NEET Questions Solved

What is major product of following reaction ?

(3) Dehydrohalogenation is an example of anti elimination.



Dehydrohalogenation: A reaction in which a hydrogen atom and a halogen atom are removed from adjacent atoms in a molecule, forming (usually) an alkene or an alkyne.


When reacted with strong base such as hydroxide ioncyclohexyl chloride suffers dehydrohalogenation by a concerted E2 reaction mechanism (shown here). The atoms which comprise the moleculeof HCl lost are shown in red. This reaction is the conceptual reverse of electrophilic addition of HCl to cyclohexene.

tertiary alkyl halide such as 2-iodo-2-methylpropane can undergo dehydrohalogenation by the E1 reaction mechanism (shown here). The atoms which comprise the molecule of HI lost are shown in red.

When reacted with a strong base such as sodium amide (NaNH2), a geminal dibromide can undergo a double dehydrohalogenation reaction to give an alkyne. The reaction involves a pair of consecutive E2 elimination steps.

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