Aqueous Extract of Sapindus mukorossi Fruit Pericarp‐Mediated One‐Pot Synthesis of Spiro[indoline‐3,4′‐pyran]‐2‐one Derivatives

Abstract

Natural surfactants are biodegradable and therefore environmentally benign. To avoid the detrimental effects of synthetic surfactants on the environment, it is highly desirable to replace them with natural surfactants as alternatives. In this context, we are reporting herein the use of saponins derived from Indian soapberry (Sapindus mukorossi) fruit pericarp as a natural surfactant for the synthesis of spiro[indoline‐3,4′‐pyran]‐2‐one derivatives through one‐pot three‐component reaction of isatins, malononitrile, and cyclic 1,3‐dicarbonyl compounds. Wide substrate scope has been established with the synthesis of as many as 18 compounds in yields ranging from 72% to 94%.