Cu(I)-Catalyzed Synthesis of Dihydropyrimidin-4-ones toward the Preparation of β- and β³‑Amino Acid Analogues

A copper­(I)-catalyzed synthesis of substituted dihydropyrimidin-4-ones from propargyl amides via the formation of ketenimine intermediate has been successfully developed; the synthesis afforded good isolated yields (80–95%). The mild reaction conditions at room temperature allow the reaction to proceed to completion in a few hours without altering the stereochemistry. Further, by involving a variety of reactive nucleophiles, the obtained substituted dihydropyrimidin-4-ones were elegantly transformed into the corresponding β- and β3-amino acid analogues.