Chiral molybdenum(VI) complexes with tridentate Schiff bases derived from S(+)-1-amino-2-propanol: Synthesis, characterization and catalytic activity in the oxidation of prochiral sulfides and olefins

Seven chiral dioxidomolybdenum(VI) complexes with tridentate Schiff bases were synthesized by mono condensation of S(+)-1-amino-2-propanol with salicylaldehyde and its derivatives. One- (H-1, C-13) and two-dimensional (COSY, gHSQC and NOESY) NMR, IR, CD and UV-Vis spectroscopy were used for detailed characterization of the new molybdenum(VI) compounds. After optimization of the reaction conditions, the catalytic activities of these complexes were tested for the oxidation of olefins, i.e. styrene and cyclohexene, with aqueous 30% H2O2 or tert-butyl hydroperoxide (TBHP) as an oxidant. Moreover, the molybdenum(VI) Schiff base complexes were also able to catalyze the oxidation of prochiral sulfides [PhSR (R = Me, Bz)] to optically active sulfoxides in the presence of aqueous 30% H2O2. (C) 2016 Elsevier Ltd. All rights reserved.