Intramolecular homolytic substitution of sulfinates and sulfinamides: a computational study

Kyne, Sara H. and Aitken, Heather M. and Schiesser, Carl H. and Lacote, Emmanuel and Malacria, Max and Ollivier, Cyril and Fensterbank, Louis (2011) Intramolecular homolytic substitution of sulfinates and sulfinamides: a computational study. Organic and Biomolecular Chemistry, 9 (9). pp. 3331-3337. ISSN 1477-0520

Full content URL: http://dx.doi.org/10.1039/c1ob05043e

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Abstract

Ab initio and density functional theory (DFT) calculations predict that intramolecular homolytic substitution by alkyl radicals at the sulfur atom in sulfinates proceeds through a smooth transition state in which the attacking and leaving radicals adopt a near collinear arrangement. When forming a five-membered ring and the leaving radical is methyl, G3(MP2)-RAD//ROBHandHLYP/ 6-311++G(d,p) calculations predict that this reaction proceeds with an activation energy (E1) of 43.2 kJ mol-1. ROBHandHLYP/6-311++G(d,p) calculations suggest that the formation of five-membered rings through intramolecular homolytic substitution by aryl radicals at the sulfur atom in sulfinates and sulfinamides, with expulsion of phenyl radicals, proceeds with the involvement of hypervalent intermediates. These intermediates further dissociate to the observed products, with overall energy barriers of 45-68 kJ mol-1, depending on the system of interest. In each case, homolytic addition to the phenyl group competes with substitution, with calculated barriers of 51-78 kJ mol-1. This computational study complements and provides insight into previous experimental observations.

Keywords:Density functional theory calculations, Homolytic substitution, Sulfinamides, Sulfinates
Subjects:F Physical Sciences > F160 Organic Chemistry
F Physical Sciences > F190 Chemistry not elsewhere classified
Divisions:College of Science > School of Chemistry
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ID Code:17617
Deposited On:09 Jun 2015 08:46

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