Encouraged by these results, we systematically evaluated the influence of the other reaction parameters in the presence of UL1 (Scheme 3A). A solvent switch from i-PrOH/TFE to i-PrOAc/TFE significantly improved the enantioselectivity to 92.5:7.5 (Scheme 3A, Entry 3). In contrast, when nheptane/TFE was used as the solvent, the yield of 3 could be increased to 66% (Scheme 3A, Entry 4).