A dimerization/cyclization reaction of 2-benzylamino-phenols for the direct synthesis of the oxazolo-phenoxazine skeleton is reported. The reaction occurs under copper catalysis in the presence of hypervalent iodine(III), giving selectively the 5H-oxazolo[4,5-b]phenoxazine compounds. The cascade process, which allows the conversion of the substrates into the tetracyclic products, involves three C-H functionalization steps. Initial oxidation of electron-rich arenes by the hypervalent iodine is essential for the dimerization of substrates, whereas the formation of the five-membered rings is promoted by the copper species. 1-Benzyl-2-phenyl-6-(aryl-benzyl)amino-benzimidazoles are regioselectively obtained using N,N & PRIME;-dibenzyl-phenylenediamines as starting substrates. The fluorescence emission properties of these classes of products have been evaluated.

Direct Synthesis of Fluorescent Oxazolo-phenoxazines by Copper-Catalyzed/Hypervalent Iodine(III)-Mediated Dimerization/Cyclization of 2-Benzylamino-phenols / C. Loro, L. Molteni, M. Papis, E.M. Beccalli, D. Nava, L.L. Presti, S. Brenna, G. Colombo, F. Foschi, G. Broggini. - In: JOURNAL OF ORGANIC CHEMISTRY. - ISSN 0022-3263. - 87:2(2022 Jan), pp. 1032-1042. [10.1021/acs.joc.1c02329]

Direct Synthesis of Fluorescent Oxazolo-phenoxazines by Copper-Catalyzed/Hypervalent Iodine(III)-Mediated Dimerization/Cyclization of 2-Benzylamino-phenols

L. Molteni
Secondo
;
E.M. Beccalli;D. Nava;L.L. Presti;F. Foschi
Penultimo
;
2022-01

Abstract

A dimerization/cyclization reaction of 2-benzylamino-phenols for the direct synthesis of the oxazolo-phenoxazine skeleton is reported. The reaction occurs under copper catalysis in the presence of hypervalent iodine(III), giving selectively the 5H-oxazolo[4,5-b]phenoxazine compounds. The cascade process, which allows the conversion of the substrates into the tetracyclic products, involves three C-H functionalization steps. Initial oxidation of electron-rich arenes by the hypervalent iodine is essential for the dimerization of substrates, whereas the formation of the five-membered rings is promoted by the copper species. 1-Benzyl-2-phenyl-6-(aryl-benzyl)amino-benzimidazoles are regioselectively obtained using N,N & PRIME;-dibenzyl-phenylenediamines as starting substrates. The fluorescence emission properties of these classes of products have been evaluated.
Catalysis; Cyclization; Dimerization; Oxazines; Phenols; Copper; Iodine
Settore CHIM/06 - Chimica Organica
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/904090
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