NHC-Copper-Catalyzed Tandem Hydrocupration and Allylation of Alkenyl Boronates

A tandem hydrocupration/allylation of alkenyl boronates efficiently proceeds with NHC-copper catalysts using hydrosilane and allyl phosphate as reagents. In the presence of IMes-Cu catalyst, the allylation of in situ generated B--copper intermediates smoothly occurs to give homoallylic boronates in high yields, despite competitive side reaction pathways. Mono- and disubstituted alkenyl boronates were effective in the reaction with terminal allyl phosphates, but trisubstituted substrates showed limited reactivity.