Table 3. Enantioselective coupling of indole 2a to aldehydes applying DDQ as the oxidant ^a .

^aPerformed on a 0.10 mmol scale under Ar: 1.0 equiv. 1, 5.0 equiv. 2a, 0.20 equiv. 3f, 1.5 equiv. acid, 1.1 equiv. DDQ (in two portions), and 0.4 mL CH₂Cl₂.

^bReaction stirred for 5 h.