Enantioselective α‐Allylation of Acyclic Esters Using B(pin)‐Substituted Electrophiles: Independent Regulation of Stereocontrol Elements through Cooperative Pd/Lewis Base Catalysis

Cooperation between a Lewis base and Pd catalyst enables the direct enantioselective α‐functionalization of aryl and vinyl acetic acid esters using a bifunctional B(pin)‐substituted electrophile. Critical to the success of this method was the recognition that both catalysts could control the necessary stereochemical aspects; the Lewis base catalyst controls the enantioselectivity of the reaction, whereas the Pd catalyst regulates alkenyl‐B(pin) configuration. This is the first example of using cooperative catalysis to control both stereochemical features during Pd‐catalyzed allylic alkylation. A cooperative‐catalysis‐based Lewis base/Pd method for the direct α‐functionalization of Pfp aryl and alkenyl acetates using a B(pin)‐substituted allyl mesylate electrophile is reported. Critical to the success of this method was the recognition that both catalysts could control the necessary stereochemical aspects; the Lewis base catalyst controls the enantioselectivity of the reaction, whereas the Pd catalyst regulates alkenyl B(pin) configuration.