E2 Regiospecific Elimination from Menthyl Chlorides to Menthenes

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Click the structures and reaction arrows in sequence to view the 3D models and animations respectively

Stereospecific E2 elimination

Stereospecific E2 eliminations - two diastereoisomeric chlorides derived from menthol give two different regioisomers of alkene.
Manipulate the conformations to explore the arrangements of the protons and the chlorine. Are they anti-periplanar as required for E2?

Examine the animated energy plots of Diastereoisomer A and Diastereoisomer B to determine the relative energies of the anti-periplanar conformations required for E2 elimination. Observe the very high energy all-axial conformation and how this is avoided by using a twist-boat conformation in the elimination mechanism.

J. F. Bunnett, Angew. Chemie Int. Ed. English, 1962, 1, 225–235.