Radicals olefin

Alkyl mercuric hydrides are generated in situ by reduction of an alkyl mercuric salt with sodium borohydridc (Scheme 3.91). Their use as radical traps was first reported by Hill and Whitesides491 and developed for the study of radical-olefin reactions by Giese,489490 Tirrell492 and coworkers. Careful choice of reagents and conditions provides excellent yields of adducts of nucleophilic radicals (e.g. -hexyl, cyclohexyl, /-butyl, alkoxyalkyl) to electron-deficient monomers (e.g. acrylics). 

Albini and co-workers were able to trap radicals by alkenes giving rise to two processes, namely the radical olefin addition-aromatic substitution and the addi-... 

Scheme 17 Radical addition to aUcenes versus radical olefin addition-aromatic substitution reaction.

The first step in the peroxide-induced reaction is the decomposition of the peroxide to form a free radical. The oxygen-induced reaction may involve the intermediate formation of a peroxide or a free radical olefin-oxygen addition product. (In the case of thermal and photochemical reactions, the free radical may be formed by the opening up of the double bond or, more probably, by dissociation of a carbon-hydrogen bond in metal alkyl-induced reactions, decomposition of the metal alkyl yields alkyl radicals.)... 

Nucleophilic 1,4-addition to a,p-unsaturated carbonyl Bernardi 1990b Radical-olefin addition Bertrand 1995... 

Scheme 18. Cobalt-mediated radical olefin couplings. Synthesis of functionalized styrene derivatives...

ROCAS radical olefin combination aromatic substitution... 

Reaction of trichloroacetyl isocyanate (3 equivalents) in p-xylene at reflux for 3 days with norbornenes gave, after base treatment, the 2-cyanonorborn-2-ene derivative, e.g. (407) from norbornene itself. The known [4 -t- 2] cycloadduct is not formed reaction is thought to occur by way of the unsaturated imide (408), itself possibly the result of base-promoted disproportionation of an initial [2 + 2] adduct. Decomposition of t-butylazodiphenylcarbinol in benzene occurs by a radical chain mechanism involving t-butyl radicals olefinic compounds act as radical traps norbornene, for example, is hydro-t-butylated to give exo-2-t-butylnorbomane. Stable cyclic... 

Vinyl vl-n l [ISV, r. L vinum wind] (1863) n. The unsaturated, univalent radical CFl2 CH- derived from ethylene which is the basis for all vinyl plastics. The name vinyl is used when the open bond is filled by anything but H (ethene) or a hydrocarbon radical (olefin). 

I he ethylchloro compound produced in the first alkylation is moderately stable when pure but the diethyl Ti(lV) compound decomposes readily to give a Ti(IIl) compound and products derived from the ethyl radical. Olefin elimination from the ethyltitanium(III) complex presumably gives a hydride that can react further to give the observed dihydrido complex. 

Y. Sendoda and Y. Ono, J. Chem. Soc., Faraday Trans. 1, 1980, 76, 435 Free radical olefin isomerization on siloxene. 

Albini and co-workers have developed another pathway that is formally related to the photo-NOCAS reaction. The photochemical radical-olefin combination, aromatic substitution (photo-ROCAS) reaction involves the regioselective combination of a radical, an olefin, and an arene via a PET pathway... 

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