A practical three-step route for C-acylation/deacetylation of acetoacetamides is described. Initial enamination of the acetoacetamides with Boc-monoprotected ethylenediamine provides β-enamino amides, which are acylated at the α-carbon with excellent selectivity. The C-acylated derivatives undergo domino fragmentation in acidic media to give the corresponding β-keto amides accompanied by 2-methyl-4,5-dihydro-1H-imidazole.

A convenient procedure for modification of β-enaminones by α-C-acylation and subsequent acidic cleavage is described. The unsymmetrical β-enamino ketones obtained in this way could be hydrolyzed to provide an entry towards various unsymmetrical 1,3-diketones.

Enaminones, prepared by condensation of homoveratrylamine with 1,3-dicarbonyl compounds, undergo intramolecular cyclization in acidic media to afford 1,1-disubstituted tetrahydroisoquinolines in good yields. Further modification of the title compounds is demonstrated.