P(═O)R2-Directed Asymmetric Catalytic C–H Olefination Leading to C–N Axially Chiral Targets

Abstract

A novel P(═O)R₂-directed asymmetric catalytic olefination has been developed, enabling efficient access to carbon–nitrogen axially chiral products with excellent yields (up to 92%) and enantioselectivity (up to 99% enantiomeric excess). The synergistic coordination of phosphine oxide functionality and l-pGlu-OH with the Pd metal center, serving as an efficient directing group and chiral ligand, was key to the success of this C–H functionalization system. The reaction demonstrated a broad substrate scope, yielding 33 distinct C–N axial products. The absolute configuration of the products was unambiguously confirmed via X-ray diffraction analysis. Additionally, three representative applications were showcased, involving reduction and oxidation to produce chiral phosphines and related derivatives. A plausible catalytic cycle mechanism has been proposed, supported by detailed experimental studies. Aggregates in the system were identified by aggregation-induced polarization experiments.