Synthesis of Bioactive Nitrogen-Containing Heterocycles via Aryne Methodologies

Abstract

subsequently reacts with another molecule of aryne to form an acridone by extrusion of a molecule of ethylene. 2,3-Dihydroquinolin-4-ones react under the same reaction conditions to afford acridones. This is the first example of ethylene extrusion in aryne chemistry. Scheme 2. The reaction of β-lactam and aryne. Chapter 4 describes a project, which was published in Organic Letters in 2010 3 and in The Journal of Organic Chemistry in 2011 (Scheme 3). 4 This project involves a rapid and efficient synthesis of 2H-indazoles using a [3 + 2] dipolar cycloaddition of sydnones and arynes. A series of 2H-indazoles have been prepared in good to excellent yields using this protocol, and subsequent Pd-catalyzed coupling reactions can be applied to the halogenated products to generate a structurally diverse library of indazoles. This methodology has been highlighted in Synfacts. 5 Scheme 3. The sydnone project. Chapter 5 describes a project soon to be submitted for publication that details a methodology for synthesizing 2H-isoindoles and 9,10-dihydro-9,10-epiminoanthracenes from arynes and münchnones (Scheme 4). 2H-Isoindoles have been generated from arynes and münchnones by a [3 + 2] dipolar cycloaddition process under very mild reaction conditions. Due to the high reactivity of 2H-isoindoles with arynes, 9,10-dihydro-9,10-epiminoanthracenes are ultimately formed in the presence of arynes in good to excellent yields. Scheme 4. The münchnone project. Synthesis of 2H-Indazoles by the [ 3 + 2 ] Dipolar Cycloaddition of Sydnones with Arynes