Triethyl amine as an effective reducing agent for sulfoxide deoxygenation.

Enabled by triethyl amine (Et 3 N) and thionyl chloride (SOCl 2 ), an efficient and practical protocol for deoxygenation of sulfoxide to sulfide was developed. This new method features a wide range of substrate scope, including diaryl, dialkyl and aryl alkyl substituted sulfoxides. Detailed mechanistic investigations reveal the crucial role played by Et 3 N as an electron-donating reductant rather than a hydrogen-atom donor.