The reason behind rate of bimolecular elimination in 1 , 2 , 3 , 4 , 5 , 6 -hexachlorocyclohexane 7000 times slower than it’s any other stereoisomers should be explained. Concept introduction: Experimental evidence for E2 mechanism pathway suggests that it readily occurs if the leaving group with respect to the proton is in anti- orientation in stable chair conformation. For instance, when cis-1-bromo-4- ( 1,1-dimethylethyl ) cyclohexane is treated with strong base it leads to faster bimolecular elimination to afford the corresponding alkene relative to trans-1-bromo-4- ( 1,1-dimethylethyl ) cyclohexane . This is because in the transition state for E2 elimination as illustrated below:

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Chapter 7.7, Problem 7.15TIY

(a)

Interpretation Introduction

Interpretation: The reason behind rate of bimolecular elimination in 1,2,3,4,5,6-hexachlorocyclohexane 7000 times slower than it’s any other stereoisomers should be explained.

Concept introduction: Experimental evidence for E2 mechanism pathway suggests that it readily occurs if the leaving group with respect to the proton is in anti- orientation in stable chair conformation. For instance, when cis-1-bromo-4-(1,1-dimethylethyl)cyclohexane is treated with strong base it leads to faster bimolecular elimination to afford the corresponding alkene relative to trans-1-bromo-4-(1,1-dimethylethyl)cyclohexane . This is because in the transition state for E2 elimination as illustrated below:

(b)

Interpretation Introduction

Interpretation: The formation of only specific elimination product should be explained.

Concept introduction: Experimental evidence for E2 mechanism pathway suggests that it readily occurs if the leaving group with respect to the proton is in anti- orientation in stable chair conformation. For instance, when cis-1-bromo-4-(1,1-dimethylethyl)cyclohexane is treated with strong base it leads to faster bimolecular elimination to afford the corresponding alkene relative to trans-1-bromo-4-(1,1-dimethylethyl)cyclohexane . This is because in the transition state for E2 elimination as illustrated below:

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