All-in-one Rh(iii)-covalent organic framework for sustainable and regioselective C(sp2)–H bond functionalization†

Abstract

Rh(III)-catalyzed regioselective C(sp²)–H bond functionalization is a facile tool for precisely synthesizing valuable organic molecules. However, challenges such as cost, reusability, and metal residue issues are always encountered in pharmaceutical applications under homogeneous reaction conditions. Herein, we report the synthesis of a Rh(III)-covalent organic framework (RhCOF-SYNU-1) for heterogeneous regioselective C(sp²)–H bond functionalization. The suitable post-modification and metal immobilization endow RhCOF-SYNU-1 with multiple characteristics, including adaptable and homo-dispersed Rh(III) centers, an extended conjugation system, and considerable stability. Hence, RhCOF-SYNU-1 serves as an all-in-one catalyst by integrating the roles of transition-metal catalyst, photocatalyst, and metal-center ligand. It also demonstrates excellent catalytic performance in various visible-light-driven or thermal regioselective C(sp²)–H bond functionalization reactions. Notably, the inherent robustness of RhCOF-SYNU-1 ensures its long-term use and simultaneous recycling with Cu oxidant under sophisticated organic reaction conditions, constituting a beneficial strategy for sustainable Rh(III) catalysis.