The [3 + 3] Cycloaddition Reaction of Trifluoromethyl Alkenes with <i>N</i> -Substituted Pyrrole-2-Carboxaldehydes: Synthesis of Fluorinated 4 <i>H</i> -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 4 H -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.