A simple, straightforward, and highly
efficient pseudo-three-component
one-pot synthesis of a series of pharmaceutically interesting functionalized
3,3-bis(indol-3-yl)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.