Related Experiment Video
Updated: Mar 25, 2026

Chemoselective Modification of Viral Surfaces via Bioorthogonal Click Chemistry
Published on: August 19, 2012
Cooperative Reactivity in an Extended-Viologen-Based Cyclophane
Edward J Dale1, Daniel P Ferris1, Nicolaas A Vermeulen1
1Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States.
Abstract:
A tetracationic pyridinium-based cyclophane with a box-like geometry, incorporating two juxtaposed alkyne functions, has been synthesized. The triple bonds are reactive through cycloadditions toward dienes and azides, promoted by the electron-withdrawing nature of the pyridinium rings, as well as by the strain inherent in the cyclophane. The cycloadditions proceeded in high yields, with the cyclophane reacting faster than its acyclic analogue. While the cyclophane contains two reactive triple bonds, there is no evidence for a stable monofunctional intermediate-only starting material and the difunctional product have been detected by (1)H NMR spectroscopy. Molecular modeling of the energy landscape reveals a lower barrier for the kinetically favored second cycloaddition compared with the first one. This situation results in tandem cascading reactions within rigid cyclophanes, where reactions at a first triple bond induce increased reactivity at a distal second alkyne.
More Related Videos
Related Concept Videos
Cycloaddition Reactions: MO Requirements for Photochemical Activation
Cycloaddition Reactions: MO Requirements for Thermal Activation
Cycloaddition Reactions: Overview
Stability of Substituted Cyclohexanes
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation
Lytic Cycle of Bacteriophages

