fig2

Figure 2. Optimization of the reaction conditions^a. ^aReaction conditions: pre-catalyst (20 mol%), base (1.5 equiv), 1a (0.1 mmol), and 2a (0.12 mmol) in solvent (1.5 mL). ^bIsolated yield. ^cDetermined by chiral HPLC analysis. ^d5Å molecular sieves (10 mg) were used as an additive at room temperature. ^epre-catalyst (10 mol%). ^fThe temperature was 0 °C. ^gThe temperature was 35 °C. ^hTHF = 3 mL. ⁱTHF = 1 mL. Mes = 2,4,6-trimethylphenyl.