Fig. 2: Substrate scope.

^aReactions were carried out with 7 (0.24 mmol), 8 (0.20 mmol), and 16c (0.004 mmol) in CHCl₃ (2.0 mL) at −50 °C under N₂. The yields shown are for isolated products and the ee values were determined by HPLC analysis. ^bThe reaction temperature is 40 °C.