Concept explainers
(a)
Interpretation:
The type of pericyclic reaction required to form benzene from Dewar benzene is to be stated.
Concept introduction:
The isomer of benzene having bicyclic ring with the molecular formula of C6H6 is termed as Dewar benzene or bicyclo [2, 2, 0] hexa-2, 5-diene. This structure is included in the list of possible structure of benzene and named after James Dewar. However, this bicyclic ring structure is not accepted as the true structure of benzene and Dewar supported the Kekule structure of benzene.
(b)
Interpretation:
Dewar benzene, although a very unstable molecule, is not readily transformed to benzene is to be explained.
Concept introduction:
Pericyclic reactions deal with electrons shift in a concerted manner. Moreover, in these reactions the breaking of reactant bonds and the formation of product bonds are formed at the same time. Notably, the pericyclic reactions are classified as electrocyclic, cycloaddition and sigmatropic reactions based on the activation of reaction, the number of electrons involved and the stereochemistry outcome of the reactions.
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EBK ORGANIC CHEMISTRY
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