what is steric hindrance

Asked by singhdivyanshu633 | 24th Dec, 2015, 08:58: PM

Expert Answer:

Dear Student
 
Steric hindrance: The prevention or retardation of chemical reaction because of neighboring groups on the same molecule; for example, ortho-substituted aromatic acids are more difficult to esterify than are the meta and para substitutions.

If a tertiary halide is used, elimination competes over substituion and an alkene is formed instead of ether. This is because of steric hinderance. We use an alkoxide which has to donate a pair of electrons to the tertiary carbon. Since the tertiary carbon is surrounded by three alkyl groups , it leads to overcrowding around the carbon atom. Hence the alkoxide cannot approach the carbon properly instead approaches the side carbon and forms an alkene.
 
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Answered by Prachi Sawant | 26th Dec, 2015, 11:43: AM

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