Biomass‐Derived Cu‐Catalyzed General C—X (X = C, N, O) Bond Formation: Carbenoid Insertion Reactions of C—H, N—H, O—H Bond and Late‐stage Functionalization of Drug Molecules^†

Comprehensive Summary The development of sustainable and efficient catalytic systems for the formation C—C, C—N, C—O bonds is a fundamental goal in modern synthetic chemistry. We present a biomass‐derived Cu/Chitosan‐800 catalyst that facilitates a range of carbenoid insertion reactions into C—H, N—H, and O—H bonds. This catalyst demonstrates remarkable activity, enabling the functionalization of diverse substrates, including the late‐stage modification of drug molecules with up to 95% yield and good recyclability. Our findings highlight the catalyst's potential in advancing environmentally friendly chemical transformations, offering a promising tool for pharmaceutical synthesis and organic synthesis.