Synthesis of IAN-type N,N-Ligands via Dynamic Kinetic Asymmetric Buchwald–Hartwig Amination

The Pd0-catalyzed coupling of racemic heterobiaryl bromides,
triflates, or nonaflates with aryl/alkyl primary amines using QUINAP
as the ligand provides the corresponding axially chiral heterobiaryl
amines with excellent yields and enantioselectivities. Reactivity
and structural studies of neutral and cationic oxidative addition
intermediates support a dynamic kinetic asymmetric amination mechanism
based on the labilization of the stereogenic axis in the latter and
suggest that coordination of the amine to the Pd center is the stereodetermining
step.