We initiated our study by exploring the oxidative coupling reaction of (E)-1-phenyl-1-butene (1a) with 4-methoxybenzoic acid (2a), detailed in the Supplementary Material. After an extensive screening process, such as various copper sources, ligands, oxidants, solvents, temperature settings, and light sources, we found that the chiral copper catalyst, with BArF‾ as counter anion, promoted the enantioselective oxidation of the allylic C-H bond of 1a under mild conditions (10 °C, illuminated by 395 nm LEDs). Under the optimal conditions, the reaction yielded the target product 3a with high yield (82%) and excellent enantioselectivity (96:4 enantiomer ratio [er]) (see Table. S1). Control experiments confirmed the necessity of CuCl, ligand L1, NaBArF, di-tert-butyl peroxide (DTBP), and light for the success of the reaction. Among the tested oxidants, DTBP was superior, with others like Selectfluor and N-fluorobenzenesulfonimide (NFSI) yielding low yield and enantioselectivity, or failing to produce the target product at all. Bisoxazoline ligands with bulky substituents enhanced enantioselectivity, with the ligand L1 containing 3,5-di-tert-butylphenyl groups, having the highest enantioselectivity (Table. S1-S4).