Low-Valent Molybdenum-Based Dual Pre-Catalysts for Highly Efficient Catalytic Epoxidation of Alkenes and Deoxygenation of Sulfoxides

Authors

  • Sebastian Krackl,

    1. Institute of Chemistry: Metalorganics and Inorganic Materials, Sekr. C2, Technische Universität Berlin, Strasse des 17. Juni 135, D-10623 Berlin (Germany), Fax: (030) 314-29732
    Search for more papers by this author
  • Dr. Anna Company,

    1. Institute of Chemistry: Metalorganics and Inorganic Materials, Sekr. C2, Technische Universität Berlin, Strasse des 17. Juni 135, D-10623 Berlin (Germany), Fax: (030) 314-29732
    Search for more papers by this author
  • Dr. Stephan Enthaler,

    Corresponding author
    1. Institute of Chemistry: Metalorganics and Inorganic Materials, Sekr. C2, Technische Universität Berlin, Strasse des 17. Juni 135, D-10623 Berlin (Germany), Fax: (030) 314-29732
    • Institute of Chemistry: Metalorganics and Inorganic Materials, Sekr. C2, Technische Universität Berlin, Strasse des 17. Juni 135, D-10623 Berlin (Germany), Fax: (030) 314-29732
    Search for more papers by this author
  • Prof. Dr. Matthias Driess

    Corresponding author
    1. Institute of Chemistry: Metalorganics and Inorganic Materials, Sekr. C2, Technische Universität Berlin, Strasse des 17. Juni 135, D-10623 Berlin (Germany), Fax: (030) 314-29732
    • Institute of Chemistry: Metalorganics and Inorganic Materials, Sekr. C2, Technische Universität Berlin, Strasse des 17. Juni 135, D-10623 Berlin (Germany), Fax: (030) 314-29732
    Search for more papers by this author

Abstract

A variety of homoleptic and heteroleptic, triply bonded dimolybdenum hexaalkoxides, [(Mo2(OR)6] and [Mo2(OR)4(OR′)2], were successfully applied as dual pre-catalysts in both, the epoxidation of olefins with tert-butyl hydroperoxide and the deoxygenation of diorganosulfoxides with silanes, to form the corresponding sulfides. In the epoxidation of cyclooctene, the pre-catalysts demonstrated an intriguingly high activity, with turnover frequencies (TOFs) of above 60 000 h−1 at elevated temperatures (≈50 °C) and even very high activity at room temperature. Furthermore, using [Mo2(OtBu)6] as a pre-catalyst, we studied the effect of the solvent and we extended the epoxidation reaction to more demanding olefins, which revealed a particularly high activity even towards primary alkenes. In addition, the same pre-catalysts, in comparison to previously reported Mo-based systems, exhibited excellent activities for the deoxygenation of phenyl methyl sulfoxide to thioanisole in the presence of silanes (TOFs>160 h−1). A number of other diorganosulfoxides were used in the catalytic deoxygenation to investigate the scope and limitations of the system, displaying an excellent performance for differently substituted substrates.

Ancillary