Switchable Chemoselective Transfer Hydrogenations of Unsaturated Carbonyls Using Copper(I) N‑Donor Thiolate Clusters ZhangMeng-Juan TanDa-Wei LiHong-Xi YoungDavid James WangHui-Fang LiHai-Yan LangJian-Ping 2018 Unsaturated alcohols and saturated carbonyls are important chemical, pharmaceutical, and biochemical intermediates. We herein report an efficient transfer hydrogenation protocol in which conversion of unsaturated carbonyl compounds to either unsaturated alcohols or saturated carbonyls was catalyzed by Cu­(I) N-donor thiolate clusters along with changing hydrogen source (isopropanol or butanol) and base (NaOH or K<sub>2</sub>CO<sub>3</sub>). Mechanistic studies supported by DFT transition state modeling indicate that such a chemoselectivity can be explained by the relative concentrations of Cu­(I) monohydride and protonated Cu­(I) hydride complexes in each catalytic system.