Highly Regio- and Diastereoselective Synthesis of CF₃‑Substituted Lactones <i>via</i> Photoredox-Catalyzed Carbolactonization of Alkenoic Acids

Trifluoromethylative lactonization of both terminal and internal alkenoic acids by photoredox catalysis has been developed. The use of a Ru photocatalyst and Umemoto’s reagent as a CF3 source is key in the present carbolactonization. This is the first example of a highly endo- and diastereoselective synthesis of CF3-substituted five-, six-, and seven-membered ring lactones from internal alkenoic acids.