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 N2CHSiMe3 affords the nitrilimine compound NacNacGa(N‐NCSiMe3)(CH2SiMe3) (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)(CN2SiMe3) (13) that further rearranges into the isonitrile compound NacNacGa(NHN=CHSiMe3)(N(NC)SiMe3) (15). Reactions of 10 with the silane H3SiPh and the borane HBcat furnished products of 1,3 addition to the nitrilimine moiety NacNacGa{N(ERn)NCSiMe3}(CH2SiMe3), whereas reaction with the diborane B2cat2 gave the product of formal nitrene insertion into the B−B bond. DFT calculations suggest that the interaction of 9 with N2CHSiMe3 proceeds through intermediate formation of an alkylidene compound that undergoes CH activation with a second molecule of N2CHSiMe3. 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. Reaction of diazomethane N2CHSiMe3 with the Ga(I) compound NacNacGa affords the nitrilimine complex 10 that undergoes 1,3‐addition reactions with silane and borane to give products 16 and 17 but an unusual 1,1‐addition of diborane (Bcat)2 (cat=catecholate) to give the diborylamide compound 18. DFT calculations provide insight into the mechanism of formation of compound 9 and 18.