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 N₂ CHSiMe₃ affords the nitrilimine compound NacNacGa(N-NCSiMe₃ )(CH₂ SiMe₃ ) (10). Carrying out this reaction in the presence of pyridine does not lead to C-H activation on the transient alkylidene NacNacGa=CHSiMe₃ but generates a metallated diazo species NacNacGa(NHN=CHSiMe₃ )(CN₂ SiMe₃ ) (13) that further rearranges into the isonitrile compound NacNacGa(NHN=CHSiMe₃ )(N(NC)SiMe₃ ) (15). Reactions of 10 with the silane H₃ SiPh and the borane HBcat furnished products of 1,3 addition to the nitrilimine moiety NacNacGa{N(ER_n )NCSiMe₃ }(CH₂ SiMe₃ ), whereas reaction with the diborane B₂ cat₂ gave the product of formal nitrene insertion into the B-B bond. DFT calculations suggest that the interaction of 9 with N₂ CHSiMe₃ proceeds through intermediate formation of an alkylidene compound that undergoes CH activation with a second molecule of N₂ CHSiMe₃ . Insertion into the B-B bond likely proceeds through an initial 1,3-addition of the diborane, followed by boryl migration to the former nitrene center.