Copper-Catalyzed Chemoselective Hydrogenation of Unsaturated Bonds with Formic Acid/Formate as Hydrogen Donor.

A novel and sustainable strategy, using earth abundant Cu2O as catalyst and biorenewable HCOOH/HCOOK as hydrogen donor for the efficient hydrogenation of multiple unsaturated compounds, including internal and terminal alkynes, ketones, aldehydes, and imines, has been developed to access high-value chemicals with high chemoselectivity. This protocol features operation simplicity, wide substrate applicability, and only CO2 as a byproduct. Additionally, gram-scale experiments and the modification of biologically active molecules all exemplified the synthetic versatility of this protocol.