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. |