Pericyclic Reactions of Cyclopentadienones with Nonactivated Olefins in Phenolic Solvents. Enhancement of the Reactivity and Periselectivity

详细信息    查看全文

• 作者：Jikyo ; Tamaki ; Eto ; Masashi ; Harano ; Kazunobu
• 刊名：Tetrahedron
• 出版年：1999
• 出版时间：May 7, 1999
• 年：1999
• 卷：55
• 期：1
• 页码：6051-6066
• 全文大小：706 K

文摘

The solvent effect of phenols on the reactivity and periselectivity for the pericyclic reactions of cyclopentadienones with olefins involving conjugated medium-ring polyenes has been investigated. The use of phenols as a solvent accelerates the reaction rates of cycloadditions of cyclopentadienones with nonactivated olefins. In the reaction of cycloheptatriene in p-chlorophenol, the exo [4+6]π cycloadduct was produced predominantly, in which a 15-fold increase of the reaction rate was observed as compared with that in benzene. The [3,3]-sigmatropy and decarbonylation of the primary cycloadducts were also accelerated by phenols. The possible role of phenols is discussed on the basis of kinetic and molecular orbital (MO) calculation data.