A zinc boryl compound unlocks diverse reactivity pathways beyond nucleophilic borylation

Abstract

Borylation chemistry plays a crucial role in the development of new synthetic methodologies. However, the reactivity of zinc-boryl species has not been fully explored, particularly in relation to diverse reaction pathways. Here we show that a zinc-boryl species is successfully synthesized from bis(catecholato)diboron, exhibiting amphiphilic reactivity. This compound acts as a nucleophilic boron anion with methyl iodide and as an electrophile with N,N’-dicyclohexylcarbodiimide, facilitating zinc-boron bond dissociation and generating zinc-carbon and zinc-nitrogen bonds while cleaving carbon-nitrogen double bonds. The enhanced reactivity is likely due to the stronger covalency of the zinc-boron bond. Additionally, the zinc-boryl compound promotes the catalytic diborylation of azobenzene, underscoring its versatility as a reactive intermediate. Density functional theory studies illuminate the electronic structure and reactivity of the zinc-boron bond, providing insights into potential applications in synthetic chemistry.