One-Pot Reduction of Sulfoxides with NaBH₄, CoCl₂ · 6H₂O Catalyst, and Moist Alumina

Abstract

Sulfoxides are reduced by a combination of sodium borohydride, a catalytic amount of cobalt(II) chloride hexahydrate, and chromatographic neutral alumina preloaded with a small amount of water (moist alumina) in hexane to produce the corresponding sulfides in good to excellent yields under mild conditions. An interesting structural influence of sulfoxides on their reactivity is observed.

Keywords:

• Cobalt(II) chloride hexahydrate
• moist alumina
• reduction
• sodium borohydride
• sulfoxide

ACKNOWLEDGMENTS

The authors thank Dr. Akira Yoshida (Tokyo City University, Instrumental Analysis Center) for his help in carrying out the SEM experiment. The authors also thank Tae Tokuhata for helpful discussions.

Notes

^a At 30 °C, for 3 h; 1 mmol of methyl phenyl sulfoxide, 1 g of moist support (H₂O content, 19 wt%), 0.1 mmol of metal salt, and 10 ml of hexane were used.

^a For 3 h; sulfoxide 1 mmol and hexane 10 ml were used.

^b Moist alumina (H₂O content, 19 wt%).