Chiral boron Lewis acid-catalyzed asymmetric synthesis of 4,5-dihydropyrrolo[1,2-a]quinoxalines

Abstract

In the presence of B(OMe)3/(R)-BINOL (1 : 1, 10 mol%) and 4 Å molecular sieves, a range of 2-(1H-pyrrol-1-yl)anilines smoothly underwent a Pictet–Spengler-type reaction with aldehydes to give structurally diverse 4,5-dihydropyrrolo[1,2-a]quinoxalines in good to excellent yields and ee.