The Kinetic Solvent Effect on 1,3-Dipolar Cycloaddition of 2,2,5,5-Tetramethyl-3-imidazoline-3-oxide-1-oxyl
Sergey A Cherkasov1,2, Polina M Kaletina1,2, Yuliya F Polienko1
1N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, 9 Lavrentiev Ave., Novosibirsk, 63009, Russia.
Abstract:
The use of 2,2,5,5-tetramethyl-3-imidazoline-3-oxide-1-oxyl (1) as a controlling agent in Nitroxide Mediated Polymerization allows for activation of alkoxyamine homolysis by 1,3-dipolar cycloaddition of a vinyl monomer [Edeleva et al. Chem. Commun. 2019, 55, 190-193]. Polymerization can be carried out in a medium with different polarity and hydrogen bonding capacity which affects the rate of 1,3-dipolar cycloaddition reaction. In the present study, the solvent effect on the rate of this reaction was investigated by the electron paramagnetic resonance and density functional theory for the six different dipolarophiles, e. g. styrene, n-butyl acrylate, acrylonitrile, methyl vinyl ketone, maleic anhydride, and N-phenyl maleimide. The rate of 1,3 dipolar cycloaddition of non-polar styrene was found to be slightly dependent on solvent, while one order of magnitude decrease in rate coefficient is observed for other dipolarophiles when going from hexane to methanol.
More Related Videos
05:15Solid-phase Synthesis of [4.4] Spirocyclic Oximes
Published on: February 6, 2019
06:31Highly Stereoselective Synthesis of 1,6-Ketoesters Mediated by Ionic Liquids: A Three-component Reaction Enabling Rapid Access to a New Class of Low Molecular Weight Gelators
Published on: November 27, 2015
Related Concept Videos
Cycloaddition Reactions: MO Requirements for Thermal Activation
Cycloaddition Reactions: Overview
Cycloaddition Reactions: MO Requirements for Photochemical Activation
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.
Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
