Selective Formyl Deuteration of Aldehydes by Surface-Enriched Oxygen Vacancy Stabilized Pt on Ceria

Abstract Hydrogen isotope exchange (HIE) is a widely used methodology for deuteration; however, achieving both high isotope abundance and site-selectivity remains challenging for heterogeneous catalysts. Herein, we present a ceria supported platinum catalyst with surface-enriched oxygen vacancy (Ov) that shows impressive formyl deuteration performance with deuterium oxide (D2O) as the deuterium source under hydrogen-free conditions. Using p-methylbenzaldehyde as a model substrate, the typical catalyst achieves >95% deuterium incorporation (D-inc.) at the formyl position while effectively suppressing undesired reductive deuteration pathway. Experimental and theoretical results suggest that the surface-enriched Ov promotes the preferential adsorption of formyl groups on undercoordinated Ce sites, where the local charge redistribution renders the formyl-protons electron-deficient. Simultaneously, the anchored Pt centers effectively catalyze D2O dissociation, generating abundant D* and OD* species. These deuterium species readily interact with the electron-deficient formyl groups, driving hydrogen isotope exchange and forming deuterated aldehydes with high D-formyl selectivity. Substrate scope exploration and gram-scale continuous-flow deuteration experiments demonstrate broad compatibility, revealing its great potential for the selective synthesis of deuterated aldehydes.