Takai-Lombardo Reaction

Takai-Lombardo Reaction

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  • Generality
  • Reagent Availability
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  • General Characteristics

In the Takai olefination, carbonyl compounds are olefinated using organotitanium reagents derived from gem-dihaloalkanes.

Whereas most of other olefination reactions are effective only for aldehydes and ketones, the Takai conditions allow for the olefination of esters and amides too. Thanks to the low basicity of the system, enolizable substrates can be olefinated.

Another feature of this reaction is that while similar reagents such as the Tebbe and the Petasis reagents are limited to methylenation, the Takai reagent can be used to synthesize substituted alkenes. The reaction is generally Z-selective.

  • General References

Takai, K.; Hotta, Y.; Ohshima, K.; Nozaki, H. Tetrahedron Lett. 1978, 19, 2417. doi:10.1016/S0040-4039(01)94789-6

Lombardo, L. Tetrahedron Lett.1982, 23, 4293. doi:10.1016/S0040-4039(00)88728-6

Okazoe, T.; Takai, K.; Oshima, K.; Utimoto, K. J. Org. Chem.1987, 52, 4410. DOI: 10.1021/jo00228a055

Lombardo, L. Org. Synth.1987, 65, 81. [PDF]

Takai, K.; Kakiuchi, T.; Kataoka, Y.; Uchimoto, K. J. Org. Chem.1994, 59, 2668. DOI: 10.1021/jo00089a002 

Hartley, R. C.; McKiernan, G. J. JCS Perkin Trans. 12002, 2763. doi: 10.1039/B009709H

  •  Reaction Mechanismtakai_lombardo_2.gif

  • Examples

An example in the context of tetrodotoxin synthesis.[1]


  •  Experimental Procedure

  • Experimental Tips

  • References

[1] Hinman, A.; Du Bois, J. J. Am. Chem. Soc. 2003, 125, 11510. DOI: 10.1021/ja0368305

  • Related Reactions

Takeda Olefination

  • Related Books

  • External Links

Takai-Lombardo Reaktion – Wikipedia(de)

Organotitanium Compound – Wikipedia

Reagents for Alkylidenations (PDF)