Combining (CH₂O)_<i>n</i> and (NH₄)₂CO₃ as a Formamidine Equivalent for “Four-in-One” Synthesis of Fluoroalkylated 2-<i>H</i>-Pyrimidines

Multicomponent reactions hold the potential to maximize the synthetic efficiency in the preparation of diverse and complex molecular scaffolds. An unprecedented formal [3+1+1+1] annulation approach for the one-step synthesis of fluoroalkylated 2-<i>H</i>-pyrimidines commencing from perfluoroalkyl alkenes, paraformaldehyde, and ammonium carbonate is described. By harnessing readily accessible (CH₂O)<i>_n</i> and cheap (NH₄)₂CO₃ as a formamidine surrogate, this method effectively replaces traditionally preformed amidines with a pyrimidine assembly. The multicomponent reaction proceeds in a step-economical, operationally simple, metal-free, and additive-free manner, featuring a broad substrate scope, excellent functional group compatibility, and scalability. The potential for the synthetic elaboration of the obtained 2-<i>H</i>-pyrimidine is further demonstrated in the alkylation and vinylation of its C2 position.