In situ oxidation of the GaI compound NacNacGa by either N2O or pyridine oxide results in the generation of a labile monomeric oxide, NacNacGa(O), which can easily cleave the C−H bonds of aliphatic and aromatic substrates featuring good donor sites. The products of this reaction are gallium organyl hydroxides. DFT calculations show that these reactions start with the formation of NacNac‐Ga(O)(L) adducts, the oxo ligand of which can easily abstract protons from nearby C−H bonds, even for sp2‐hybridized carbon centers. Aliphatic amines do not enter this reaction for kinetic reasons, presumably because of the unfavorable sterics.
The reactivity of the gallium(I) compound NacNacGa (4) to a variety of unsaturated compounds has been studied. Whereas 4 proved surprisingly unreactive toward olefins, ketones, guanidines, and thioureas, it reacts with isocyanates and carbodiimides to furnish the products of coupling of two heterocumulenes. With isothiocyanate, the CS cleavage occurs, leading to the dimer (NacNacGa) 2 (μ-S)(μ-CNPh) and the cyclization product NacNacGa(S 2 CNPh). These compounds were characterized by multinuclear NMR spectroscopy and X-ray crystal structure analyses. Oxidative addition of SPPh 3 occurs at elevated temperatures and results in the known dimer [NacNacGa(μ-S)] 2 .
Reaction of NacNacGa with azide N3SiMe3 results in the generation of a transient imide NacNacGa(=NSiMe3) that can cleave unactivated sp3C-H and sp2C-H bonds of different substrates, affording gallium amides. Pyridine,...
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 CÀ H activation on the transient alkylidene NacNacGa=CH-SiMe 3 but generates a metallated diazo species NacNacGa(NHN=CHSiMe 3 )(CN 2 SiMe 3 ) ( 13) that further rearranges into the isonitrile compound NacNacGa-(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 BÀ B bond. DFT calculations suggest that the interaction of 9 with N 2 CHSiMe 3 proceeds through intermediate formation of an alkylidene compound that undergoes CH activation with a second molecule of N 2 CHSiMe 3 . Insertion into the BÀ B bond likely proceeds through an initial 1,3-addition of the diborane, followed by boryl migration to the former nitrene center.
In situ oxidation of the Ga I compound NacNacGa by either N 2 Oo rp yridine oxide results in the generation of al abile monomeric oxide,N acNacGa(O), whichc an easily cleave the CÀHb onds of aliphatic and aromatic substrates featuring good donor sites.T he products of this reaction are gallium organyl hydroxides.DFT calculations show that these reactions start with the formation of NacNac-Ga(O)(L) adducts,t he oxol igand of whichc an easily abstract protons from nearby CÀHb onds,e ven for sp 2 -hybridized carbon centers.A liphatic amines do not enter this reaction for kinetic reasons,presumably because of the unfavorable sterics.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.
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