scheme2

Scheme 2. Substrate scope of cyclic N-sulfonyl ketimines 1^a. ^aConditions: 1 (0.10 mmol), 2a (0.15 mmol), and catalyst (0.01 mmol) in CHCl₃(1.0 mL) at 25 °C; ^bIsolated yield; ^cDetermined by ¹H NMR of the crude reaction mixture; ^dThe ee values were determined by chiral HPLC analysis.