The first spontaneous, metal-free, room-temperature hydrogen transfer from ammonia borane to an iminoborane is reported. Mechanistic studies of the reaction indicate a concerted transfer of H and H from donor to acceptor with an activation energy far below those of comparable concerted transfer hydrogenations. This reaction was employed in the syntheses and isolation of new B,N-disubstituted aminoboranes, a comparatively rare subset within the aminoborane family. This successful transfer hydrogenation to a highly dehydrogenated BN system may serve as a starting point for the design of new systems capable of reversible dehydrogenation/rehydrogenation.

We report two rare instances of an insertion into the strong (ca. 170 kcal mol-1) BN triple bond of iminoboranes. In the first, a silylene inserts into di-tert-butyliminoborane to form an iminosilane. In the second, the highly crowded iminoborane Ter-NB-TMP (TMP = 2,2,6,6-tetramethylpiperidyl, Ter = 2,6-(diphenylmethyl)-4-tert-butylphenyl) can be forced to react with Pip-CC-Pip (Pip = piperidyl) at 60 °C. The reaction product is the apparent result of Pip-CC insertion into the iminoborane BN bond.

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Upon complexation to CuOTf, a PMe 3 -stabilized bis(9-anthryl) diborene slowly undergoes an intramolecular hydroarylation reaction at room temperature. Subsequent triflation of the B-H bond with CuOTf, followed by a PMe 3 transfer, finally yields a cyclic sp 2 -sp 3 boryl-substituted boronium triflate salt.By exploiting the Lewis-base stabilization strategy, several neutral diboron compounds with B-B π-bonding have been synthesized recently.