One-step syntheses of substituted 2-pyrrolidinones and 3-pyrrolidinones from α,β-unsaturated diazoketones and amines. Application in the synthesis of barmumycin
作者:Rafael M.P. Dias、Patrícia B. Momo、Antonio C.B. Burtoloso
DOI:10.1016/j.tet.2017.05.040
日期:2017.6
A simple and one-pot way to prepare substituted 2- and 3-pyrrolidinones is described. The method uses unsaturated diazoketones (obtained from aldeydes in a single step) and amines, and provide an easyaccess to these important classes of nitrogen heterocycles. Furthermore, application of this methodology to the synthesis of the natural product barmumycin is achieved in 3 steps from these diazoketones
Highly Efficient and Versatile Synthesis of Lactams and <i>N</i>-Heterocycles via Al(OTf)<sub>3</sub>-Catalyzed Cascade Cyclization and Ionic Hydrogenation Reactions
The discovery and development of an efficient and versatile method for the synthesis of N-substituted lactams is described. Pyrrolindinones, piperidones, and structurally related heterocycles were formed by Al(OTf)3-catalyzed cascade cyclization and ionic hydrogenation reactions of corresponding nitrogen substituted ketoamides in good yields.
Monotrifluoroacetoxyborane-amines, prepared by treating borane-amines with trifluoroacetic acid, have been shown to be efficient reagents for a one-pot, tandem reductive amination/alkylation–cycloamidation of keto or amino acids to achieve the synthesis of 5-aryl or 5-methyl pyrrolidin-2-ones and 6-aryl or 6-methyl piperidin-2-ones.
Fast, Acid-Free, and Selective Lactamization of Lactones in Ionic Liquids
作者:Kristina M. Orrling、Xiongyu Wu、Francesco Russo、Mats Larhed
DOI:10.1021/jo8015264
日期:2008.11.7
A fast and acid-free one-pot 0.2-30 mmol microwave methodology for direct ionic liquid-mediated preparation of lactams from lactones and primary amines has been developed. The protocol was investigated with a wide range of primary amines and a handful of lactones, including substrates with acid-sensitive substituents. Both gamma-lactams and delta-lactams were, despite the complete absence of a Bronsted acid. obtained in useful to excellent yields after only 35 min of microwave processing.