A Convenient Synthesis of Polysubstituted Coumarin‐pyrrolo[2,1‐a]isoquinoline‐1‐carbaldehydes from Isoquinoline, 2‐Bromoacetophenones and Coumarin‐β‐chlorovinyl Aldehydes

Abstract

AbstractIn this research, a simple and efficient strategy for the straightforward synthesis of polysubstituted coumarin‐pyrrolo[2,1‐a]isoquinoline‐1‐carbaldehydes is presented by a sequential three‐component reaction of isoquinoline, 2‐bromoacetophenones and 3‐chloro‐3‐(2‐oxo‐2H‐chromen‐3‐yl)acrylaldehydes as readily available starting materials, which includes base‐mediated 1,4‐addition or [3+2] cycloaddition/intramolecular cyclization/formation two C−C bonds/aromatization tandem reaction under air. In this method, chemoselective cascade process, easily accessible starting materials, energy conserving (short reaction times at room temperature), simplicity of product purification (the products can be purified by washing with EtOH), excellent yields (75–88 %), metal‐free catalyst, green and mild conditions in one‐pot are important highlighted advantages of this protocol.