A. Contini

D. Pocar

E. Erba

S. Pellegrino

English

AIR Universita degli studi di Milano

1,3 DIPOLAR CYCLOADDITIONS OF AZIDES ON ENAMINES: MORE 
THAN 50 YEARS IN A “CLICK” 
 
 
Emanuela Erba, Alessandro Contini, Sara Pellegrino, Donato Pocar 
 
Dipartimento di Scienze Farmaceutiche, Sezione di Chimica Generale e Organica "A. Marchesini", Università 
degli Studi, Milano-Italy 
 
Pioneering studies on “click” 1,3 dipolar cycloaddition of azides on enamines were reported 
in the early sixties1, although the mechanism has been completely clarified only recently2. 
Depending on the nature of the azide reactant, the triazole cycloadduct can be isolated or can 
quickly decompose to other products. In this last case, the starting enamine drives the 
rearrangement to amidines (Paths A and B, Figure 1) or -amino-imino compounds (Path C, 
Figure 1).  
During the years, this synthetic approach led to different classes of compounds (e. g. nitrogen 
containing heterocycles, enantiopure carboxylic acids, diazoalkanes, chiral cyclic diamines)3 
used in a wide range of applications, from bioactive compounds to hybrid homogenous 
catalysts4. Here, the advances on this click reaction are presented. 
 
 
R1
N
R3
R4R2
N3
X N
N
N
X
R2
NR3
R4
R1
N-
N2
+
X
R2
NR3
R4
R1
N
R2
X
NR3
R4
R1
migration of alkyl group
N
X
NR3
R4
R1
N2
+
-
N
X
R2
R1 N
R3
R4
diazoalkane formation
Path A
migration of amino group
Path B
Path C
+
R2
 
     Figure 1   
 
 
(1) R. Fusco, G. Bianchetti, D. Pocar Gazz. Chim. Ital., 1961, 91, 933–957. 
(2) a) S. Xie et al JACS 2015, 137, 2958-2966; b) A. Contini, E. Erba RSC Advances 2012, 2, 10652–10660. 
(3) a) S. Pellegrino, A. Contini, M. L. Gelmi, L. Lo Presti, R. Soave, E. Erba J. Org. Chem. 2014, 79, 3094-
3102; b) A. Contini, E. Erba, S. Pellegrino Synlett 2012, 23, 1523-1525, c) E. Erba, D. Pocar, P. Trimarco 
Synthesis 2006, 2693-2696, d) F. Cassani, E. Erba, G. Celentano, D. Pocar Synthesis 2004, 1041-1046 e) E. M. 
Beccalli, A. Contini, P. Trimarco Eur. J. Org. Chem. 2003, 3976-3984. 
(4) a) S. Pellegrino, N. Tonali, E. Erba, J. Kaffy, M. Taverna, A. Contini, M. Taylor,D. Allsop, M..L. Gelmi, S. 
Ongeri Chem. Science 2017, 8, 1295-1302; b) S. Pellegrino, G. Facchetti, A. Contini, M. L. Gelmi, E. Erba, R. 
Gandolfi, I. Rimoldi RSC Advances 2016, 6, 71529–71533. 
 


1,3 dipolar cycloadditions of azides on enamines: more than 50 years in a &#8220;Click&#8221;

https://air.unimi.it/bitstream/2434/516367/2/CORRETTO_Abstract%20Posteree.pdf

1,3 dipolar cycloadditions of azides on enamines: more than 50 years in a “Click”

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AIR Universita degli studi di Milano

1,3 dipolar cycloadditions of azides on enamines: more than 50 years in a &#8220;Click&#8221;

Abstract

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Full text

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AIR Universita degli studi di Milano

1,3 dipolar cycloadditions of azides on enamines: more than 50 years in a “Click”