Fig. 3: Substrate scope of indolyl-substituted exocyclic quinolin-2(1H)-ones.

Reaction conditions: 3 (0.2 mmol), 4 (0.1 mmol), (DHQD)₂PYR (20 mol%), DME (1.0 mL), -10 °C, 72 h. Then, iron powder (1.0 mmol), AcOH (1.0 mL), 30 °C for 8 h. Isolated yield, the ee values were determined by chiral high performance liquid chromatography (HPLC).