Asymmetric boron conjugate addition to alpha,beta-unsaturated carbonyl compounds catalyzed by CuOTf/Josiphos under non-alkaline conditions

The asymmetric boron conjugate addition onto alpha,beta-unsaturated ketones and esters has been developed by using the CuOTf/Josiphos complex as the catalyst under non-alkaline conditions. It was found that the addition of MeOH into the reaction system is crucial to the catalytic reactivity. Good to excellent enantio-selectivity (up to 96% ee) and yields (up to 98%) have been achieved for 15 examples.