Direct α-C-H Amination Of β-Dicarbonyl Compounds Using DBU-activated N-Haloimides As Nitrogen Sources

α-Amido β-dicarbonyl compounds are versatile building blocks in organic synthesis. They not only constitute versatile intermediates for the synthesis of various heterocyclic compounds, peptide mimetics, a-amino acids and their derivatives, andβ-hydroxyl a-amino esters but also serve as key precursors in the synthesis of a variety of natural products and pharmaceuticals. Therefore they have received the organic chemist and pharmacologist’s great attention. Given the importance ofa-amido β-dicarbonyl compounds, their synthetic methods have been developing rapidly.This paper developed a kind of mild conditions, high conversion rate and practical new way to synthesize the a-amino β-dicarbonyl compounds. At the room temperature, we us the β-dicarbonyl compounds as the substrutes, DBU a as activator,while N-haloimides may act as a self-immolating reagent, the simple and efficient one-pot synthesis of a series of a-amido β-dicarbonyl compounds..Compared with some traditional synthesis method, this method has a broad range of substrates, easy operation and less pollution to the environment. The best reaction conditions are 1equivalents of β-dicarbonyl compounds, 1.5 equivalents of N-halogenatedimide, 1.8equivalents of DBU, acetonitrile as the solvent, under the room temperature. The consequences indicated that whether β-ketone ester, a-acyl ester, or β-dicarbonyl ketone, etc., under this condition can be generated in high yield. But when alkyl substituents of β-dicarbonyl compounds we got 2-amino dihydrogen furan ketone products. Products’ structure through1H-NMR,13C-NMR, high resolution mass spectrometry and single crystal X-ray diffraction characterization, and we also studied the mechanism of this reaction and thought the N-haloimides which actived by DBU could provide a electrophilic bromine species and a potential source of amine. The DBU/N-haloimide protocol provides a novel, mild, and complimentary access toa-imidated- β-dicarbonyl compounds, without the necessity of external nitrogen sources.