The Rich Chemistry Resulting from the 1,3‐Dipolar Cycloaddition Reactions of Enamines and Azides

• Published in: European journal of organic chemistry Vol. 2018; no. 3; pp. 262 - 294
• Main Authors: Bakulev, Vasiliy A., Beryozkina, Tetyana, Thomas, Joice, Dehaen, Wim
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 23.01.2018
• Subjects: Amidines; Azides; Catalysis; Cycloaddition; Enamines; Reaction mechanisms; Transformations; Triazoles; Triazolines
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.201701031

Enamines exhibit exceptionally high reactivity in their 1,3‐dipolar cycloaddition reactions with azides in comparison with other dipolarophiles. This review includes the reactions of various types of enamines with azides of different nature, including catalytic processes. The initial products of the reaction, 1,2,3‐triazolines, are generally unstable and very reactive compounds which are prone to undergo various ring transformations. This provides the background for new synthetic methods and novel reaction types. The formation of a variety of products derived from the reaction of enamines with azides such as mono‐, di‐and tri‐substituted 1,2,3‐triazoles, including N‐unsubstituted derivatives, fused, conjugated and spiro heterocycles, two types of amidines and diaminoalkenes are classified in this review according to the type of stabilization/transformation of the intermediate triazolines. The review includes the reactions of various types of enamines with azides. The initial products of the reaction, triazolines, are very reactive compounds which are prone to undergo various ring transformations giving rich variety of organic compounds.