Noncatalytic on water aldol reaction of isatins with cyclic 1,3-diketones at room temperature without the need for subsequent chromatography

Noncatalytic on water aldol transformation of isatins and cyclic 1,3-diketones results in substituted 3-hydroxy-3-(2-hydroxy-6-oxocyclohex-1-en-1-yl)indolin-2-ones in 87–98% yields. Optimized conditions have been found and a mechanistic rationale for the reaction has been deduced. The new efficient and facile process represents a convenient way to compounds with the 3-hydroxyindolin-2-one and 3-hydroxycyclohex-2-en-1-one moieties.