Related Experiment Video
Updated: Jul 14, 2026

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
Published on: May 26, 2019
Intramolecular ketenimine-ketenimine [2 + 2] and [4 + 2] cycloadditions
Mateo Alajarín1, Baltasar Bonillo, Pilar Sanchez-Andrada
1Departamento de Química Orgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain. alajarin@um.es
Abstract:
Bis(ketenimines), in which the two heterocumulenic functions are placed in close proximity on a carbon skeleton to allow their mutual interaction, show a rich and not easily predictable chemistry. Intramolecular [2 + 2] or [4 + 2] cycloadditions are, respectively, observed when both ketenimine functions are supported on either ortho-benzylic or 2,2'-biphenylenic scaffolds. In addition, nitrogen-to-carbon [1,3] and [1,5] shifts of arylmethyl groups in N-arylmethyl-C,C-diphenyl ketenimines are also disclosed.
More Related Videos
Related Concept Videos
Cycloaddition Reactions: Overview
Cycloaddition Reactions: MO Requirements for Thermal Activation
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
Intramolecular Aldol Reaction
Cycloaddition Reactions: MO Requirements for Photochemical Activation
Conjugate Addition (1,4-Addition) vs Direct Addition (1,2-Addition)
Conjugate addition results in a thermodynamically stable product. The reaction retains the stronger C=O bond at the expense of the weaker C=C π bond. The process is slow as the β carbon is less electrophilic than the carbonyl carbon.
Direct addition products are formed faster owing to...

