“On water” catalysis: an expeditious approach for the synthesis of quaternary centered 3-hydroxy-3-(nitromethyl)indolin-2-one derivatives

An efficient, eco-friendly “on water” method has been developed for the Henry reaction of isatins with nitromethane to afford 3-hydroxy-3-nitromethylindolin-2-ones. An enhancement in reaction rate was observed “on water” under mild and catalyst-free conditions.