Kinetics and mechanism of the 1,3-dipolar
cycloaddition of nitrilimine with thione-containing
dipolarophile: a detailed DFT study
S. Ali Beyramabadi
Mohammad Reza Bozorgmehr
Received: 28 October 2015 / Accepted: 16 January 2016 / Published online: 28 January 2016
Ó Springer Science+Business Media Dordrecht 2016
Abstract The 1,3-dipolar cycloadditions are extensively used for the preparation
of ﬁve-membered heterocycles. A mechanism consisting of two pathways was
proposed for production of two regioisomers of the 1,3-dipolar cycloaddition of the
nitrilimine and a thione-containing dipolarophile. Here, we have investigated the
kinetics and mechanism of this reaction using density functional theory. Two
possible mechanisms of A and B have been investigated in which Cl
is present in
the structure of the nitrilimine reactant in the case of mechanism A, while it is
absent in the case of mechanism B. Mechanism A, involving Cl
, has higher barrier
energy than mechanism B, and so is rejected. Mechanism B involves two pathways,
I and II, which lead to two regioisomers with different percentages in the products.
Both of the pathways are one-step. Pathway II involves the attack of the nitrogen
atom of the nitrilimine on the carbon atom of the C=S group of the dipolarophile.
The product of pathway II is kinetically and thermodynamically a more favorable
product than its regioisomer produced in the other pathway. The obtained results are
in agreement with the experimental results.
Keywords 1,3-Dipolar cycloadditions Á Regioisomer Á DFT calculations Á PCM Á
Kinetics Á Mechanism
Electronic supplementary material The online version of this article (doi:10.1007/s11164-016-2449-3)
contains supplementary material, which is available to authorized users.
& S. Ali Beyramabadi
Department of Chemistry, Mashhad Branch, Islamic Azad University, Mashhad, Iran
Res Chem Intermed (2016) 42:6125–6141