An Overview of Mechanism(discussion)
In the course of this organic reaction, protonation of one of the -OH groups occurs and a carbocation is formed. If both the -OH groups are not alike, then the one which yields a more stable carbocation participates in the reaction. Subsequently, an alkyl group from the adjacent carbon migrates to the carbocation center. The driving force for this rearrangement step is believed to be the relative stability of the resultant oxonium ion, which has complete octet configuration at all centers (as opposed to the preceding carbocation). The migration of alkyl groups in this reaction occurs in accordance with their usual migratory aptitude, i.e.Ar>>>> hydride > Ph- > tertiary > secondary > methyl . the conclusion which group stabilises carbo cation more effectively is migrated
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