title: Computational studies on the electrocyclizations of 1-amino-1,3,5-hexatrienes.
abstract: Electrocyclizations of 1,3,5-hexatrienes containing up to four electron-donating and/or electron withdrawing substituents have been studied computationally using the hybrid density functional, B3LYP. Electron donating substituents at positions C-1 and C-5 decrease activation barriers by 0.3 to 2.3 kcal/mol. Introducing of an electron-withdrawing group, CO(2)Me, at C-4 further decreases the activation energy by 7 kcal/mol. Electron-withdrawing groups (NO(2), SO(2)Ph and C=N(+)Me(2)) at C-2 have a profound effect of 17-25 kcal/mol on the activation energy.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, 405 Hilgard Avenue, Los Angeles, California 90095-1569, USA.
authors.forename: Vildan Adar
authors.initials: VA
authors.lastname: Guner
authors.forename: K N
authors.initials: KN
authors.lastname: Houk
authors.forename: Ian W
authors.initials: IW
authors.lastname: Davies