Organocatalyzed Enantioselective Allylation of Isatins by Using a Chiral Amino Alcohol Derived Squaramide as Catalyst

Abstract A series of new squaramide‐based organocatalysts were synthesized from commercially available 3,4‐dimethoxycyclobut‐3‐ene‐1,2‐dione in two steps. A 2.5 mol‐% loading of the organocatalyst successfully catalyzed the asymmetric allylation of isatins with allyltributyltin to give the corresponding 3‐allyl‐3‐hydroxyoxindoles in high yields and enantioselectivities (up to 98 % ee).