Date of Award
Master of Arts
Dr. Don C. Iffland
Dr. Donald C. Berndt
Dr. Robert E. Harmon
Masters Thesis-Open Access
A method of selective oxidation of primary and secondary alcohols to the corresponding aldehydes and ketones has been developed recently, namely the use of dimethyl sulfoxide (DMSO) as the oxidizing agent, either alone or with dicyclohexylcarbodiimide (DCC)14, acid anhydrides1, or alkyl chloroformates10. The negatively polarized oxygen atom of the sulfoxide group in DMSO is ideally situated for a transfer to many electron-deficient substrates. The oxygen of the alcohol coordinates with the sulfur atom of DMSO through its oxygen atom; this is followed by β-elemination of dimethyl sulfide, thereby resulting in oxidation of the alcohol to an aldehyde.
Among the earliest applications of this process have been the oxidation of α-haloketones10, α-haloesters9, alkylhalides11, alkyl tosylates11b,20, and epoxides5. Upon heating the compounds with DMSO in the presence of an acid acceptor such as sodium bicarbonate, a ketone or an aldehyde is formed. With primary iodides and tosylates, oxidation is often quite efficient; but with less reactive compounds, the formation of olefins and other by-products frequently occurs.
The mechanism usually accepted for this reaction involves nucleophilic displacement of a halide or tosylate by the oxygen atom in DMSO to give the intermediate sulfoxonium compound (Ia), which then decomposes into a carbonyl compound by concerted elimination of a proton and dimethyl sulfide9,2.
Zenarosa, Carmen Vargas, "Dimethyl Sulfoxide Oxidation of Primary Alcohols" (1966). Masters Theses. 4374.