Density functional theory computations reveal mechanistic insights into Cu and chiral phosphoric acid (CPA) catalyzed enantioconvergent amination of racemic benzenesulfonohydrazide. The OÀ O bond homolysis of tert-butyl 4phenylbutaneperoxoate was found to be the turnover-limiting step with a total free energy barrier of 19.1 kcal/mol. The enantioconvergent amination is realized to obtain the same intermediate through prochiral carbon atom. The order and mode of hydrogen atom transferred by CPA and tert-butyloxy have a significant influence on the enantioselectivity and energy barriers. The olefinic side product generated by βhydride elimination is 9.9 kcal/mol thermodynamically less favourable. A series of phosphoric acids are predicted as promising co-catalysts with lower barriers for OÀ O bond homolysis.