Montmorillonite Catalyzed Tandem Synthesis of 1,1,3-Trisubstituted-1H-Isochromenes from 3-Phenylisochromenones

Abstract

An efficient synthesis of 1,1,3-trisubstituted-1H-isochromenes, 3 is reported from isochromen-1-ones, 1 and Grignard Reagents, 2a-h through sequential Grignard reactions/acid-catalyzed cyclization. The cyclization underwent smoothly with montmorillonite K10 catalyst to obtain the 1,1,3-trisubstituted-1H-isochromenes in excellent yields.

Keywords:

• Grignard reaction
• montmorillonite K10 clay 1,1,3-trisubstituted-1H-isochromenes

Acknowledgments

We gratefully acknowledge the management Vellore Institute of technology for their support of this research. We also thank the Indian Institute of Science and IIT madras for spectroscopic support.