Previously, we developed an efficient copper(I)-catalytic system for diastereo- and enantioselective 1,2-addition of 1,1-diborylalkanes to aldimines to afford chiral β-aminoboron compounds that can potentially be used to building blocks of synthetic chemistry. Therefore, We envisaged that the reaction of 1,1-diboryalkanes with ketimines would provide β-aminoboronate esters containing contiguous tetrasubstituted and trisubstituted stereocenters. However, this strategy is challenging because ketimines were knowns to be intrinsically less reactive than aldimines. Herein, we describe a broadly applicable copper catalytic conditions for the diastereo- and enantioselective 1,2-addition of 1,1-diborylalkanes to ketimines. Further transformations that convert the obtained β-aminoboronate esters to synthetically beneficial chiral building blocks are also demonstrated.

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