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Showing posts with label ALCOHOLS AND ETHERS:. Show all posts
Showing posts with label ALCOHOLS AND ETHERS:. Show all posts

Friday, February 7, 2020

Primary (1°) alcohols are poor starting materials for the synthesis of 1-alkenes. Why ?

Because the 1°carbocation RCH2+ rearranges and a 2-alkene is formed. Even if a 1-alkenes forms it tends to rearrange in acid to a 2-alkene.

Related Questions:

To synthesize 2, 3-dimethylbut-1-ene in the better yield dehydrohalogenation of 2, 3-dimethyl-1-bromobutane is preferred over dehydration of 2, 3-dimethylhutan-1-ol. Why ?


To synthesize 2, 3-dimethylbut-1-ene in the better yield dehydrohalogenation of 2, 3-dimethyl-1-bromobutane is preferred over dehydration of 2, 3-dimethylhutan-1-ol. Why ?

Because dehydration of alcohol is accompanied by a hydride shift leading to an intermediate 3°carbocation which gives 2, 3-dimethylbut-2-ene.      

Related Questions:

Why dehydration proceeds in acid but not in base?

OH- is a very poor leaving group (a strong base) hence it cannot be eliminated under basic conditions. But in the presence of acid -OH is converted to -OH2 a very good leaving group and thus elimination occurs. 

Related Questions:

To synthesize 2, 3-dimethylbut-1-ene in the better yield dehydrohalogenation of 2, 3-dimethyl-1-bromobutane is preferred over dehydration of 2, 3-dimethylhutan-1-ol. Why ?

  

Why alcohols do not undergo base induced dehydration in the same way that alkyl halides are dehydrohalogenated ?

In the dehydration reaction of alcohols the leaving group is -OH- which is a very strong base. Thus reaction cannot proceed in the presence of other base.  

Related Questions:

To synthesize 2, 3-dimethylbut-1-ene in the better yield dehydrohalogenation of 2, 3-dimethyl-1-bromobutane is preferred over dehydration of 2, 3-dimethylhutan-1-ol. Why ?