Mono-ortho-thioquinones, of general formula 1, can be generate under very mild conditions by reacting the corresponding ortho-hydroxythiophthalimides 2 with bases.[1] Species 1, generate in situ, can be trapping through cycloaddition reactions with 1,3-dienes. This chemistry allowed us to study in detail the reactivity of thioquinones 1 and to demonstrate their double behaviour as hetero dienophiles, across the carbon-sulfur double bond, to give the spiro derivates 4 and as hetero dienes leading to the formation of the benzoxathiin derivatives 5.[2] The reagents structure and the reaction conditions chosen make the difference in this reactions driving the interaction between o-thioquinones and 1,3-dienes to the formation of the [2+4] dihydrothiopyran spiro and/or the [4+2] benzoxathiin cycloadducts. A computational study was conduct in order to achieve a deep understanding of both [2+4] and [4+2] paths. [1] a) Capozzi, G.; Menichetti, S.; Nativi, C.; Simonti, C. Tetrahedron Lett. 1994, 35, 9451. b) Capozzi, G.; Falciani, C.; Menichetti, S.; Nativi, C. J.Org. Chem. 1997, 62, 2611. [2] Menichetti, S.; Viglianisi, C. Tetrahedron 2003, 59, 5523.

[2+4] vs [4+2] Cycloaddition Reactions of ortho-Thioquinones with 1,3-Dienes / C. Viglianisi, A. Contini, S. Menichetti. ((Intervento presentato al 22. convegno International Symposium on the Organic Chemistry of Sulfur tenutosi a Saitama nel 2006.

[2+4] vs [4+2] Cycloaddition Reactions of ortho-Thioquinones with 1,3-Dienes

A. Contini;
2006-08-20

Abstract

Mono-ortho-thioquinones, of general formula 1, can be generate under very mild conditions by reacting the corresponding ortho-hydroxythiophthalimides 2 with bases.[1] Species 1, generate in situ, can be trapping through cycloaddition reactions with 1,3-dienes. This chemistry allowed us to study in detail the reactivity of thioquinones 1 and to demonstrate their double behaviour as hetero dienophiles, across the carbon-sulfur double bond, to give the spiro derivates 4 and as hetero dienes leading to the formation of the benzoxathiin derivatives 5.[2] The reagents structure and the reaction conditions chosen make the difference in this reactions driving the interaction between o-thioquinones and 1,3-dienes to the formation of the [2+4] dihydrothiopyran spiro and/or the [4+2] benzoxathiin cycloadducts. A computational study was conduct in order to achieve a deep understanding of both [2+4] and [4+2] paths. [1] a) Capozzi, G.; Menichetti, S.; Nativi, C.; Simonti, C. Tetrahedron Lett. 1994, 35, 9451. b) Capozzi, G.; Falciani, C.; Menichetti, S.; Nativi, C. J.Org. Chem. 1997, 62, 2611. [2] Menichetti, S.; Viglianisi, C. Tetrahedron 2003, 59, 5523.
Settore CHIM/06 - Chimica Organica
[2+4] vs [4+2] Cycloaddition Reactions of ortho-Thioquinones with 1,3-Dienes / C. Viglianisi, A. Contini, S. Menichetti. ((Intervento presentato al 22. convegno International Symposium on the Organic Chemistry of Sulfur tenutosi a Saitama nel 2006.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/175111
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