1,3-Stereocontrol in Stereoconvergent Allenylic Alkylation Enabled by Palladium and Chiral Phase-Transfer Cooperative Catalysis

A stereoconvergent allenylic alkylation of allenyl acetates with oxindoles has been established by palladium and chiral phase-transfer cooperative catalysis, allowing for an efficient construction of 1,3-nonadjacent stereogenic elements featuring both central and axial chirality. The noncovalent interactions of PTC create a chiral environment for nucleophilic attack on η³-allylpalladium intermediates. Mechanistic investigations reveal that the Pd/PTC synergistic action and matched chirality are both critical for stereocontrol, while PTC primarily determines the stereoselectivity. Notably, this work represents the first successful implementation of Pd/chiral PTC dual catalysis for 1,3-nonadjacent stereocontrol, thereby enriching the synthetic toolbox for constructing challenging remote stereocenters.