IR of compound from One-pot domino syntheses of 3-alkyl-3-N-substituted aminobenzofuran- 2(3H)-ones based on alkali-promoted Michael addition and lactonization

In this paper, a novel cascade reaction of caesium carbonate-promoted Michael addition and lactonization for the one-pot synthesis of 3-alkyl-3-N-substituted aminobenzofuran-2(3H)-one derivatives has been established based on the screening of the alkaline catalysts and optimization of reaction conditions, in which the N-substituted (ortho-hydroxy) aryl glycine esters were used as the Michael donors to react with different α, β-unsaturated carbonyl compounds. Besides racemic enantiomers, the obtained epimers were successfully separated by conventional chromatography in the case of using the asymmetric raw material. In addition, the possible reaction mechanisms were suggested and the absolute configuration of the epimer was analysed. All the chemical structures of unreported benzofuran- 2(3H)-one derivatives were characterized by IR, ¹H NMR, ¹³C NMR spectra and HRMS spectra.