The [3 + 3] Cycloaddition Reaction of Trifluoromethyl Alkenes with N-Substituted Pyrrole-2-Carboxaldehydes: Synthesis of Fluorinated 4H-Pyran Derivatives.

A base-promoted [3 + 3] annulation of trifluoromethyl alkenes with N-substituted pyrrole-2-carboxaldehydes has been developed for the synthesis of fluorinated 4H-pyran derivatives. This reaction involves the consecutive cleavage of C-F bonds in the trifluoromethyl and the formation of new chemical bonds without the use of a catalyst. Additionally, this methodology features mild reaction conditions and a good functional group tolerance.