Fig. 2: Coumarin Sope^a–c.

^aUnless otherwise noted, reaction conditions: 1 (0.1 mmol), 2a (0.12 mmol), C6 (20 mol%), in CHCl₃ (1 mL) and O₂ as an oxidant. ^bIsolated yield, ^cer calculated by Chiral HPLC.