Selection of the conditions for the sequential reaction. Two prerequisites are needed in order to control the configuration of the stereogenic centers formed by sequential transformations involving a switchable asymmetric catalyst: i) different reaction rates for the two catalytic transformations, and ii) rapid and full inversion of the enantiomeric state of the catalyst. In the present copper-catalyzed transformation of VPnone, the HS and HA steps can be performed fully independently by adding the amine transfer reagent after completion of the HS step. We thus monitored the consumption of VPnone under the optimized conditions reported in Table , entry 2 but in the absence of Amine-tBu (Figure ). We found out that VPnone is fully consumed in ca. 12 minutes and that (R)-VPnol is formed in ca. 70% yield and 63% ee; EPnol (ca. 12%) is detected as the main byproduct (Figure ). Upon comparing NMR traces for the HS only reaction and the concomitant HS/HA process, it appears that the rate of the ketone reduction is drastically higher in the latter case, i.e. that HS of the ketone function occurs more rapidly when Amine-tBu is present from the beginning in the catalytic mixture (Figure ). We also noticed that the ee in VPnol measured during this HS reaction (63%) is slightly lower than the ee1 determined for HS step in the concomitant HS/HA process towards APnol (68-71% ee, Table ). The ee of VPnol, isolated from this concomitant process, is of 68%, consistently with the latter point (Figure ). This discrepancy in the catalytic performance provided by the Cu─H helical catalyst between the HS only reaction and the concomitant HS/HA process suggests different catalytic active species for the ketone reduction depending whether the amine transfer reagent is present or not. This is not detrimental for the implementation of a sequential HS/HA reaction since side reaction at the vinyl moiety remains limited (≈12% of EPnol is formed) and the ee of the HS step is only marginally reduced.