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Bouveault–Blanc reduction

April 13, 2024

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 first reported by Louis Bouveault and Gustave Louis Blanc in 1903.[2][3][4] Bouveault and Blanc demonstrated the reduction of ethyl oleate and n-butyl oleate to oleyl alcohol.[5] Modified versions of which were subsequently refined and published in Organic Syntheses.[6][7][8]

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

This reaction is used commercially although for laboratory scale reactions it was made obsolete by the introduction of lithium aluminium hydride.[1]

Reaction mechanism edit

Sodium metal is a one-electron reducing agent. Four equivalents of sodium are required to fully reduce each ester. Ethanol serves as a proton source.[1] The reaction produces sodium alkoxides, according to the following stoichiometry:

RCOOR'   +   6 Na   +   4 CH
3CH
2OH   →   RCH
2ONa   +   R'ONa   +   4 CH
3CH
2ONa

In practice, considerable sodium is consumed by the formation of hydrogen. For this reason, an excess of sodium is often required. Because the hydrolysis of sodium is rapid, not to mention dangerous, the Bouveault-Blanc reaction requires anhydrous ethanol.[9][8] The mechanism of the reaction follows:[1]

 

Consistent with this mechanism, sodium-ethanol mixtures will also reduce ketones to alcohols.[10]

This approach to reducing esters was widely used prior to the availability of hydride reducing agents such as lithium aluminium hydride and related reagents. It requires vigorous reaction conditions and has a significant risk of fires, explaining its relative unpopularity. One modification involves encapsulating the alkali metal into a silica gel, which has a safety and yield profile similar to that of hydride reagents.[11] Another modification uses a sodium dispersion.[12][13]

See also edit

References edit

  1. ^ a b c d 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.
  7. ^ Adkins, Homer; Gillespie, R. H. (1949). "Oleyl alcohol". Organic Syntheses. 29: 80. doi:10.15227/orgsyn.029.0080.
  8. ^ a b Ford, S. G.; Marvel, C. S. (1930). "Lauryl Alcohol". Organic Syntheses. 10: 62. doi:10.15227/orgsyn.010.0062.
  9. ^ R. H. Manske (1934). "Decamethylene Glycol". Organic Syntheses. 14: 20. doi:10.15227/orgsyn.014.0020.
  10. ^ Whitmore, Frank C.; Otterbacher, T. (1930). "2-Heptanol". Organic Syntheses. 10: 60. doi:10.15227/orgsyn.010.0060.
  11. ^ Bodnar, Brian S.; Vogt, Paul F. (2009). "An Improved Bouveault-Blanc Ester Reduction with Stabilized Alkali Metals". J. Org. Chem. 74 (6): 2598–2600. doi:10.1021/jo802778z. PMID 19219971.
  12. ^ 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. PMID 24941291.
  13. ^ 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. PMID 28029787.

External links edit

  • Animation of the Bouveault–Blanc reduction

April 13, 2024
bouveault, blanc, reduction, chemical, reaction, which, ester, reduced, primary, alcohols, using, absolute, ethanol, sodium, metal, first, reported, louis, bouveault, gustave, louis, blanc, 1903, bouveault, blanc, demonstrated, reduction, ethyl, oleate, butyl,. 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 first reported by Louis Bouveault and Gustave Louis Blanc in 1903 2 3 4 Bouveault and Blanc demonstrated the reduction of ethyl oleate and n butyl oleate to oleyl alcohol 5 Modified versions of which were subsequently refined and published in Organic Syntheses 6 7 8 Bouveault Blanc reductionNamed after Louis Bouveault Gustave Louis BlancReaction type Organic redox reactionIdentifiersOrganic Chemistry Portal bouveault blanc reductionRSC ontology ID RXNO 0000119 This reaction is used commercially although for laboratory scale reactions it was made obsolete by the introduction of lithium aluminium hydride 1 Contents 1 Reaction mechanism 2 See also 3 References 4 External linksReaction mechanism editSodium metal is a one electron reducing agent Four equivalents of sodium are required to fully reduce each ester Ethanol serves as a proton source 1 The reaction produces sodium alkoxides according to the following stoichiometry RCOOR 6 Na 4 CH3 CH2 OH RCH2 ONa R ONa 4 CH3 CH2 ONaIn practice considerable sodium is consumed by the formation of hydrogen For this reason an excess of sodium is often required Because the hydrolysis of sodium is rapid not to mention dangerous the Bouveault Blanc reaction requires anhydrous ethanol 9 8 The mechanism of the reaction follows 1 nbsp Consistent with this mechanism sodium ethanol mixtures will also reduce ketones to alcohols 10 This approach to reducing esters was widely used prior to the availability of hydride reducing agents such as lithium aluminium hydride and related reagents It requires vigorous reaction conditions and has a significant risk of fires explaining its relative unpopularity One modification involves encapsulating the alkali metal into a silica gel which has a safety and yield profile similar to that of hydride reagents 11 Another modification uses a sodium dispersion 12 13 See also editAcyloin condensation The reductive coupling of esters using sodium to yield an a hydroxyketone Akabori amino acid reaction The reduction of amino acid esters by sodium to yield aldehydes Birch reduction For the reduction of alkenes using sodium Bouveault aldehyde synthesis Another organometallic reaction by Bouveault where a Grignard reagent is converted to an aldehydeReferences edit a b c d 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 Bouveault L Blanc G 1903 Preparation 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 Bouveault L Blanc G 1903 Preparation 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 Bouveault L Blanc G 1904 Transformation des acides monobasiques satures dans les alcools primaires correspondants Transforming saturated monobasic acids into the corresponding primary alcohols Bull Soc Chim Fr in French 31 666 672 Bouveault L Blanc G 1904 Hydrogenation des ethers des acides possedant en outre les fonctions ether oxyde ou acetal 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 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 Adkins Homer Gillespie R H 1949 Oleyl alcohol Organic Syntheses 29 80 doi 10 15227 orgsyn 029 0080 a b Ford S G Marvel C S 1930 Lauryl Alcohol Organic Syntheses 10 62 doi 10 15227 orgsyn 010 0062 R H Manske 1934 Decamethylene Glycol Organic Syntheses 14 20 doi 10 15227 orgsyn 014 0020 Whitmore Frank C Otterbacher T 1930 2 Heptanol Organic Syntheses 10 60 doi 10 15227 orgsyn 010 0060 Bodnar Brian S Vogt Paul F 2009 An Improved Bouveault Blanc Ester Reduction with Stabilized Alkali Metals J Org Chem 74 6 2598 2600 doi 10 1021 jo802778z PMID 19219971 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 PMID 24941291 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 a a Dideuterio Alcohols J Org Chem 82 2 1285 1290 doi 10 1021 acs joc 6b02950 PMID 28029787 External links editAnimation of the Bouveault Blanc reduction Retrieved from https en wikipedia org w index php title Bouveault Blanc reduction amp oldid 1184606941, wikipedia, wiki, book, books, library,

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