A cobalt covalent organic framework: a dual-functional atomic-level catalyst for visible-light-driven C–H annulation of amides with alkynes

Abstract

The merger of transition-metal catalysis and photoredox catalysis enables a balance between elegant chemical transformation and the rational use of light energy. Previously, it was always accomplished with the two types of homogeneous catalysts: transition-metal catalysts and photoredox catalysts. Herein, we report a synthesis of a dual-functional cobalt covalent organic framework (CoCOF-SYNU-1) for visible-light-driven C–H annulation of amides with alkynes. An atomic-level cobalt center ensures the occurrence of powerful chelation with amides and subsequent precise C–H activation, while the photoactive covalent organic framework is responsible for absorbing visible light to accelerate the catalytic cycle. In the presence of CoCOF-SYNU-1, visible-light-driven regioselective [4 + 2] C–H annulation proceeded smoothly, delivering a wide range of isoquinolin-1(2H)-one derivatives with high efficiency. Significantly, due to the inherent heterogeneous nature and good stability of CoCOF-SYNU-1, the reaction exhibits excellent catalyst recyclability and practicability.