Photoredox catalytic cyclization of aryl enones in the presence of visible light, promoted either by metals or organic dyes, represent a valuable strategy for the synthesis of cycloalkanes. The development of a stereoselective version of such transformation, in the presence of the metal-free catalyst Eosin Y was studied, with the aim to realize an efficient protocol for the in-flow synthesis of enantiomerically enriched functionalized cyclopentane rings, taking advantage of the flow reactors technology. The use of a chiral auxiliary on the bisenone to be cyclized offers a straightforward and convenient option to exert a stereocontrol on the light-driven cyclization. By exploiting Evans’ oxazolidinones, the stereoselective light-driven cyclization affords, after the removal of the chiral auxiliary, a functionalized 1,2-trans cyclopentane ring in up to 83/17 enantiomeric ratio. When the reaction was performed in continuo, in a homemade coil photoreactor, high yields were observed. The cyclization was also successfully realized in a 3Dprinted mesoreactor, without any change in the diastereoseletctivity of the process.

Stereoselective Visible-Light Catalyzed Cyclization of Bis(enones) : A Viable Approach to the Synthesis of Enantiomerically Enriched Cyclopentane Rings / F. Medici, S. Resta, P. Presenti, L. Caruso, A. Puglisi, L. Raimondi, S. Rossi, M. Benaglia. - In: EUROPEAN JOURNAL OF ORGANIC CHEMISTRY. - ISSN 1434-193X. - 2021:32(2021), pp. 4521-4524. [10.1002/ejoc.202100397]

Stereoselective Visible-Light Catalyzed Cyclization of Bis(enones) : A Viable Approach to the Synthesis of Enantiomerically Enriched Cyclopentane Rings

F. Medici;A. Puglisi;L. Raimondi;S. Rossi;M. Benaglia
2021

Abstract

Photoredox catalytic cyclization of aryl enones in the presence of visible light, promoted either by metals or organic dyes, represent a valuable strategy for the synthesis of cycloalkanes. The development of a stereoselective version of such transformation, in the presence of the metal-free catalyst Eosin Y was studied, with the aim to realize an efficient protocol for the in-flow synthesis of enantiomerically enriched functionalized cyclopentane rings, taking advantage of the flow reactors technology. The use of a chiral auxiliary on the bisenone to be cyclized offers a straightforward and convenient option to exert a stereocontrol on the light-driven cyclization. By exploiting Evans’ oxazolidinones, the stereoselective light-driven cyclization affords, after the removal of the chiral auxiliary, a functionalized 1,2-trans cyclopentane ring in up to 83/17 enantiomeric ratio. When the reaction was performed in continuo, in a homemade coil photoreactor, high yields were observed. The cyclization was also successfully realized in a 3Dprinted mesoreactor, without any change in the diastereoseletctivity of the process.
Chiral auxiliary, Flow reactors; Photoredox; Stereoselectivity; Visible Light-driven reactions
Settore CHIM/06 - Chimica Organica
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/871198
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