Atom-efficient synthesis of BN-heterocycles from oligoboranes and isonitriles

Abstract

O-xylyl isonitrile readily inserts into one of the B–B bonds of simple, unactivated linear peraminotri- and tetraboranes. Subsequent thermal rearrangements yield two different types of CB2N heterocycles, a 1-azonium-2,4-diboretane-3-ide and a 1,2,4-azadiboretidine, respectively. When heated with a second isonitrile equivalent, these generate 1,3,2-diazaboroles (C2BN2) and an unsymmetrical 1,4,2,5-diazadiborinine (C2B2N2).