Enantioselective Sulfoxidation as a Probe for a Metal-Based Mechanism in H2O2-Dependent Oxidations Catalyzed by a Diiron Complex

• DOI: 10.1021/ic980958j
• Publication Date: 2002-07-26T05:34:27Z
• Authors: Carole Duboc-Toia; Stéphane Ménage; Raymond Y. N. Ho; Lawrence Que,; Claude Lambeaux; Marc Fontecave
• Keywords: Sulfoxide; Thioanisole; Enantiomeric excess; Moiety; Peroxide

The catalytic properties of the diiron complex 1, Fe(2)OL(4)(H(2)O)(2)(ClO(4))(4) with L = (-)-4,5-pinenebipyridine, a chiral bipyridine derivative, have been investigated. Complex 1 efficiently catalyzes oxidation aryl sulfides to corresponding sulfoxides by hydrogen peroxide, yields ranging from 45 90% based on oxidant. Furthermore reactions were enantioselective and produced mixture sulfoxide enantiomers significant enantiomeric excesses. largest ee value (40%) was found in case p-bromophenyl methyl sulfide. Optimal ee's obtained polar solvents at low temperature (below 0 degrees C), when excess oxidant limited. observation (i) saturation kinetics respect both sulfide H(2)O(2) concentrations, (ii) linear Hammett correlation initial V(max) values sigma(p) values, for series p-substituted sulfides, (iii) iron-peroxo complexes, characterized light absorption Raman resonance spectroscopies, during reaction H(2)O(2), (iv) into complexes led us propose that moiety is actual oxygen atom donor substrate, thus explaining control reaction. These data demonstrate oxidations non heme can proceed through metal-based pathways be made stereoselective.