Recent Advances in the Construction of Allylic All‐Carbon Quaternary Stereocenters via π‐Allyl Metal Intermediates

ABSTRACT All‐carbon quaternary stereogenic units are prevalent structural motifs in natural products and pharmaceutical molecules. Due to the immense steric hindrance arising from four carbon substituents, their catalytic asymmetric synthesis has remained a focal point and a significant challenge. Transition‐metal‐catalyzed asymmetric allylation serves as a direct and efficient strategy for constructing such architectures. Through the π‐allyl metal intermediate generated by transition‐metal activation of allylic reagents, this approach enables the introduction of nucleophiles to the allylic position with high regio‐ and stereoselectivity, thereby successfully establishing the target stereocenters. This review systematically summarizes recent advances in the construction of allylic all‐carbon quaternary stereocenters via π‐allyl metal intermediates. It focuses specifically on asymmetric allylic alkylation and cycloaddition reactions, along with their applications in the synthesis of natural products and pharmaceuticals, concluding with an outlook on future developments.