N-Heterocyclic Carbene-Catalyzed Mannich Reaction for the Synthesis of β-Amino Ketones: N, N-Dimethylformamide as Carbon Source

The efficiency of N,N-dimethylformamide (DMF) in the N-heterocyclic carbene-catalyzed Mannich reaction for the synthesis of beta-amino ketones has been demonstrated. This strategy involves oxidative coupling of aryl methyl ketones and 2-aminopyridines in the presence of DMF. The reaction does not require pre-functionalization of the substrates, thus making it a practically applicable approach for the generation of beta-amino ketones. The reaction requires the use of tin(II) chloride dihydrate (SnCl2 center dot 2H(2)O) as Lewis acid in the presence of tert-butyl hydroperoxide (TBHP) as the oxidant. The reaction was tolerant to several aryl methyl ketones, including 2-acetylnaphthalene and acetylthiophene. Various substituted 2-aminopyridines react with acetophenone to give the desired beta-amino ketones in good yields.