The Swern oxidation, shown in Fig. P10.61, is a very mild two-step procedure for the oxidation of primary and secondary alcohols.

(a) How many electrons are involved in this oxidation? Explain.

(b) What is the oxidizing agent?

(c) The following intermediate A is formed prior to the addition of the base triethylamine.

Triethylamine reacts with intermediate A to give the product aldehyde and the by-product dimethyl sulfide. When an isotopically substituted alcohol RCD₂OH is subjected to the Swern oxidation, a deuteriumsubstituted aldehyde R—CD = O is formed, and the by-product dimethyl sulfide contains one atom of deuterium per molecule, H₃C—S—CH₂D. Write a curved-arrow mechanism for the reaction of intermediate A and the base triethylamine that accounts for the isotopic distribution in the products.

Transcribed Image Text:

+ RCH₂-O-S(CH3)2 CI A