Pinner reaction

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Pinner reaction
Named after Adolf Pinner
Reaction type Coupling reaction
Identifiers
Organic Chemistry Portal pinner-reaction
RSC ontology ID RXNO:0000361

The Pinner reaction refers to the acid catalysed reaction of a nitrile with an alcohol to form an imino ester salt (alkyl imidate salt); this is sometimes referred to as a Pinner salt.[1] The reaction is named after Adolf Pinner, who first described it in 1877.[2][3][4] Pinner salts are themselves reactive and undergo additional nucleophilic additions to give various useful products:[5]

[6]

Reaction-pinner2.png

Commonly the Pinner salt itself is not isolated, with the reaction being continued to give the desired functional group (orthoester etc.) in one go. It should be appreciated that the Pinner reaction refers specifically to an acid catalyzed process, but that similar results can often be achieved using base catalysis. The two approaches can be complementary, with nitriles which are unreactive under acid conditions often giving better results in the presence of base, and vice versa.[7] The determining factor is typically how electron-rich or poor the nitrile is. For example: an electron-poor nitrile is a good electrophile (readily susceptible to attack from alkoxides etc.) but a poor nucleophile would be difficult to protonate and hence would be expected to react more readily under basic rather than acidic conditions.

See also[edit]

References[edit]

  1. ^ "Pinner Reaction". Comprehensive Organic Name Reactions and Reagents (504): 2237–2240. 2010. doi:10.1002/9780470638859.conrr504.
  2. ^ A. Pinner, F. Klein; Klein (1877). "Umwandlung der Nitrile in Imide". Berichte der deutschen chemischen Gesellschaft. 10 (2): 1889–1897. doi:10.1002/cber.187701002154.
  3. ^ A. Pinner, Fr. Klein; Klein (1878). "Umwandlung der Nitrile in Imide". Berichte der deutschen chemischen Gesellschaft. 11 (2): 1475–1487. doi:10.1002/cber.18780110258.
  4. ^ A. Pinner (1883). "Ueber die Umwandlung der Nitrile in Imide". Berichte der deutschen chemischen Gesellschaft. 16 (2): 1643–1655. doi:10.1002/cber.18830160235.
  5. ^ Roger, R.; Neilson, D. G. (1961). "The Chemistry of Imidates". Chem. Rev. 61 (2): 179–211. doi:10.1021/cr60210a003.
  6. ^ Adams, Roger; Thal, A. F. (1922). "Ethyl Phenylacetate". Organic Syntheses. 2: 27. doi:10.15227/orgsyn.002.0027.
  7. ^ Schaefer, F. C.; Peters, G. A. (1961). "Base-Catalyzed Reaction of Nitriles with Alcohols. A Convenient Route to Imidates and Amidine Salts". Journal of Organic Chemistry. 26 (2): 412. doi:10.1021/jo01061a034.