Cu-catalyzed deoxygenative gem-hydroborylation of aromatic aldehydes and ketones to access benzylboronic esters

A novel copper-catalyzed deoxygenative gem-hydroborylation of aromatic aldehydes and ketones has been developed. This direct and operationally simple protocol provides an effective approach for the synthesis of a variety of primary and secondary benzylboronates, in which broad functional group tolerance was presented. Widely available B2pin2 was used as the boron source and alcoholic proton was applied as the hydride source.