Mono-, Di-, and Trifluoroalkyl Substituent Effects on the Torquoselectivities of Cyclobutene and Oxetene Electrocyclic Ring Openings

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• 作者：Kazuya Honda ; Steven A. Lopez ; K. N. Houk ; Koichi Mikami
• 刊名：Journal of Organic Chemistry
• 出版年：2015
• 出版时间：December 4, 2015
• 年：2015
• 卷：80
• 期：23
• 页码：11768-11772
• 全文大小：359K
• ISSN：1520-6904

文摘

The reactivities and torquoselectivities of electrocyclic ring opening reactions of fluoromethyl-substituted cyclobutenes and oxetenes were studied with M06-2X density functional theory. The torquoselectivities of a series of mono-, di-, and trifluoromethylcyclobutenes and oxetenes result from the interplay of favorable orbital interactions and closed-shell repulsions. When the substituent rotates inward, there can be a favorable interaction between the breaking 蟽_CO bond and the 蟽_CF* orbital (蟽_CO 鈫?蟽_CF*) of the fluoromethyl group in fluoromethyloxetenes. The preference for rotation of a fluoromethyl group is decreased in trifluoromethyloxetenes because closed-shell repulsions between the breaking 蟽_CO bond and trifluoromethyl substituent orbitals compete with the 蟽_CO 鈫?蟽_CF* interaction.