Benzyl peroxides formation

It seemed prudent that the same ethers be examined in the absence of potentially labile functionality, thus removal of unsaturation in 262 and 263 was considered. Hydrogenation of 259 over Pd/C or Pt was unsuccessful in either case reduction of the peroxide group was problematical. Hydrogenation over Wilkinson s catalyst gave a new product, but with the unsaturation retained. While selective alkene hydrogenation can sometimes be achieved in the presence of a peroxide bond, the double bond of 259 was apparently too hindered in this case. Diimide, on the other hand, worked reasonably well for this reduction. Thus, treatment of 259 in dichlo-romethane solution with potassium azodicarboxylate followed by addition of acetic acid led, after several days, to roughly 60% conversion of 259 to the saturated version, 264. Now, ether formation as before provided the saturated methyl and benzyl ethers 265 and 266, respectively, in good yields. 

The formation of oxygen- and carbon-centered radicals by the thermolysis of peroxides or azo compounds is well known. Today, these compounds have been also used as radical initiators. For example, treatment of a CC14 solution of toluene and Af-bromosuccinimide (NBS) in the presence of a catalytic amount of benzoyl peroxide in refluxing conditions gives benzyl bromide in good yield as shown in Scheme 1.5. This is called the Wohl-Ziegler reaction. 

Benzoylbenzene, 458 Benzoyl Peroxide, 43 Benzyl Acetate, 458, 570, 608 Benzyl Alcohol, 458, 570, 646 Benzyl Benzoate, 458, 647 Benzyl Butyrate, 458, 647 Benzyl n-Butyrate, 458 Benzyl Cinnamate, 458, 647 Benzyl Formate, 460, 608 Benzyl Isobutyrate, 460, 608 Benzyl Isovalerate, 460, 648, (Sl)60 Benzyl 3-Methyl Butyrate, 460 Benzyl 2-Methyl Propionate, 460 Benzyl Phenylacetate, 460, 608 Benzyl Propanoate, 460 Benzyl Propionate, 648 Benzyl Salicylate, 460, 682 Bergamot Oil, Coldpressed, 44, 575 beta Cyclodextrin, (Sl)15 Beta-1,3-Glucan, (S3)15 BHA, 44 BHT, 45... 

The authors proposed that the peroxide is decomposed by the metal catalysts to the ketone and alcohol in a manner similar to that previously reported (30-34). This later system was also reactive toward adamantane (giving a high 3°/2° carbon activation ratio of 3.5) and other saturated alkanes. These catalysts also oxidize toluene at both the aliphatic and aromatic carbons (ratio benzylic/aromatic = 3.4 0.9) (Table IV). Activation of the aromatic ring was attributed to the formation of hydroxyl radicals. 

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