Radical cumyloxyl

Avila DA, Ingold Kl, Lusztyk J, Green WFI, Procopio DR (1995) Dramatic solvent effects on the absolute rate constant for abstraction of the hydroxylic hydrogen atom from (erf-butyl hydroperoxide and phenol by the cumyloxyl radical. The role of hydrogen bonding. J Am Chem Soc 117 2929-2930... 

TABLE 10. Solvent Effects on Rates of H Abstraction (ka) and p-Scission (kp) of Cumyloxyl Radicals (CumO ). Data from (327). 

Results are selected from Reference 191. RO is tert-butoxyl radical with a-Toc, and cumyloxyl radical with phenol. 

Results are selected from Reference 188. RO" is the cumyloxyl radical. 

Ingold and coworkers have also expressed a kinetic equation (equation 43) to determine the equilibrium constant ( T ) for hydrogen bonding between the phenolic antioxidant and dilute HBA solvent. A, if rate constants in neat HBA and non-HBA solvent, nA, CCI4 in this example, are known. For this study they monitored hydrogen-atom transfer from the antioxidant phenol to cumyloxyl radicals . ... 

Crown ethers, of caUxarenes 1396-1399—see also Cahx[4]crowns Cryptands—see Calixcryptands Crystal effects, on LD IR spectroscopy 368 Crystal stmcture determination, computer-based 549 C—S bond fission, homolytic 1079 Cumene, as substrate for antioxidants 859 4-Cumyl-l-naphthol, formation of 607 Cumyloxyl radical 877 Cumylphenols, formation of 607 4-Cumylresorcinol, formation of 607 Curcumin 867, 868, 870 Curie-point carbon-isotope-ratio mass spectrometry 303 Curie-point Py/GC/MS 303 Curie-point pyroUzer 938 p-Cyanophenol,... 

Rate constants for some alkoxyl radical fragmentations are shown in Fig. 9. The tcrt-butoxyl radical (26) fragmentation to acetone and the methyl radical has been studied for years, but the rate constant shown below is from a very recent work that employed time-resolved ESR methods [2]. The cumyloxyl radical (27) fragmentation was studied directly by LFP methods, taking advantage of the IR and UV absorbances of this radical [57]. The rate constants for the reversible ring opening of the cyclopentyloxyl radical (28) were determined by competition kinetics [58], and one should note that the kinetic values are at 80 °C. 

Salamone, M., Milan, M., DiLabio, G. A., Bietti, M. (2014). Absolute Rate Constants for Hydrogen Atom Transfer from Tertiary Amides to the Cumyloxyl Radical Evaluating the Role of Stereoelectronic Effects. The Journal of Organic Chemistry, 79, 7179-7184. 

For tert-butoxyl radicals, except otherwise indicated. From Table 3.4. From Table 3.6. From Ref. [26] in benzene/di-tert-butoxyperoxide (1/2). "From Ref. [34] in n-hexane. From Ref. [206] in benzene for cyclohexene see also Ref. [211]. From Ref. [288] in benzene/di-tert-butoxyperoxide (1/2). Rate constants in benzene for reaction with cumyloxyl radicals are 4.6 X 10 for 1-octene,... 

X 10 for cyclohexene, 2.3 x 10 for 1,3-cyclooctadiene, 2.0 x 10 for cyclohexane all in M- s" from Ref. [288]. Rate constant for 2,5-dimethyl-2,4-hexadiene refers to cumyloxyl in benzene. From Table 3.9. From Ref. [215] in acetonitrile. From Ref. [256] in acetonitrile for cyclohexene see also Refs. [258,259]. From Ref. [33] see also Ref. [72] in isooctane. Calculated from fluorescence lifetime in neat ethanol based on a lifetime in gas phase of 1030 ns. "From Ref. [230] in benzene/di-tert-butoxyperoxide (1/2). "From Ref. [289] in benzene. °From Ref. [288] in chlorobenzene Ref. [290] in benzene/di-ferf-butoxyperoxide (1/2). Values for cumyloxyl radicals can be found in Refs. [288,291,292]. PFrom Ref. [74] in benzene. From Ref. [291] in benzene see also Refs. [74,293]. From Ref. [232] in benzene at 37°C. Value for diethylsulfide. From Ref. [294] in benzene." From Ref. [70] in neat acetone. For quenching of triplet acetone by n-propylamine and triethylamine in acetonitrile see also Refs. [172,271]. In the case of alkoxyl radicals the values for cumyloxyl radicals are reported. From Refs. [29,231] reaction with fert-butoxyl radicals in benzene/di-tert-butoxyperoxide (1/2). Values not reported in table n-propylamine 1.6 x 10 M s, diethylamine ... 

CU2O could catalyze oxidative alkylarylation of acrylamides with simple alkanes to alkyl-substituted oxindoles using dicumyl peroxide (DCP) as radical initiator. Alkyl radical could be formed via hydrogen abstraction reaction with cumyloxyl radical which is generated from the homolysis of DCP. Then alkyl radical reacts with C=C bond followed by cyclization to benzene core and oxidation to give the alkyl-substituted oxindoles. Selective activation of unactivated C(sp )-H and C(sp2)-H bonds by one single step is achieved in this transformation [70] (Scheme 8.33). 

Banks, J.T. and Scaiano, J.C., The Laser-Drop Method A New Approach to Induce Multiple Photon Chemistry with Pulsed Lasers. Examples Involving Reactions of Diphenyhnethyl and Cumyloxyl Radicals, /. Am. Chem. Soc., 115, 6409, 1993. 

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