Oxidation benzyl phenyl

Diphenylthiirene 1-oxide reacts with hydroxylamine to give the oxime of benzyl phenyl ketone (79JA390). The reaction probably occurs by addition to the carbon-carbon double bond followed by loss of sulfur monoxide (Scheme 80). Dimethylamine adds to the double bond of 2,3-diphenylthiirene 1,1-dioxide with loss of sulfur dioxide (Scheme 81) (75JOC3189). Azide ion gives seven products, one of which involves cleavage of the carbon-carbon bond of an intermediate cycloadduct (Scheme 81) (80JOC2604). 

Oxidation of phenyl hexyl sulphide with sodium metaperiodate gave also only a trace amount of the corresponding sulphoxide72. On the other hand, Hall and coworkers73 prepared benzylpenicillin and phenoxymethyl penicillin sulphoxides from the corresponding benzyl esters by oxidation with sodium metaperiodate in dioxane solution with a phosphate buffer. A general procedure for the synthesis of penicillin sulphoxides was reported later by Essery and coworkers74 which consists in the direct oxidation of penicillins or their salts with sodium metaperiodate in aqueous solution at pH 6.5-7.0. 1-Butadienyl phenyl sulphoxide 4475 and a-phosphoryl sulphoxides 4576 were also prepared by the same procedure. 

Ketones are oxidatively cleaved by Cr(VI) or Mn(VII) reagents. The reaction is sometimes of utility in the synthesis of difunctional molecules by ring cleavage. The mechanism for both reagents is believed to involve an enol intermediate.206 A study involving both kinetic data and quantitative product studies has permitted a fairly complete description of the Cr(VI) oxidation of benzyl phenyl ketone.207 The products include both oxidative-cleavage products and benzil, 7, which results from oxidation a to the carbonyl. In addition, the dimeric product 8, which is suggestive of radical intermediates, is formed under some conditions. 

With this method styrene derivatives are oxidized in very good yields (complete conversion at 56 °C after 2-5 hours), whereas aliphatic alkenes require longer reaction time (8-20 h) and increased amounts of oxidant (3.5 eq.), and afford methyl ketones in moderate to good yields. Besides terminal olefins also stilbene and ethyl cinnamate have been converted to benzyl phenyl ketone and /3-ketoester. The catalyst solution can be reused 8 times without decrease in yield. 

Catalytic oxidations of sulfides were carried out in 1,2-dichloroethane with cumyl hydroperoxide by using 10 mol % of the catalyst. The best enantioselectivity was achieved with complex 6c. However, sulfone was always produced as byproduct of the reaction. Even with a limited amount of hydroperoxide, the sulfone formation could not be avoided. For example, the reaction of methyl p-tolyl sulfide using 0.5 mol equiv. of cumyl hydroperoxide with respect to sulfide gave a 62 38 mixture of the corresponding (.S j-sulfoxide and sulfone. The reaction of benzyl phenyl sulfide led to the formation of (5)-sulfoxide (84% ee) and sulfone ([sulfox-ide]/[sulfone] = 77 23). It was established that sulfone was produced from the early stages of the reaction. It was also demonstrated that some kinetic resolution of the sulfoxide cooperated with the enantioselective oxidation of the sulfide. A unique feature of this oxidation system, as compared to those using various Ti(IV)/(DET) complexes, is the insensitivity of the enantioselectivity (40-60% ee at 0°C) to the nature of the alkyl group of sulfides Ar-S-alkyl. 

Thiazoline-azetidinones 1 derived from penicillins G and V4) are potential intermediates for penicillin-cephalosporin conversion, where the oxidative functionalization of the methyl group of the 3-methyl-3-butenoate moiety is an essential step. The direct chlorination of 1 with chlorine (25 °C, 3 days) or /-butyl hypochlorite (—60% yields) gives the corresponding chlorinated compounds 2, bearing benzyl, phenyl, p-tolyl, and phenoxymethyl groups as the R3 substituents 5). 

Flavone (2-phenylchromone) (68) is more labile to hydrogenolysis at the ether linkage than are 2-alkylchromones because it may be considered to be a benzyl-phenyl-type ether. Hydrogenation of flavone over copper-chromium oxide at 140-150°C gave 4-flavanol in a maximum yield of 65% in a very rapid reaction (8 min), while the flavanol was obtained in a yield of 85% in rapid hydrogenation of flavanone (69) at 135-145°C or in a yield of 93% in the hydrogenation in a dilute ethanol solution at 120-135°C (eq. 12.123).233... 

Alkaline hydrogen peroxide does not attack alkyl side chains directly, but it can be very useful for the conversion of the aromatic aldehyde to the carboxylic acid in the side chain oxidation sequence. The chemistry is covered in Section 6.1. Peracids usually do not attack alkyl side chains, but can oxidize benzylic alcohols and aldehydes to the carboxylic acids and benzylic ketones to phenyl ester. These reactions are covered in sections on alcohol (5), aldehyde (6.1) and ketone (6.2) oxidation. 

Sodium periodate is also frequently used as an oxidant for selenides, the reaction proceeds slowly in aqueous methanol. Various selenoxides such as methyl phenyl and benzyl phenyl selenoxides, (3B), (39),2 (40) and 2-azidocyclohexyl phenyl selenoxide have been isolated in this way. Other solvents and reaction conditions may also be employed. " °... 

Benzyl-phenyl- IV/ld, 547 (Selen-oxid-Red.) IX, 983 (alkylier, Se-Se-Spalt.)... 

Reaction (147) is the dominant means of oxidizing benzyl radicals. It is a slow step, so the oxidation of toluene is overall slower than that of benzene, even though the induction period for toluene is shorter. The oxidation of the phenyl radical has been discussed, so one can complete the mechanism of the oxidation of toluene by referring to that section. Figure 12 from Ref. [66] is an appropriate summary of the reactions. 

The order of ease of displacement of groups from the phosphonium salts is allyl, benzyl > phenyl > methyl > 2-phenylethyl > ethyl, higher alkyls. The usefulness of this method for the preparation of various alkyldiphenylphosphine oxides from the available triphenylphosphine is particularly noteworthy. In contrast, the preparative value of this method is diminished in cases where the carbanions correspond ing to the leaving groups on the phosphorus have approximately the same stability. In some cases the reaction is used to prepare the carbon compound (equations 9 to 14). ... 

Oxidation of diphenylcyclopropenone with m-chloroperbenzoic acid gave a mixture of benzil, diphenylacetylene and benzophenone, whereas di-r-butylcyclopropenone gave mainly 4,5-epoxy-2,2,4,5-tetramethylhexan-3-one. Alkaline hydrogen peroxide and diphenylcyclopropenone yield the same products along with benzyl phenyl ketone (equation 49). The benzyl phenyl ketone is thought to arise from addition of... 

Diphenyl selenide is oxidized with peroxyacetic acid at room temperature to diphenyl selenoxide hydrate, C6H5Se(OH)2, in 43% yield after 2 h [1198]. Benzyl phenyl selenide is oxidized to benzyl phenyl selenoxide by sodium periodate in aqueous methanol at 0 °C in 95% yield and by iodobenzene dichloride in aqueous pyridine at -40 °C in 85% yield [773]. 

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