Sterically Tolerant Nickel-Catalyzed Borylation of Aryl Triflates, Vinyl Triflates, and Vinyl Acetates

Organoboron compounds are indispensable intermediates in modern synthetic chemistry, yet efficient and general methods for their preparation from sterically hindered electrophiles remain limited. Herein, we report a sterically tolerant nickel-catalyzed borylation of aryl and vinyl triflates/acetate using bis(pinacolato)diboron (B2pin2) as the boron source. Building on our previous studies of nickel/B2pin2-promoted reductive transformations, we developed a catalytic system that enables the efficient conversion of structurally diverse aryl triflates, including sterically congested 2,6-disubstituted substrates, to the corresponding boronic esters under mild conditions. Extension of the strategy to vinyl triflates and inert vinyl acetates was achieved under modified conditions. Overall, this work provides a practical and cost-effective alternative to precious-metal-catalyzed methods and expands access to sterically hindered organoboron building blocks from readily available triflate precursors.