To reproduce this ligand engineering with the VLAO method, we calculated eight TSs of the borylcupration according to Ito's computational analysis (Figure ). These TSs correspond to eight reaction routes of borylcupration, where an olefine (1-butene) approaches to the Cu-B bond from any of the four directions (denoted by A, B, C or D) to give either the branched product 7 or the linear product 8 (denoted by subscript b or l). Out of the four routes to give the branched product, Ab and Db give the major enantiomer (S)-7, whereas Bb and Cb afford the minor enantiomer (R)-7. The regio-and enantioselectivity of the reaction are determined by the relative energies of these TSs, and the branch selectivity (bs) and enantiomeric excess (ee) can be estimated as follows: