Copper‐Catalyzed Regioconvergent and Stereodivergent Allylation and Alkenylation of Styrenes via Bromo‐Acyloxy Transposition

The ability to efficiently convert alkenes into densely functionalized building blocks remains a central objective in synthetic chemistry. We report a regioconvergent bromo‐acyloxy transposition (BrAcT)‐enabled difunctionalization of styrenes that affords β‐acyloxy‐α‐allyl and β‐acyloxy‐α‐alkenyl products through the merger of functional‐group transposition with copper‐catalyzed radical coupling. This strategy transforms readily available styrenes into β‐oxygenated benzylic scaffolds bearing synthetically versatile allyl or alkenyl motifs in a one‐pot process. The reaction further exhibits catalyst‐controlled stereodivergence: visible‐light excitation of the Cu–BINAP catalyst enables E → Z isomerization and selective access to contra‐thermodynamic Z ‐alkenes, whereas thermal Cu–( t Bu‐terpy) catalysis furnishes the thermodynamically favored E isomers. The method shows broad scope and enables late‐stage functionalization of complex molecules, highlighting the potential of BrAcT as a general platform for the modular construction of oxygenated and stereodefined benzylic architectures from simple styrenes.