Unified Strategy for Iodine(III)-Mediated Halogenation and Azidation of 1,3-Dicarbonyl Compounds
作者:Marc J. Galligan、Ramulu Akula、Hasim Ibrahim
DOI:10.1021/ol403504z
日期:2014.1.17
A mild and rapid (diacetoxyiodo)benzene-mediated formal electrophilic alpha-azidation of 1,3-dicarbonyl compounds using commercially available Bu4NN3 as the azide source is reported. The reaction conditions employed are based on optimization studies conducted on the analogous halogenations with Et4NX (X = Cl, Br, 1).
The direct azidation of various heterocyclic beta-ketoesters, lactones, and lactams is reported. By using tosylazide and an organic base such as L-proline or TBD, the direct alpha-insertion of azide into these substrates was achieved in moderate to good yields, without competitive deacylating diazo transfer. This procedure represents an interesting alternative to the usual two-step approach of alpha-halogenation and subsequent displacement with azide ion. (C) 2009 Elsevier Ltd. All rights reserved.
Guanidinium iodide/urea hydrogen peroxide-catalyzed azidation of β-dicarbonyl compounds with trimethylsilyl azide
We present an efficient synthesis of α-azido-β-dicarbonyl compounds from β-dicarbonylcompounds and trimethylsilyl azide, catalyzed by guanidinium hypoiodite. The reaction can be run in air at ambient temperature (up to 40 °C) and is not sensitive to moisture. The substrate scope is broad, including cyclic and linear β-dicarbonylcompounds, and the α-azide products are obtained in 55%–99% yield.