Formation and Metallomimetic Reactivity of a Transient Dicoordinate Alkylborylene.

While existing literature has primarily focused on carbene-stabilized amino- and arylborylenes of the form [(carbene)BR] (R = substituent), herein we report the generation and metallomimetic reactivity of the first carbene-stabilized alkylborylene [(CAAC)BCy] (CAAC = 1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene, Cy = cyclohexyl). Furthermore, the transition metal-like decarbonylation reactions of a borylene complex, [(CAAC)BCy(CO)], derived from borylene [(CAAC)BCy] and CO, are described. Additional findings described include i) the identification of the coordination stages of the ligand to boron towards forming complexes [(CAAC)BCyL] in the reduction route from starting material [(CAAC)BCyBr] and in the photolysis route from carbonyl complex [(CAAC)BCy(CO], and ii) insights from quantum-chemical computations regarding the molecular and electronic structure of the borylene at various stages.