Barton-Kellogg olefination

What is Barton-Kellogg olefination?

Concurrently in 1970, Barton and Kellogg independently reported a reaction, which is commonly referred to as the Barton-Kellogg olefination, Barton-Kellogg olefin synthesis, or Barton-Kellogg reaction. This reaction involves coupling two ketones to form alkenes and is particularly useful for synthesizing hindered alkenes.

Barton-Kellogg olefination - Barton-Kellogg olefin synthesis - Barton-Kellogg reaction
Barton-Kellogg olefination

The introduction of steric constraints in this reaction occurs through a series of sequential steps, starting with a 1,3-dipolar cycloaddition that forms a five-membered Δ3-1,3,4-thiadiazoline, followed by nitrogen elimination to produce a three-membered episulfide, and finally sulfur extrusion to yield the desired alkenes. Although this reaction can be used to create asymmetric alkenes using two different ketones, the formation of symmetric alkenes is an unavoidable by-product.

The application of this reaction is particularly useful in the synthesis of alkenes, especially those that are highly crowded.

References

  • Barton, D. H. R. and Willis, B. J., J. Chem. Soc., Chem. Commun., 1970, 1226.
  • Barton, D. H. R. and Willis, B. J., J. Chem. Soc., Perkin Trans. I, 1972, 305.
  • Kellogg, R. M. and Wassenaar, S., Tetrahedron Lett., 1970, 1987.
  • Kellogg, R. M.; Wassenaar, S. and Buter, J., Tetrahedron Lett., 1970, 4689.
  • Buter, J.;Wassenaar, S. and Kellogg, R. M., J. Org. Chem., 1972, 37, 4045.
Shares