Bicyclic (amino)(borata)carbene derived from diazadiborinine and isonitrile

The reaction of 1,4,2,5-diazadiborinine (1) with two equivalents of an aryl isonitrile afforded a bicyclic product containing an indole unit (2) or ketenimine moiety (3), suggesting the generation of a B,N-carbene intermediate formed via a [4+2] cycloaddition reaction in the initial step. The employment of the tolyl(phenyl isonitrile)gold complex (PhNCAuTol) as the substrate allowed the bicyclic (amino)(borata)carbene gold complexes (4, 5) to be accessed.