DBDMH/NaNO₂ Catalyst: Transition-Metal-Free Approach to Highly Efficient Aerobic Oxidation of Sulfides to Sulfoxides

Abstract

DBDMH/NaNO₂/O₂ in water is a very efficient nonmetal transition system for catalytic oxidation of a variety of sulfides to the corresponding sulfoxides. The present catalytic system utilizes cheap and readily available agents as the catalysts and has the advantages of simple operations, easy separation of products, and high yields.

Keywords:

• Oxygen
• sulfides
• sulfoxides
• water

Notes

^a Reaction conditions: methyl phenyl sulfide (MPS) (10 mmol), O₂ (1 MPa), 100 °C (oil bath temperature), H₂O (1.5 mL).

^b DBDMH (0.2 mmol, 0.0572 g), NaNO₂ (0.5 mmol, 0.0345 g).

^c Conversions were determined by GC with area normalization.

^d Isolated yields.

^a Reaction conditions: methyl phenyl sulfide (MPS) (10 mmol), DBDMH (0.2 mmol), NaNO₂ (0.5 mmol), O₂ (1 MPa), 100 °C (oil bath temperature), H₂O (1.5 mL).

^b Conversions were determined by GC with area normalization.

^a Reaction conditions: methyl phenyl sulfide (10 mmol), DBDMH (0.2 mmol), NaNO₂ (0.5 mmol), CH₃CN (20 mL), O₂ (1 MPa), 100 °C (oil bath temperature), 3 h.

^b Conversions were determined by GC with area normalization.

^c Isolated yields.

^a Reaction conditions: substrates (10 mmol), DBDMH (0.2 mmol), NaNO₂ (0.5 mmol), H₂O (1.5 mL), CH₃CN (20 mL), O₂ (1 MPa), 100 °C (oil bath temperature), 3 h.

^b Conversions were determined by GC with area normalization.

^c Isolated yields.

^d 4-Methoxyphenyl methyl sulfide and 4-(methylthio)acetophenone were reacted by using 0.4 mmol DBDMH while other conditions were not changed.