Visible-light-induced C-H Annulation by Metal-decorated Covalent Organic Frameworks with Fe-bipyridyl linkages

Abstract

The integration of transition metal and photoredox catalyst achieves a harmonious cooperation between sophisticated chemical transformations and judicious utilization of light energy. The previous work was exclusively accomplished through employment of homogeneous transition-metal catalysts or photoredox catalysts. In this study, we present the synthesis of iron-decorated covalent organic frameworks (Fe-COF) and its application on C-H annulation of amides with alkynes by irradiation of visible light. The iron center prompts robust chelation with amides, leading to C-H activation, subsequently. Meanwhile, the photoactive covalent organic framework facilitates visible light absorption and accelerates the C-H activation step. Significantly, isoquinolin-1(2H)-one derivatives with high yield and selectivity were obtained in the presence of Fe-COF under visible light, and highlighting the covalent organic framework's stability and inherent heterogeneous property with repeatable chemical recyclability.