Synthesis of 5-Fluoro-dihydroindolizines from Pyrrole-2-acetic Acids and Trifluoromethyl Alkenes via Dual C-F Bond Cleavage in a CF 3 Group.

Herein, we describe the synthesis of 5-fluoro-dihydroindolizines via dual C-F bond cleavage in a trifluoromethyl group. The photocatalytic defluorinative coupling of pyrrole-2-acetic acids and α-trifluoromethyl alkenes cleaved the first C-F bond, providing gem -difluoroalkenes bearing an unprotected pyrrole motif. Subsequently, an intramolecular S N V reaction closed the ring by forming a C-N bond concomitantly with the cleavage of the second C-F bond. Using indole-2-acetic acids as the substrates, the reactions also allow the assembly of 6-fluoro-dihydropyrido[1,2- a ]indoles.