title: Mono-, Di-, and Trifluoroalkyl Substituent Effects on the Torquoselectivities of Cyclobutene and Oxetene Electrocyclic Ring Openings.
abstract: 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 σ(CO) bond and the σ(CF)* orbital (σ(CO) → σ(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 σ(CO) bond and trifluoromethyl substituent orbitals compete with the σ(CO) → σ(CF)* interaction.
authors: Department of Applied Chemistry, Tokyo Institute of Technology , Tokyo 152-8552, Japan.
authors: Kazuya
authors: K
authors: Honda
authors: Department of Chemistry & Biochemistry, University of California , Los Angeles, California 90095-1569, United States.
authors: Steven A
authors: SA
authors: Lopez
authors: Department of Chemistry & Biochemistry, University of California , Los Angeles, California 90095-1569, United States.
authors: K N
authors: KN
authors: Houk
authors: Department of Applied Chemistry, Tokyo Institute of Technology , Tokyo 152-8552, Japan.
authors: Koichi
authors: K
authors: Mikami