Daily answer writing · Tue, 3 Nov, 2026
E2 needs anti-periplanar H and Cl: menthyl vs neomenthyl chloride
With sodium ethoxide in ethanol, neomenthyl chloride undergoes E2 elimination about 200 times faster than menthyl chloride and gives mainly 3-menthene (the Saytzeff product), whereas menthyl chloride gives only 2-menthene. Explain both the difference in rate and the difference in products using the stereoelectronic requirement of the E2 reaction and the chair conformations of the two chlorides.
Syllabus: Common to CSE Paper II, IFoS Paper II and Geo-Scientist Mains Paper III (organic): E1 and E2 mechanisms, Saytzeff and Hofmann orientation, stereochemistry of elimination, conformations of cyclohexane.
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