Corey-Winter olefin synthesis

What is Corey-Winter olefin synthesis?

The Corey-Winter olefin synthesis, discovered in 1963 by Corey and Winter, is a chemical reaction that converts 1,2-diols into alkenes via the elimination of cyclic thionocarbonate. The intermediate cyclic thionocarbonate can be obtained from the reaction of 1,2-diols with either thiophosgene CSCl2 or thiocarbonyldiimidazole, or by treating 1,2-diols with n-butyllithium n-BuLi followed by the addition of carbon disulfide CS2 and methyliodide ICH3. The reaction, also known as Corey-Winter olefination, Corey-Winter olefination reaction, Corey-Winter reaction, Corey-Winter alkene synthesis, Corey-Winter cis-deoxygenation, and Corey olefin synthesis, is performed in the presence of trimethyl- or triethylphosphite.

Corey-Winter olefin synthesis - Corey-Winter olefination - Corey-Winter olefination reaction - Corey-Winter reaction -Corey-Winter alkene synthesis - Corey-Winter cis-deoxygenation - Corey olefin synthesis - cis-olefin from cis-diol and trans-olefin from trans-diol
Corey-Winter olefin synthesis (cis-olefin from cis-diol and trans-olefin from trans-diol)

The resulting olefin is produced via a cis-elimination reaction. A similar method for preparing olefins, known as the Corey-Hopkins methodology or Corey-Hopkins protocol, was reported by Corey and Hopkins in 1982. The reaction can proceed via two mechanisms: either the attack of phosphite on sulfur to form an unstable carbene that reacts with another phosphite to eliminate carbon dioxide and produce the olefin, or a concerted, cyclo-elimination mechanism.

The position-specific and stereospecific nature of the reaction makes it suitable for synthesizing highly substituted or strained olefins. It has also been successfully applied in the preparation of sugar derivatives.

References

A New, Stereospecific Olefin Synthesis from 1,2-Diols
E. J. Corey and Roland A. E. Winter
Journal of the American Chemical Society 1963 85 (17), 2677-2678
DOI: 10.1021/ja00900a043

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