## Addition of radicals to unsymetrically substituted double bonds can in principle either lead to the thermodynamically more stable products ("Markownikow route", M) or the less stable products ("anti-Markownikow route",A).
Kinetics and mechanism of some vinyl radical cyclisations
โ Scribed by Athelstan L.J. Beckwith; Dennis M. O'Shea
- Publisher
- Elsevier Science
- Year
- 1986
- Tongue
- French
- Weight
- 228 KB
- Volume
- 27
- Category
- Article
- ISSN
- 0040-4039
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โฆ Synopsis
The vinyl radicals 2a, 2b, and 11 each undergo fast exe ring closure to give 5a, 5b, and 12, the first two of which readily rearrange to ring-expanded radicals.
๐ SIMILAR VOLUMES
The Michael type addition of vinyl radicals on to the enone double bond was realised in Wieland-Miescher ketone derivatives leading to the formation of functionalised propellanes.
The kinetics and mechanism of the gaseous reaction of vinyl radicals with molecular oxygen have been studied at 296 K. The products formed are HCO and H2C0. The rate constant is 1.0 X 10-r' cm3 molecule-' s-\* and is independent of pressure between 0.4 and 4 Torr.
Vinyl and isopropyl radicals were generated by the pyrolysis of azoisopropane in the presence of acrolein at 473-563 K. Reaction products were analyzed by gas chromatography. Rate constant ratios k , / k , = 0.02 lr 0.01 and k 4 / k 3 : 0.01 f 0.005 are suggested for the following reactions: (1) T