A palladium-catalyzed deuterated formylation of aryl sulfonium salts is prepared conveniently from readily available arenes, which enables the expedient synthesis of a series of structurally diverse C-1 deuterated aldehydes with 96%-99% deuterium incorporation. The easy to handle and cost-effective DCOONa provides a deuterium source, which can be introduced onto the formyl units with excellent selectivity under the palladium-catalytic redox neutral conditions. This catalytic route can accomplish the direct late-stage C-H functionalization of bioactive molecules and natural product derivatives assisted by C (sp)-H thianthrenation. Moreover, on the basis of this practical approach, several deuterated drugs and analogues could be prepared with excellent levels of deuterium incorporation.