Asymmetric Organocatalytic Synthesis of Benzopyran‐ and Benzofuran‐Fused Polycyclic Acetals

Abstract

Abstract An efficient organocatalytic method for the asymmetric preparation of benzopyran‐ and benzofuran‐fused polycyclic acetals is described for the first time. This useful approach includes an interesting tunable Michael–acetalization of nitrostyrenes or α‐aromatization–acetalization of quinones. Under mild conditions, simple cyclic hemiacetals could be stereoselectively converted into four different types of polyheterocycles that serve as scaffolds for a number of bioactive natural products. magnified image