Computational Studies on the Electrocyclizations of 1-Amino-1,3,5-hexatrienes
2004-11-12T00:00:00Z (GMT) by
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<sub>2</sub>Me, at C-4 further decreases the activation energy by 7 kcal/mol. Electron-withdrawing groups (NO<sub>2</sub>, SO<sub>2</sub>Ph and CN<sup>+</sup>Me<sub>2</sub>) at C-2 have a profound effect of 17−25 kcal/mol on the activation energy.
CC BY-NC 4.0