1, 3‐Dipolar Cycloaddition of Alkanone Enolates with Azides in Deep Eutectic Solvents for the Metal‐Free Regioselective Synthesis of Densely Functionalized 1, 2, 3‐Triazoles. Issue 36 (22nd September 2022)

• Record Type: Journal Article
• Authors: Cicco, Luciana; Perna, Filippo Maria; Falcicchio, Aurelia; Altomare, Angela; Messa, Francesco; Salomone, Antonio; Capriati, Vito; Vitale, Paola
• Is Part Of: European journal of organic chemistry. Volume 2022:Issue 36(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-09-22
• Subjects: Cycloadditions -- Deep Eutectic Solvents -- Enolates -- Green chemistry -- Nitrogen heterocycles; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.202200843
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract: An eco‐friendly metal‐free protocol was developed for the regioselective synthesis of densely functionalized 1, 2, 3‐triazoles through a 1, 3‐dipolar cycloaddition reaction of alkanone enolates with azides performed in the environmentally responsible choline chloride/urea or choline acetate/urea eutectic mixture. This approach displays a broad substrate scope, straightforwardly furnishing the desired triazoles (including the challenging phenolic derivatives) in yields of up to 98 %, while working at room temperature and under aerobic conditions. The practicability of the method is exemplified by the sustainable synthesis of some pharmaceutically relevant triazole derivatives carried out via telescoped, one‐pot cycloaddition/reduction processes in the same eutectic mixture without any halfway isolation/purification step of intermediates. Abstract : The 1, 3‐dipolar cycloaddition reaction between alkanone enolates and azides proceeds smoothly and regioselectively in eco‐friendly eutectic mixtures to yield densely functionalized 1, 2, 3‐triazoles. Pharmacologically active triazoles have also been targeted directly in DESs via telescoped, one‐pot cycloaddition/reduction processes.