Hydrogen Abstraction by Heteroatom-centred Radicals

The effect and role of the Cl in ozone depletion in the stratosphere have highlighted the need for knowledge of how it reacts with atmospheric species and pollutants. As a consequence, the H-abstraction reactions of Cf with a large variety of non-halogenated 

Studies examining H-abstraction by various oxygen-centred radicals have been reported. Activation energies and rate constants for the processes of abstraction from alkyl, vinyl, and aryl hydrocarbons have been calculated with abstraction from aliphatic C—FI bonds proceeding with the highest activation energies. 

One of the most popular nitroxide-based radicals (TEMPO) has been shown to abstract H-atoms fi om activated C—FI bonds. Flowever, the nitroxide itself is easily photo-degraded. In order to examine more photochemically stable alternatives to TEMPO in abstraction reactions, the related isoindoline nitroxide radical (61) has been examined. Abstractions fi om unactivated primary, secondary, and tertiary C—H alkane bonds were all achieved. 

Activation energies and rate constants for the H-abstraction reaction by H fiom simple ahphatic ketones in water has been calculated by EPR FID attenuation measurements.  

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Hydrogen Abstraction by Carbon-centred Radicals. . Hydrogen Abstraction by Heteroatom-centred Radicals... 

Hydrogen Abstraction by Heteroatom-centred (Non-halogen-centred) Radicals. 140... 

Imidoyl radicals are often prepared by the addition of carbon- or heteroatom-centred radicals to isocyanides, but can also be prepared by hydrogen atom abstraction from imines. This latter method has been adopted in a new annulation approach to quinoline synthesis. Thus, reaction of the imine 1 with phenylacetylene and di-isopropyl peroxydicarbonate in benzene at 60°C gave a mixture of the quinolines 2 and 3 in 65% yield (2 3 = 4.4). 

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