Mozingo reduction

The Mozingo reduction, also known as Mozingo reaction or thioketal reduction, is a chemical reaction capable of fully reducing a ketone or aldehyde to the corresponding alkane via a dithioacetal.^[1][2] The reaction scheme is as follows:^[3]

Mozingo reduction
Named after	Ralph Mozingo
Reaction type	Organic redox reaction

The ketone or aldehyde is activated by conversion to cyclic dithioacetal by reaction with a dithiol (nucleophilic substitution) in presence of a H⁺ donating acid. The cyclic dithioacetal structure is then hydrogenolyzed using Raney nickel. Raney nickel is converted irreversibly to nickel sulfide. This method is milder than either the Clemmensen or Wolff-Kishner reductions, which employ strongly acidic or basic conditions, respectively, that might interfere with other functional groups.^[4]

History

The reaction is named after Ralph Mozingo, who reported the cleavage of thioethers with Raney nickel in 1942.^[5] However the modern iteration of the reaction, involving the cyclic dithioacetal, was developed by Melville Wolfrom.^[6]

References

1. Francis A. Carey; Richard J. Sundberg (2007). Advanced Organic Chemistry: Reactions and synthesis. Springer. pp. 452–454. ISBN 9780387683508.
2. Mosettig, Erich; Mozingo, Ralph (15 March 2011). "The Rosenmund Reduction of Acid Chlorides to Aldehydes". Organic Reactions: 362–377. doi:10.1002/0471264180.or004.07. ISBN 978-0471264187.
3. Jonathan Clayden; Nick Greeves; Stuart Warren (2012). Organic Chemistry (2 ed.). Oxford University Press. ISBN 9780199270293.
4. Mitchell, Reginald; Lai, Yee-Hing (1980). "The neutral deoxygenation (reduction) of aryl carbonyl compounds with raney-nickel. an alternative to the clemmenson, wolf-kishner or mozingo (thioketal) reductions". Tetrahedron Letters. 21 (27). Elsevier: 2637–2638. doi:10.1016/S0040-4039(00)92825-9.
5. du Vigneaud, Vincent; Melville, Donald B.; Folkers, Karl; Wolf, Donald E.; Mozingo, Ralph; Keresztesy, John C.; Harris, Stanton A. (December 1942). "The Structure of Biotin: A Study of Desthiobiotin". Journal of Biological Chemistry. 146 (2): 475–485. doi:10.1016/S0021-9258(18)44968-X.
6. Wolfrom, M. L.; Karabinos, J. V. (June 1944). "Carbonyl Reduction by Thioacetal Hydrogenolysis". Journal of the American Chemical Society. 66 (6): 909–911. doi:10.1021/ja01234a021.