Ortho-thioquinones are reactive intermediates that efficiently react with various electron-rich dienophiles in inverse electron-demand Diels-Alder reactions, leading to the formation of 1,4-benzoxathiin cycloadducts.1 In this way several biologically interesting derivatives have been prepared with complete control of regiochemistry in one-step under mild conditions.1 Since Diels-Alder reactions represent one of the most important route for the construction of helicenes2 we decided to verify the possibility of using ortho-thioquinones as key intermediates for the construction of heterohelicenes. We designed and synthesized an ortho-fused tricyclic system able to react as electron-rich bis-dienophile with several ortho-thioquinones, in turn obtained in situ from the corresponding ortho-hydroxythiophthalimide precursors under mild conditions. The optimization of the reaction conditions, the regio- and relative stereochemical features of the cycloaddition as well as the opportunity to control also the absolute stereochemistry of this new synthesis of heterohelicenes will be the topic of this communication. 1) J. Org. Chem. 1997, 62, 2611-2615. 2) Chem. Rev. 2012, 112, 1463-1535.
27th International Symposium on Organic Chemistry of Sulfur, Jena, Germany, 24-29 July 2016 / Viglianisi, Caterina; Menichetti, Stefano; Tofani, Lorenzo. - STAMPA. - (2016), pp. 148-148. (Intervento presentato al convegno 27th International Symposium on Organic Chemistry of Sulfur “From fundamental research to application“ tenutosi a Jena, Germany nel 24-29 July 2016.).
27th International Symposium on Organic Chemistry of Sulfur, Jena, Germany, 24-29 July 2016.
VIGLIANISI, CATERINA;MENICHETTI, STEFANO;TOFANI, LORENZO
2016
Abstract
Ortho-thioquinones are reactive intermediates that efficiently react with various electron-rich dienophiles in inverse electron-demand Diels-Alder reactions, leading to the formation of 1,4-benzoxathiin cycloadducts.1 In this way several biologically interesting derivatives have been prepared with complete control of regiochemistry in one-step under mild conditions.1 Since Diels-Alder reactions represent one of the most important route for the construction of helicenes2 we decided to verify the possibility of using ortho-thioquinones as key intermediates for the construction of heterohelicenes. We designed and synthesized an ortho-fused tricyclic system able to react as electron-rich bis-dienophile with several ortho-thioquinones, in turn obtained in situ from the corresponding ortho-hydroxythiophthalimide precursors under mild conditions. The optimization of the reaction conditions, the regio- and relative stereochemical features of the cycloaddition as well as the opportunity to control also the absolute stereochemistry of this new synthesis of heterohelicenes will be the topic of this communication. 1) J. Org. Chem. 1997, 62, 2611-2615. 2) Chem. Rev. 2012, 112, 1463-1535.I documenti in FLORE sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.