Extended Data Fig. 4: Summary table for rapid identification of the desired chiral ligand and reaction conditions for enantioconvergent copper-catalyzed N-alkylation of aliphatic amines.

This copper-catalyzed N-alkylation reaction has excellent scopes for both the alkyl halide and the amine parts; however different types of ligands were still required to achieve high enantioselectivity and reactivity. Generally speaking, alkyl halides predominantly determined the ligand choice; by contrast, amines had limited impact on the ligand choice. Specifically, small secondary alkyl chlorides such as 2-chloropropanamide required sterically congested ligand L*4 or L*5 for good enantioselectivity. For bulkier secondary alkyl chlorides with large α-alkyl or -aryl substituents, sterically less congested tridentate ligand L*7 or L*10 or bidentate ligand L*8 performed the best. Regarding the bulkiest tertiary alkyl chlorides, planar tridentate ligand L*9 with a likely more opened catalyst pocket was necessary for maintaining good reaction efficiency and enantioselectivity. Within the same series of alkyl chlorides, minor ligand changes such as from L*4 or L*7 to L*5 or L*10, respectively, might deliver slightly boosted enantioselectivity.