New Entry to a Three-Component Pyrimidine Synthesis by TMS−Ynones via Sonogashira Coupling

TMS−ynones are versatile synthetic equivalents of β-keto aldehydes and can be readily synthesized in an atom-economical fashion by coupling (het)aroyl chlorides and (TMS)−acetylene with only one equiv (!) of triethylamine under Sonogashira conditions. This mild ynone synthesis is also a suitable entry to 2,4-disubstituted pyrimidines in the sense of a one-pot three-component reaction, i.e., a coupling−addition−cyclocondensation sequence.