Bouveault–Blanc reduction

Bouveault-Blanc reduction
Named after Louis Bouveault
Gustave Louis Blanc
Reaction type Organic redox reaction
Identifiers
Organic Chemistry Portal bouveault-blanc-reduction
RSC ontology ID RXNO:0000119

The Bouveault–Blanc reduction is a chemical reaction in which an ester is reduced to primary alcohols using absolute ethanol and sodium metal.[1] It was developed by Louis Bouveault and Gustave Louis Blanc and first reported in 1903.[2][3][4] Bouveault and Blanc demonstrated the reduction of ethyl oleate and n-butyl oleate to oleyl alcohol and ethanol or 1-butanol,[5] modified versions of which were subsequently refined and published in Organic Syntheses.[6][7]

This reaction is used as an industrial alternative to lithium aluminium hydride reduction.[1]

Reaction mechanism

Sodium metal is a single-electron reducing agent, which means the sodium metal will transfer electrons one at a time. Four sodium atoms are required to fully reduce each ester to alcohols, using ethanol as a proton source,[1] according to the following stoichiometry:

R
1COOR
2   +   4 Na   +   4 CH
3CH
2OH   →   R
1CH
2OH   +   R
2OH   +   4 CH
3CH
2ONa

The mechanism of the reaction is as follows:[1]

This approach to reducing esters was widely used prior to the availability of hydride reducing agents such as lithium aluminium hydride and sodium borohydride. It requires vigorous reaction conditions and has a significant risk of fires, explaining its relative unpopularity. A modification reported in 2009 involving encapsulating the alkali metal into a silica gel, which has a safety and yield profile similar to that of hydride reagents.[8] Another modification using a sodium dispersion has also been explored.[9][10]

See also

References

  1. 1 2 3 4 Wang, Zerong, ed. (2009). "109. Bouveault–Blanc Reduction". Comprehensive Organic Name Reactions and Reagents. pp. 493–496. doi:10.1002/9780470638859.conrr109. ISBN 978-0-471-70450-8.
  2. ↑ Bouveault, L.; Blanc, G. (1903). "Préparation des alcools primaires au moyen des acides correspondants" [Preparation of primary alcohols by means of the corresponding acids]. Compt. Rend. (in French). 136: 1676–1678.
  3. ↑ Bouveault, L.; Blanc, G. (1903). "Préparation des alcools primaires au moyen des acides correspondants" [Preparation of primary alcohols by means of the corresponding acids]. Compt. Rend. (in French). 137: 60–62.
  4. ↑ Bouveault, L.; Blanc, G. (1904). "Transformation des acides monobasiques saturés dans les alcools primaires correspondants" [Transforming saturated monobasic acids into the corresponding primary alcohols]. Bull. Soc. Chim. Fr. (in French). 31: 666–672.
  5. ↑ Bouveault, L.; Blanc, G. (1904). "Hydrogénation des éthers des acides possédant en outre les fonctions éther-oxyde ou acétal" [Hydrogenation of the ether of the acids furthermore possessing the ether-oxide or acetal functions]. Bull. Soc. Chim. Fr. (in French). 31 (3): 1210–1213.
  6. ↑ Reid, E. E.; Cockerille, F. O.; Meyer, J. D.; Cox, W. M.; Ruhoff, J. R. (1935). "Oleyl Alcohol". Organic Syntheses. 15: 51. doi:10.15227/orgsyn.015.0051. ; Collective Volume, 2, p. 468
  7. ↑ Adkins, Homer; Gillespie, R. H. (1949). "Oleyl alcohol". Organic Syntheses. 29: 80. doi:10.15227/orgsyn.029.0080. ; Collective Volume, 3, p. 671
  8. ↑ Bodnar, Brian S.; Vogt, Paul F. (2009). "An Improved Bouveault-Blanc Ester Reduction with a second Stabilized Alkali Metals". J. Org. Chem. 74 (6): 2598–2600. doi:10.1021/jo802778z.
  9. ↑ An, Jie; Work, D. Neil; Kenyon, Craig; Procter, David J. (2014). "Evaluating a Sodium Dispersion Reagent for the Bouveault–Blanc Reduction of Esters". J. Org. Chem. 79 (14): 6743–6747. doi:10.1021/jo501093g.
  10. ↑ Han, Minhui; Ma, Xiaodong; Yao, Shangchu; Ding, Yuxuan; Yan, Zihan; Adijiang, Adila; Wu, Yufei; Li, Hengzhao; Zhang, Yuntong; Lei, Peng; Ling, Yun; An, Jie (2017). "Development of a Modified Bouveault–Blanc Reduction for the Selective Synthesis of α,α-Dideuterio Alcohols". J. Org. Chem. 82 (2): 1285–1290. doi:10.1021/acs.joc.6b02950.
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