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Allyl photolysis

The mechanism of thermolysis and photolysis of ethers of 3-hydroxy-1,2-benzisoxazole has also been studied. Heating of the allyl ether (43) gave minor amounts of (44) and two benzoxazoles. Photolysis of (45) in methanol gave a benzisoxazole and an iminoester, via intermediate (46). Thermolysis at 600 °C gave a benzoxazole, a benzoxazolone and cyano-phenol (Scheme 16) (71DIS(D)4483). [Pg.18]

UV irradiation of hexafluorobenzene with indene or cycloalkenes gives high yields of 2+2 adducts, which undergo further intramolecular cycloaddition to form hexafluoropolycycloalkanes [754] (equation 38) Photolysis of fluormated deriva tives of vinylbenzenes afford benzocyclobutenes, whereas allyl benzenes yield Dewar benzene-type products [755]... [Pg.926]

Interestingly, the photolysis of methyl 3-azido-2.6-difluorobenzoate (61) in diethylamine yields, in addition to the two expected 3//-azepines 62 and 63, a third azepine 64 formed by nucleophilic displacement of allylic fluorine from the 3-position by diethylamine.188 Displacement of allylic halogen from haloazepines has been noted previously.177... [Pg.151]

Sulfones are thermally very stable compounds, diaryl derivatives being more stable than alkyl aryl sulfones which, in turn, are more stable than dialkyl sulfones allyl and benzyl substituents facilitate the homolysis by lowering the C—S bond dissociation energy17. Arylazo aryl sulfones, on heating in neutral or weakly basic media at 100°C, yield an aryl and arenesulfonyl radical pair via a reversible one-bond fission followed by dediazoni-ation of the aryldiazenyl radical (see Scheme 2 below)20. However, photolysis provides a relatively easy method for generating sulfonyl radicals from compounds containing the S02 moiety. [Pg.1094]

Allyl sulphenates, rearrangement of 720-736 Allylsulphenic acids 747 Allyl sulphinates, rearrangement of 670-676 Allylsulphinyipyrazolenines, photolysis of 749... [Pg.1196]

Sulphinates 60-70 - see also Alkanesulphinates, Arenesulphinates, Thiosulphinates ally - see Allyl sulphinates chiral - see Chiral sulphinates photolysis of 1076... [Pg.1205]

Ketenes react with tertiary allylic amines in the presence of Lewis acids to give zwitterionic intermediates which undergo [3,3]-sigmatropic rearrangement [119]. Photolysis of chromium carbene complexes in the presence of tertiary amines results in similar chemistry [120]. Cyclic (Table 21) and strained allylic amines (Eq. 34) work best, while acylic amines are less reactive (Eq. 35). [Pg.190]

Allyl silanes react with epoxides, in the presence of Bp3-OEt2 to give 2-allyl alcohols. The reaction of a-bromo lactones and CH2=CHCH2Si SiMe3)3 and AIBN leads to the a-allyl lactone. " Benzyl silanes coupled with allyl silanes to give ArCH2—R derivatives in the presence of VO(OEt)Cl2 " and allyltin compounds couple with allyl silanes in the presence of SnCU. " Allyl silanes couple to the a-carbon of amines under photolysis conditions. ... [Pg.535]

Because of the exceptional C-F bond strength, the successful preparation of a-halocyclopropyl c-complexes is realized by substitution of 1-bromo-l-fluoro-trans-2,3-dimethylcyclopropane 179 with Fp [90], Silica gel column chromatography of the thus obtained cr-complex 180 results in ring opening to the alcohol 181 as a single stereoisomer. The allene complex 182 is produced by treatment with BF3OEt2, indicating that 181 is derived from 182 and water. The 7i-allyl complex 183 is formed by photolysis via a disrotatory process. [Pg.135]

Metallocyclopentenes are frequently formed in photochemical reactions of the Group 14 metal alkyls or catenates in the presence of dimethylbutadiene. This class of compound also has an extensive photochemistry82. For example, photolysis of 51 (R = H or Me) produced the allylic alcohols 52 and 53 and, for R = H, 54. These alcohols could be dehydrated over AI2O3 to give the germole 55 along with other diene compounds. [Pg.747]

The ratio of isomeric ethers is strongly affected by polar substituents which induce an asymmetric distribution of charge in allylic cations. Photolysis of methyl 2-diazo-4-phenyl-3-butenoate (20) in methanol produced 24 in large excess over 25 as the positive charge of 22 resides mainly a to phenyl (Scheme 8).19 As would be expected, proton transfer to the electron-poor carbene 21 proceeds reluctantly intramolecular addition with formation of the cyclopropene... [Pg.5]

Photolysis of vinyldiazomethane in an organic glass at 6 K leads to vinylcarbene in its triplet ground state,14,56,57 which — as is indicated by the ESR spectra — forms a pair of the s-cis and s-trans isomer. The delocalization of one unpaired electron in the rr-system is similar to that of the allyl radical, while the other unpaired electron is localized in a sp2-orbital at the carbenic C atom (see formula T-33 ).58... [Pg.125]

Photolytic. Atkinson (1985) reported a rate constant of 2.59 x 10 " cmVmolecule-sec at 298 K. Based on an atmospheric OH concentration of 1.0 x 10 molecule/cm , the reported half-life of allyl alcohol is 0.35 d. The reaction of allyl alcohol results in the OH addition to the C=C bond (Grosjean, 1997). In a similar study, Orlando et al. (2001) studied the reaction of allyl alcohol with OH radicals at 298 K. Photolysis was conducted using a xenon-arc lamp within the range of 240-400 nm in synthetic air at 700 mmHg. A rate constant of 4.5 x 10 " cm /molecule-sec was reported. Products identified were formaldehyde, glycolaldehyde, and acrolein. [Pg.88]

Photolytic. Distilled water irradiated with UV light (X = 290 nm) yielded the following photolysis products 2-chloro-l-propanol, allyl chloride, allyl alcohol, and acetone. The photolysis half-life in distilled water is 50 min, but in distilled water containing hydrogen peroxide, the half-life decreased to <30 min (Milano et al, 1988). [Pg.433]

Radical-initiated allylic bromination using NBS, and catalytic AIBN as initiator or NBS under photolysis. [Pg.628]

In the thermolysis and photolysis in alkenes, the diazoazoles gave allylic insertion as a general reaction, although vinylic insertion and addition to give spirocyclopropane adducts were also observed. Thermolysis and... [Pg.88]

Thermolysis and/or photolysis of 4 in aliphatic halides resulted in the formation of the corresponding 1,2-addition products (73JA2695). Photolysis in cyclohexene gave the 2-cyclohexenylimidazole by allylic insertion, whereas insubstituted butenes it led to no isolable products [80DIS(B)(40)3747],... [Pg.106]


See other pages where Allyl photolysis is mentioned: [Pg.384]    [Pg.528]    [Pg.175]    [Pg.176]    [Pg.215]    [Pg.226]    [Pg.223]    [Pg.405]    [Pg.406]    [Pg.193]    [Pg.117]    [Pg.202]    [Pg.24]    [Pg.253]    [Pg.234]    [Pg.214]    [Pg.639]    [Pg.7]    [Pg.24]    [Pg.166]    [Pg.90]    [Pg.11]    [Pg.591]    [Pg.13]    [Pg.25]    [Pg.590]    [Pg.1151]    [Pg.220]    [Pg.193]   
See also in sourсe #XX -- [ Pg.212 ]




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Allyl azides, photolysis

Allyl chloride, photolysis

Allyl iodide, photolysis

Allylic alcohols, photolysis

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