Chiral bis(oxazoline) ligands are used for the first time to promote the enantioselective vanadium-catalyzed oxidation of sulfides with alkyl hydroperoxides. Several bis(oxazoline)-VO complexes have been prepared and supported by cation exchange in Laponite clay. The substituent in the oxazoline ring, and the type of hydroperoxide are relevant parameters that control the activity and selectivity of the resulting catalysts. Tert-butyl hydroperoxide is more reactive but less enantioselective than cumenehydroperoxide, both with the neat and supported VO-bis(oxazoline) complexes. Activities and enantioselectivities obtained with the heterogeneous catalysts are always lower than in solution, and in general better and more consistent results are obtained with box(Pr) ligand which seems to be also the best chiral auxiliary in homogeneous phase, leading to a modest but significant enantioselectivity of 20% ee in heterogeneous phase and of 28% in homogeneous phase. The recovered of the best catalyst shows a decrease in the catalytic activity and in the enantioselectivity, in agreement with some decomplexation of the chiral ligand, whereas the supported vanadium species remain stable and recoverable.

Financial support from the Spanish Ministerio de Economía y Competitividad (Project CTQ2014-52367-R) and the Diputación General de Aragón (E11 Group co-financed by the European Regional Development Funds) is gratefully acknowledged. M. F. thanks theTunisien Ministère de l’Enseignement Supérieure et la Recherche Scientifique for a short-mobility grant (bourse d'alternance).

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