Photoreductive 1,4-Dicarbofunctionalization of 1,3-Enynes with Organoiodides and Cyanoarenes via Halogen-Atom Transfer

A photoreductive halogen-atom transfer (XAT) strategy for 1,4-dicarbofunctionalization of 1,3-enynes with organoiodides and cyanoarenes is disclosed, enabling access to functionalized allenes in a highly regio-, chemo-, and stereoselective manner. Upon the photoredox catalysis and the activation of Et 3 N XAT agents, the mild conditions and high functional group tolerance of this protocol enable the formation of two C–C bonds, including a C(sp 3 )–C(sp 3 ) bond and a C(sp 2 )–C(sp 2 ) bond, in a single reaction step, and provides a general avenue to polysubstituted allenes and late-stage modification of bioactive compounds.