Posts Tagged ‘Birch reduction’

A new way of exploring the directing influence of (electron donating) substituents on benzene.

Friday, April 17th, 2015
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The knowledge that substituents on a benzene ring direct an electrophile engaged in a ring substitution reaction according to whether they withdraw or donate electrons is very old.[1] Introductory organic chemistry tells us that electron donating substituents promote the ortho and para positions over the meta. Here I try to recover some of this information by searching crystal structures.

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References

  1. H.E. Armstrong, "XXVIII.?An explanation of the laws which govern substitution in the case of benzenoid compounds", Journal of the Chemical Society, Transactions, vol. 51, pp. 258, 1887. http://dx.doi.org/10.1039/CT8875100258

The mechanism of the Birch reduction. Part 3: reduction of benzene

Tuesday, December 4th, 2012
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Birch reduction of benzene itself results in 1,4-cyclohexadiene rather than the more stable (conjugated) 1,3-cyclohexadiene. Why is this?

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The mechanism of the Birch reduction. Part 2: a transition state model.

Monday, December 3rd, 2012
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I promised that the follow-up to on the topic of Birch reduction would focus on the proton transfer reaction between the radical anion of anisole and a proton source, as part of analysing whether the mechanistic pathway proceeds O or M.

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