Electronically Mismatched α-Addition of Electron-Deficient Alkenes via Photoinduced Polarity Transduction

Conjugate addition reactions are among the most important transformations in organic synthesis. Electron matching requirements normally restrict the site-selective β-addition of nucleophiles to conjugate acceptors, while regio-reversed α-additions have remained largely elusive. Here we describe a photoinduced polarity transduction strategy that overcomes electronic and steric limitations and enables the exclusively umpolung α-addition of diverse nitrogen nucleophiles to electron-deficient and -neutral alkenes under mild and base-free conditions. This reaction has broad functional group compatibility, shows excellent regioselectivity, and enables late-stage skeletal modification, promising considerable synthetic value. Experimental studies point to a photoinduced through-bond intramolecular charge-transfer (ICT) pathway.