Related Experiment Video
Updated: Aug 21, 2026

Preparation of a Corannulene-functionalized Hexahelicene by Copper(I)-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units
Published on: September 18, 2016
Computational studies on the electrocyclizations of 1-amino-1,3,5-hexatrienes
Vildan Adar Guner1, K N Houk, Ian W Davies
1Department of Chemistry and Biochemistry, University of California, Los Angeles, 405 Hilgard Avenue, Los Angeles, California 90095-1569, USA.
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.
Related Concept Videos
Thermal and Photochemical Electrocyclic Reactions: Overview
Thermal Electrocyclic Reactions: Stereochemistry
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Photochemical Electrocyclic Reactions: Stereochemistry
Selection Rules: Photochemical Activation
Aromatic Hydrocarbon Cations: Structural Overview
Removing one hydrogen from the intervening CH2 group with both...
Cycloaddition Reactions: Overview
Cycloaddition Reactions: MO Requirements for Photochemical Activation

