Synthesis of Benzofuran‐fused 1,4‐Dihydropyridines <i>via</i> Bifunctional Squaramide‐catalyzed Formal [4+2] Cycloaddition of Azadienes with Malononitrile

Abstract

Abstract An efficient bifunctional squaramide‐catalyzed Michael addition/cyclization of azadienes with malononitrile has been successfully developed, providing a facile access to chiral benzofuran‐fused 1,4‐dihydropyridines with excellent yields, wide substrate scope and up to 99% ee. Additionally, this formal [4+2] cycloaddition can be performed in gram scale without noticeable loss of yield and enantioselectivity.