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Article: A computational study of the 1,3-dipolar cycloaddition reaction mechanism for nitrilimines (1).
- Article from:
- Canadian Journal of Chemistry
- Article date:
- September 1, 2005
- Author:
CopyrightCOPYRIGHT 2005 NRC Research Press. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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Introduction
The addition of a 1,3-dipole, a system of three atoms over which four [pi] electrons are distributed, to a dipolarophile, typically an alkene or alkyne, is the most commonly used synthetic method for forming five-membered heterocyclic molecules. The mechanism for these [3+2] reactions has been the subject of numerous articles and remains an open problem in physical organic chemistry (1-7). Originally, Huisgen (8-10) proposed a concerted, single-step mechanism with the two new bonds partially formed at the transition state, akin to that for the Diels-Alder cycloaddition. Shortly thereafter, an alternative two-step mechanism involving a biradical ...