Fig. 5: Scope with respect to cyclic azomethine ylides.

Reactions were performed with 1a (0.10 mmol), 2 (0.12 mmol), P10 (0.01 mmol), and Cs2CO3 (0.60 mmol) in Et2O (2.0 mL) at −20 °C for 72 h; then BF3·Et2O (1.0 mmol) was directly added to the reaction mixture which was further stirred at r.t. for 12 h. Isolated yield. The e.e. value was determined by HPLC analysis on a chiral stationary phase.