Mechanistic Studies on Rh(III)-Catalyzed Defluorinative Annulation of N-Sulfonylarylamides with Ethyl 2-Diazo-3,3,3-Trifluoropropanoates

The synthesis of fluorinated isoquinoline derivatives holds significant value in organic synthesis and medicine. Research into the reaction mechanisms and possible pathways for synthesizing these compounds plays a crucial role in advancing the development and applications of isoquinoline derivatives. Using density functional theory methods, we explored the reaction mechanism and potential pathways of the Rh(III)-catalyzed defluorinative annulation of N-sulfonylarylamides with ethyl 2-diazo-3,3,3-trifluoropropanoates. Theoretical calculations indicate that the reaction initiates with the formation of a metal carbene via C–H activation and denitrogenation, followed by migratory insertion. Subsequent steps involve metal-assisted β-fluoride elimination and anion exchange. Finally, intramolecular cyclization, defluorination, and sulfonyl migration yield isoquinoline products.