Catalyst-free synthesis of 3-hydroxy-3-(alkyl/aryl)indolin-2-ones by addition of organoaluminum reagents to isatins

An efficient synthesis of 3-hydroxy-3-(alkyl/aryl)indol-2-one derivatives has been described by the reactions of isatin with organoaluminum reagents. The reaction is very rapid and yields are high. The protocol is applicable for substituted isatins as well as a variety of organoaluminums.