Photocatalytic Transfer Hydrogenation Reactions Using Water as the Proton Source

Transfer hydrogenation using liquid hydrogen carriersas the directproton sources under mild conditions has received extensive attentionin the research area of organic synthesis. The emerging photocatalyticwater-donating transfer hydrogenation (PWDTH) is a promising alternativeover the conventional hydrogenation technology due to the advantagesof being eco-friendly. This paper focuses on the recent advances inthe rising and rapidly developing field of PWDTH reactions, devotedto elucidating the mechanism of the hydrogen transfer process andrationalizing the design principles of efficient photocatalysts. Finally,the current challenges and future opportunities are described.