Facile and One-Pot Access of 3,3-Bis(indol-3-yl)indolin-2-ones and 2,2-Bis(indol-3-yl)acenaphthylen-1(2H)-one Derivatives via an Eco-Friendly Pseudo-Multicomponent Reaction at Room Temperature Using Sulfamic Acid as an Organo-Catalyst

A simple, straightforward, and highly efficient pseudo-three-component one-pot synthesis of a series of pharmaceutically interesting functionalized 3,3-bis(indol-3yl)indolin-2-ones (3a-3w) and 2,2-bis(indol-3-yl)acenaphthylen-1(2H)-one derivatives (5a-5d) has been developed based on a low-cost and environmentally benign commercially available sulfamic acid as an organo-catalyst in aqueous ethanol at room temperature. The salient features of the present protocol are mild reaction conditions, excellent yields, high atom-economy, eco-friendliness, easy isolation of products, no column chromatographic separation, and reusability of reaction media.