Berti olefination

What is Berti olefination?

Berti first reported on a reaction in 1954 that is used to prepare olefins through the pyrolysis of methyl sulfites of aliphatic or alicyclic alcohols. This reaction is similar to the Chugaev reaction, which involves the pyrolysis of xanthates of alcohols, but differs in that it occurs via a trans pyrolytic elimination mechanism.

Berti olefination
Berti olefination

In contrast to the pyrolysis of other esters of alcohol, which typically proceed via a quasi six-membered ring transition state, the Berti olefination is known to undergo a nonconcerted mechanism involving the heterolysis of the carbon-oxygen bond. This results in ion pairs that subsequently undergo direct proton loss or a 1,2-hydride shift, followed by proton loss from the resulting cationic species.

Notable examples of this reaction include the pyrolysis of cis-2-phenylcyclohexyl methyl sulfite, which yields 1-phenylcyclohexene (78%) in preference to 3-phenylcyclohexene (22%). Additionally, the pyrolysis of 1,2-cis-cyclohexyl diol sulfite produces cyclohexanone, while the pyrolysis of 1,2-trans-cyclohexyl diol sulfite yields cyclopentaldehyde.

References

  • Price, C. C. and Berti, G., J. Am. Chem. Soc., 1954, 76, 1207
  • Price, C. C. and Berti, G., J. Am. Chem. Soc., 1954, 76, 1211
  • Berti G., J. Am. Chem. Soc., 1954, 76, 1213
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