Interestingly, ligand L9 that incorporates a tert-butyl group at the para-position of the phenyl ring of the oxazoline scaffold afforded (R)-4a in 47% yield with slightly improved enantioselectivity (89% ee). Use of ligand L10, the enantiomer of L9, could also furnish the cross-coupled product (S)-4a with analogous results. Finally, control experiments confirmed that no desired three-component crosscoupling reaction occurred in the absence of copper catalyst or ligand (Table ). Interestingly, the reaction still proceeded smoothly to afford (S)-4a in slightly improved the yield without erosion of the enantiopurity without visible light irradiation (68% yield, 90% ee).