Cobalt-catalyzed regiodivergent hydrofunctionalization of allenes

Abstract

A regiodivergent cobalt-catalyzed addition of nucleophiles to allenes has been developed under mild conditions. The cobalt-catalyzed hydrocarboxylation of allenes can generate trisubstituted enol esters with the help of dppe in up to 96% yields and with exclusive E-selectivity. In the presence of acetic acid, Co/dppbz-catalyzed addition of carbon nucleophiles to allenes affords the branched-allylic products in up to 95% yield and with regioselectivity above 20 : 1. This methodology indicates that cobalt exhibits different reactivities as the same group rhodium and iridium in allene hydrofunctionalization.