Synthesis of Isoxazole and 1,2,3-Triazole Isoindole Derivatives via Silver- and Copper-Catalyzed 1,3-Dipolar Cycloaddition Reaction

M.M. Rammah , W. Gati , H. Mtiraoui , M. El Baker Rammah , K. Ciamala (1) , M. Knorr (1) , Y. Rousselin (2) , M.M. Kubicki (2)

1 UTINAM - Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213)
2 ICMUB - Institut de Chimie Moléculaire de l'Université de Bourgogne [Dijon]

The CuI-or Ag 2 CO 3-catalyzed [3+2] cycloaddition of propargyl-substituted dihydroisoindolin-1-one (3) with arylnitrile oxides 1a-d (Ar = Ph, p-MeC 6 H 4 , p-MeOC 6 H 4 , p-ClC 6 H 4) produces in good yields novel 3,5-disubstituted isoxazoles 4 of the ethyl-2-benzyl-3-oxo-1-((3-arylisoxazol-5yl)methyl)-2,3-dihydro-1H-isoindole-1-carboxylate type. With aryl azides 2a-d (Ar = Ph, p-MeC 6 H 4 , p-OMeC 6 H 4 , p-ClC 6 H 4), a series of 1,4-disubstituted 1,2,3-triazoles 6 (ethyl-2-benzyl-3-oxo-1-((1-aryl-1H-1,2,3-triazol-4-yl)methyl)-2,3-dihydro-1H-isoindole-1-carboxylates) was obtained. The reactions proceed in a regioselective manner affording exclusively racemic adducts 4 and 6. Compared to the uncatalyzed cycloaddition, the yields are significantly improved in the presence of CuI as catalyst, without alteration of the selectivity. The regio-and stereochemistry of the cycloadducts has been corroborated by an X-ray diffraction study of 4a, and in the case of 6a by XH-correlation and HMBC spectra.

Mots clés: [3+2] dipolar cycloaddition; arylnitrile oxides; arylazides; isoxazole; 1; 2; 3-triazoles

Domaines: Chimie

M.M. Rammah, W. Gati, H. Mtiraoui, M. El Baker Rammah, K. Ciamala, et al.. Synthesis of Isoxazole and 1,2,3-Triazole Isoindole Derivatives via Silver- and Copper-Catalyzed 1,3-Dipolar Cycloaddition Reaction. Molecules, 2016, 21 (3), pp.307. ⟨10.3390/molecules21030307⟩. ⟨hal-01292717⟩