Metal-Free Highly Efficient Aerobic Oxidation of Sulfides to Sulfoxides Catalyzed by DBDMH/TBN/H₂O

Abstract

A highly efficient metal-free catalytic system, 1,3-dibromo-5,5-dimethylhydantoin (DBDMH)–tert-butylnitrite (TBN)–H₂O, has been developed for an environmentally friendly and economical aerobic acid-free oxidation of sulfides. TBN was identified as an efficient NO equivalent for the activation of molecular oxygen. Under optimal conditions, a variety of sulfides substrates were converted into their corresponding sulfoxides in good yields by molecular oxygen.

GRAPHICAL ABSTRACT

Keywords:

• Aerobic oxidation
• DBDMH
• molecular oxygen
• sulfides
• sulfoxides
• TBN

ACKNOWLEDGMENT

The research was supported by Program for Changjiang Scholars and Innovative Research Team in University (IRT0711).

Notes

^a Reaction conditions: methyl phenyl sulfide (10 mmol), DBDMH 0.0572g (2 mol%), TBN 0.05 mL (4 mol%), CH₃CN (20 mL), O₂ (0.8 MPa), 50 °C (oil bath temperature), 2 h.

^b Conversions were determined by GC with area normalization.

^c Isolated yield.

^a Reaction conditions: substrates (10 mmol), DBDMH 0.0572 g (2 mol%), TBN 0.05 mL (4 mol%), CH₃CN (20 mL), H₂O (1.5 mL), 50 °C (oil bath temperature).

^b Conversions were determined by GC with area normalization.

^c Isolated yield.