Wittig Reaction

Definition:

Alkene formation from carbonyl compounds and phosphonium ylides

Frequency of appearance:

        This bar graph represents all of the online articles that were found to contain this specific name reaction in the title of the article. Tetrahedron letters, Tetrahedron, Synthetic letters, Synthesis, Journal of Organic Chemistry and Journal of the American Chemical Society are represented here. This table by no means represents the periodicity of the name reaction found in the literature.

Original References:

1. Wittig, G.; Rieber, M. Ann., 1949, 562, 187.
2. Wittig, G.; Schöllkopf, U. Chem. Ber., 1954, 87, 1318.

Recent academic references: Click here for more references

3. First Isolation and Characterization of an Anti-Apicophilic Spirophosphorane Bearing an Oxaphosphetane Ring: A Model for the Possible Reactive Intermediate in the Wittig Reaction

• Kojima, S.; Sugino, M.; Matsukawa, S.; Nakamoto, M.; Akiba, K.-y.;
  J. Am. Chem. Soc.; 2002; 124(26); 7674-7675.  

4. Improved E-selectivity in the Wittig reaction of stabilized ylides with alpha-alkoxyaldehydes and sugar lactols

• Harcken, C.; Martin, S. F.; Org. Lett.; 3(22); 3591-3593 (2001).

5. A Novel Synthesis of 4H-Chromen-4-ones via Intramolecular Wittig Reaction

• Kumar, P.; Bodas, M. S.; Org. Lett., 2(24); 3821-3823 (2000).

6. http://www.uni-leipzig.de/~nmr/STB/wittig4.pdf

Recent process references:

7. Process Research on the Synthesis of Silthiofam: A Novel Fungicide for Wheat

• Phillips, G. W.; Fevig, T. L.; Lau, P. H.; Klemm, G. H.; Mao, M. K.; Ma, C.; Gloeckner, J. A.; Clark, A. S.; Org. Process Res. Dev.; 2002; 6(4); 357-366.  

Mechanism: http://library.tedankara.k12.tr/chemistry/vol5/Breaking and connecting carbon chains/o70.htm

Scope and Limitations:

• Phosphorous ylide reactivity depends on substituent: electron withdrawing groups decrease reactivity. ^B
• Ylides are sensitive to oxygen, water and alcohols. ^{A+ B}
• Aldehydes or ketones may be aliphatic, aromatic or alicyclic. ^A
• Reactivity of the carbonyl compound increases with increased electrophillic character. ^B
• Lactones may be effected by this reaction. ^A
• Generally E stereoselectivity is observed when the ylide contains a stabilizing group. ^A
• E selectivity increased by: increased temperature, nonpolar solvents, carboxylic acd (catalytic)^{. 4}
• Z selectivity increased by: protic solvents, using tributylphosphoranes (instead of aryl). ⁴
• THF is commonly used as a solvent.

Synonyms: