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The pinacol–pinacolone rearrangement is a method for converting a 1,2-diol to a carbonyl compound in organic chemistry. The 1,2-rearrangement takes place under acidic conditions. The name of the reaction comes from the rearrangement of pinacol to pinacolone. : This reaction was first described by Wilhelm Rudolph Fittig in 1860AD. The Fittig reaction is named after him. It involves couplng of 2 aryl halides in presence of sodium metal in dry etherial solution. ==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.hydride > Phenyl > tertiary carbocation (if formed by migration) > secondary carbocation (if formed by migration) > methyl cation . The conclusion which group stabilizes carbocation more effectively is migrated 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Pinacol rearrangement」の詳細全文を読む スポンサード リンク
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