Switchable Multicomponent Cyclization Reactions to Access Fluoroalkylated Dihydropyrimidines and Pyrimidines under Solvent‐Free Conditions.

Comprehensive Summary: The development of switchable solvent‐free multicomponent reactions to build high‐value‐added products is an important demand for organic synthesis. Herein, we detailed the successful implementation of a switchable strategy for the construction of diverse 4‐fluoroalkyl‐1,4‐dihydropyrimidines and 4‐fluoroalkyl‐pyrimidines via a solvent/additive‐free [3 + 2 + 1] annulation, starting from readily available enamines, trifluoroacetaldehyde hydrate or 1‐ethoxy‐2,2‐difluoroethanol and amidines hydrochloride. This reaction conforms to the concept of green synthesis, and provides a new avenue to access valuable fluorinated heterocycles. [ABSTRACT FROM AUTHOR]