A theoretical study on cycloaddition reactions between [c]-annelated heterocyclic five-membered dienes and acetylene

Dinadayalane, T. C. ; Punnagai, M. ; Sastry, G. Narahari (2003) A theoretical study on cycloaddition reactions between [c]-annelated heterocyclic five-membered dienes and acetylene Journal of Molecular Structure: Theochem, 626 (1-3). pp. 247-262. ISSN 0166-1280

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Official URL: http://www.sciencedirect.com/science/article/pii/S...

Related URL: http://dx.doi.org/10.1016/S0166-1280(03)00105-2

Abstract

B3LYP/6-31G∗ calculations were done on a series of [c]-annelated carbo- and heterocyclic five-membered dienes and their cycloaddition transition state structures and products with acetylene as dienophile. While the reactions of cyclobutano[c]- and cyclobuteno[c]- fused five membered rings are to be categorized as traditional [4+2] cycloadditions, those of benzo[c]-fused five-membered rings are best described as [8+2] cycloaddition reactions. High exothermicities of products of 3X are to be traced directly to the formation of an aromatic benzenoid ring. In contrast, the formation of antiaromatic cyclobutadiene moiety hinders the feasibility of the reactions with 2X dienes. The computed percentage of bond length stretching/shortening of the important bonds, frontier orbital analysis, the quantum of charge transfer from diene to dienophile at the transition state and deformation energies were used to corroborate the reactivity of masked dienes.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Cycloadditon Reactions; Activation Energies; Reaction Energies; Masked Dienes; Density Functional Method
ID Code:106614
Deposited On:28 Jul 2017 09:31
Last Modified:28 Jul 2017 09:31

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