Decatungstate Catalyzed Synthesis of Trifluoromethylthioesters from Aldehydes via a Radical Process.

Here we report a mild and general method for the trifluoromethylthiolation of aldehydes using N-trifluoromethylthiosaccharin as the CF3S radical source and sodium decatungstate (NaDT) as the photocatalyst. This reaction proceeds via hydrogen atom abstraction by photoactivated DT and features good functional groups and substrate tolerance. Generally, electron-rich aldehydes demonstrate better reactivity than electron-deficient ones and good selectivity is observed for the trifluoromethylthiolation of aldehydic C-H bonds over tertiary and benzylic C-H bonds. Preliminary mechanistic studies have shown that a free radical process is involved.