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′-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

Loro C.;Papis M.;Nava D.;Brenna S.;Colombo G.;Foschi F.;Broggini G.
2022-01-01

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′-dibenzyl-phenylenediamines as starting substrates. The fluorescence emission properties of these classes of products have been evaluated.
2022
2022
Loro, C.; Molteni, L.; Papis, M.; Beccalli, E. M.; Nava, D.; Presti, L. L.; Brenna, S.; Colombo, G.; Foschi, F.; Broggini, G.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11383/2132537
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