Why is vinyl anion configurationally stable but a vinyl radical configurationally unstable?

Jenkins, Paul R.; Symons, Martyn C. R.; Booth, Susan E.; Swain, Christopher J.

doi:10.1016/s0040-4039(00)92685-6

Cited by 37 publications

(26 citation statements)

References 17 publications

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“…Reactions of cis ‐aryl‐substituted alkenyl bromides also occurred in good to excellent yields with retention of the olefin geometry (Scheme , 3 u – w ). These results provide evidence that the reaction does not precede via a radical intermediate, since the vinyl radical is known to be configurationally unstable;16 a mixture of stereoisomers of the difluoromethylated alkenes would be observed if the vinyl radical was formed under the reaction conditions.…”

Section: Methodsmentioning

confidence: 78%

Pd‐Catalyzed Difluoromethylation of Vinyl Bromides, Triflates, Tosylates, and Nonaflates

Chang

Shen

2015

Chemistry A European J

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Section: Methodsmentioning

confidence: 78%

Pd‐Catalyzed Difluoromethylation of Vinyl Bromides, Triflates, Tosylates, and Nonaflates

Chang

Shen

2015

Chemistry A European J

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“…The other method is the generation of isomeric vinyl radicals from stereoisomeric E or Z α‐substituted vinylic precursors or by addition of a radical to a carbon–carbon triple bond, and comparison of the product compositions after chemical trapping. Both approaches, however, suffer from drawbacks, which make it difficult to distinguish experimentally between a configurationally unstable,5 rapidly inverting σ‐type radical (Scheme , B), effectively linear, and a π‐type, linear, vinyl radical.…”

Section: Introductionmentioning

confidence: 99%

Photochemical Generation and Structure of Vinyl Radicals

Goumans¹,

Alem²,

Lodder³

2008

Eur J Org Chem

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Photolysis of a series of E or Z stereoisomeric α-R-substituted bromostyrenes (R = CH 3 , F or CN) in methanol yields E and/ or Z stereoisomeric styrenes, which stem from the corresponding vinyl radicals. The results show that the α-Me vinyl radical is a rapidly equilibrating, bent structure, while the α-F vinyl radical is a stable bent species, in agreement with earlier thermal results. The α-CN vinyl radical is assigned as a rapidly inverting bent and not a linear species from the

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“…Thus, as suggested in Scheme 2 , a likely pathway for the formation of 9-ONA-PC 17 in the present study involves conversion of epoxy allylic radical 13 to vinyl ether radical 20 , followed by oxygen rebound from the Fe 3+ − OH pair to form hemiacetal 21 , whose rearrangement affords ONA-PC 17 and 3-nonenal. Furthermore, similar to the known reduction of the alkoxyl radical to alkoxide ion by Fe 2+ [ 19 ], Fe 2+ might reduce vinyl ether radical 20 to carbanion 22 , which would cleave to form ONA-PC 17 and vinylic anion 23 , because, unlike vinylic radicals which are unstable, vinylic anions are relatively stable [ 31 ]. Vinylic anion 23 will then be converted to 1,3-nonadiene 24 , a known product of the oxidation of sunflower oil [ 32 ] whose formation has otherwise been speculated to involve unstable vinylic radical 18 [ 25 ].…”

Section: Resultsmentioning

confidence: 99%

Formation of Aldehydic Phosphatidylcholines during the Anaerobic Decomposition of a Phosphatidylcholine Bearing the 9-Hydroperoxide of Linoleic Acid

Onyango

2016

BioMed Research International

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Lipid oxidation-derived carbonyl compounds are associated with the development of various physiological disorders. Formation of most of these products has recently been suggested to require further reactions of oxygen with lipid hydroperoxides. However, in rat and human tissues, the formation of 4-hydroxy-2-nonenal is greatly elevated during hypoxic/ischemic conditions. Furthermore, a previous study found an unexpected result that the decomposition of a phosphatidylcholine (PC) bearing the 13-hydroperoxide of linoleic acid under a nitrogen atmosphere afforded 9-oxononanoyl-PC rather than 13-oxo-9,11-tridecadienoyl-PC as the main aldehydic PC. In the present study, products of the anaerobic decomposition of a PC bearing the 9-hydroperoxide of linoleic acid were analysed by electrospray ionization mass spectrometry. 9-Oxononanoyl-PC (ONA-PC) and several well-known bioactive aldehydes including 12-oxo-9-hydroperoxy-(or oxo or hydroxy)-10-dodecenoyl-PCs were detected. Hydrolysis of the oxidized PC products, methylation of the acids obtained thereby, and subsequent gas chromatography-mass spectroscopy with electron impact ionization further confirmed structures of some of the key aldehydic PCs. Novel, hydroxyl radical-dependent mechanisms of formation of ONA-PC and peroxyl-radical dependent mechanisms of formation of the rest of the aldehydes are proposed. The latter mechanisms will mainly be relevant to tissue injury under hypoxic/anoxic conditions, while the former are relevant under both normoxia and hypoxia/anoxia.

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Why is vinyl anion configurationally stable but a vinyl radical configurationally unstable?

Cited by 37 publications

References 17 publications

Pd‐Catalyzed Difluoromethylation of Vinyl Bromides, Triflates, Tosylates, and Nonaflates

Pd‐Catalyzed Difluoromethylation of Vinyl Bromides, Triflates, Tosylates, and Nonaflates

Photochemical Generation and Structure of Vinyl Radicals

Formation of Aldehydic Phosphatidylcholines during the Anaerobic Decomposition of a Phosphatidylcholine Bearing the 9-Hydroperoxide of Linoleic Acid

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