title: Intramolecular [2 + 2] and [4 + 2] Cycloaddition Reactions of Cinnamylamides of Ethenetricarboxylate in Sequential Processes.
abstract: Intramolecular [2 + 2] and [4 + 2] cycloaddition reactions of cinnamylamides of ethenetricarboxylate in sequential processes have been studied. Reaction of 1,1-diethyl 2-hydrogen ethenetricarboxylate and trans-cinnamylamines in the presence of EDCI/HOBt/Et3N led to pyrrolidine products in one pot, via intramolecular [2 + 2], [4 + 2], and some other cyclizations. The types of the products depend on the substituents on the benzene ring and the reaction conditions. Reaction of cinnamylamines without substituents on the benzene ring and with halogens and OMe on the para position at room temperature gave cyclobutane-fused pyrrolidines as major products via [2 + 2] cycloaddition. The reaction at 80 °C in 1,2-dichloroethane gave δ-lactone fused pyrrolidines as major products, probably via ring-opening of the cyclobutanes. Interestingly, reaction of 1,1-diethyl 2-hydrogen ethenetricarboxylate and cinnamylamines bearing electron-withdrawing groups such as NO2, CN, CO2Me, CO2Et, and CF3on ortho and para positions in the presence of EDCI/HOBt/Et3N at room temperature or at 60-80 °C gave tetrahydrobenz[f]isoindolines via [4 + 2] cycloaddition as major products. DFT studies have been performed to explained the observed [2 + 2]/[4 + 2] selectivity.
authors.affiliation: Department of Chemistry, Nara University of Education , Takabatake-cho, Nara 630-8528, Japan.
authors.forename: Shoko
authors.initials: S
authors.lastname: Yamazaki
authors.affiliation: Department of Chemistry, Nara University of Education , Takabatake-cho, Nara 630-8528, Japan.|Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University , Gakuen-cho 1-1, Nakaku, Sakai, Osaka 599-8531, Japan.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Sugiura
authors.affiliation: Department of Chemistry, Nara University of Education , Takabatake-cho, Nara 630-8528, Japan.
authors.forename: Shinnosuke
authors.initials: S
authors.lastname: Ohashi
authors.affiliation: Department of Chemistry, Nara University of Education , Takabatake-cho, Nara 630-8528, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Ishizuka
authors.affiliation: Department of Chemistry, Nara University of Education , Takabatake-cho, Nara 630-8528, Japan.
authors.forename: Rina
authors.initials: R
authors.lastname: Saimu
authors.affiliation: KYOUSEI Science Center, Nara Women's University , Nara 630-8506, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Mikata
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University , Gakuen-cho 1-1, Nakaku, Sakai, Osaka 599-8531, Japan.
authors.forename: Akiya
authors.initials: A
authors.lastname: Ogawa