrilimine and its reactivity with B-H, Si-H and B-B bonds.

Reaction of the Ga(I) compound NacNacGa ( 9 ) with the diazo compound N 2 CHSiMe 3 affords the nitrilimine compound NacNacGa(N-NCSiMe 3 )(CH 2 SiMe 3 ) ( 10 ). Carrying out this reaction in the presence of pyridine does not lead to C-H activation on the transient alkylidene NacNacGa=CHSiMe 3 , but generates a metallated diazo species NacNacGa(NHN=CHSiMe 3 )(CN 2 SiMe 3 ) ( 13 ) that further rearranges into the isonitrile compound NacNac- Ga(NHN=CHSiMe 3 )(N(NC)SiMe 3 ) ( 15 ). Reactions of 10 with the silane H 3 SiPh and the borane HBcat furnished products of 1,3 addition to the nitrilimine moiety NacNacGa{N(ER n )NCSiMe 3 }(CH 2 SiMe 3 ), whereas reaction with the diborane B 2 cat 2 gave the product of formal nitrene insertion into the B-B bond. DFT calculations suggest that the interaction of 9 with N 2 CHSiMe 3 proceeds via intermediate formation of an alkylidene compound that undergoes CH activation with a second molecule of N 2 CHSiMe 3 . Insertion into the B-B bond likely proceeds via an initial 1,3-addition of the diborane, followed by boryl migration to the former nitrene center.