Synthesis of enaminones
Simple and direct nucleophilic addition of secondary amines to 1,2,3-triazine under mild reaction conditions cleanly provides β-aminoenals in good yields. The reaction proceeds by amine nucleophilic addition to C4 of the 1,2,3-triazine, in situ loss of N2, and subsequent imine hydrolysis.
R. E. Quiñones, C. M. Glinkerman, K. Zhu, D. L. Boger, Org. Lett., 2017, 19, 3568-3571.
Ceric ammonium nitrate catalyzes the reaction between aromatic or aliphatic primary amines and a variety of β-dicarbonyl compounds, including β-ketoesters, β-ketothioesters and β-diketones to give β-enaminones in good to excellent yields at room temperature in short reaction times.
V. Sridharan, C. Avendaño, J. Carlos Menéndez, Synlett, 2007, 2133-2142.
Mechanochemical grinding in the presence of KHSO4 and SiO2 enables a facile amination of solid 1,3-dicarbonyl compounds with ammonium salts or amines in solid state to yield the corresponding β-imino derivatives in high yields. The method has the advantage of simple manipulation and mild conditions.
S.-L. Xu, C.-P. Li, J.-H. Li, Synlett, 2009, 818-822.
The coupling of acid chlorides with terminal alkynes using one equivalent of triethylamine under Sonogashira conditions followed by subsequent addition of amines or amidinium salts to the intermediate alkynones allows a straightforward access to enaminones and pyrimidines under mild conditions and in excellent yields.
A. S. Karpov, T. J. J. Müller, Synthesis, 2003, 2815-2826.
A Au(I)-catalyzed tandem amide addition and Meyer-Schuster rearrangement enables the synthesis of enamides from primary amides and propargyl aldehydes. Enamide stereochemistry was controlled simply by changing solvents and adding a catalytic amount of acid.
S. M. Kim, D. Lee, S. Hyeok Hong, Org. Lett., 2014, 16, 6168-6171.