Phenyl methyl ether, cleavage

Repeat this analysis for the reaction of phenyl methyl ether with HI leading to phenol and methyl iodide or methanol and phenyl iodide and involving protonated phenyl methyl ether as an intermediate. (Note In this case, the appropriate empty molecular orbital is LUMO+2 the LUMO is concentrated primarily on the CO bond.) Which reaction, with ethyl propyl ether or phenyl methyl ether, appears to be more likely to give selective ether cleavage ... 

Many CuO-NaOH oxidation studies for lignin and humic acids show that copper oxide does not affect cleavage of phenyl methyl ether. However, we have found that about 50% of methoxy groups are cleaved under various conditions see Table V). 

Homoallyl ethers or sulfides.1 gem-Methoxy(phenylthio)alkanes (2), prepared by reaction of 1 with alkyl halides, react with allyltributyltin compounds in the presence of a Lewis acid to form either homoallyl methyl ethers or homoallyl phenyl sulfides. Use of BF3 etherate results in selective cleavage of the phenylthio group to provide homoallyl ethers, whereas TiCl effects cleavage of the methoxy group with formation of homoallyl sulfides. 

The first stereochemical study of the cleavage of a cyclopropane derivative by a mercuric salt was reported by DeBoer and DePuy 22). By the series of reactions given (Eq. (30)), they showed that 1-phenyl-cts, fyaws-2,3-dimethylcyclopropanol 33) and l-phenyl- ra s, methyl ethers, react with mercuric acetate in acetic acid exclusively with inversion of configuration at the carbon to which the mercury becomes attached. More recently... 

Photolysis of benzene solutions of l-methoxycarbonyl-2-naphthylmethyl 2,6-di-methyl substituted phenyl ethers induces C-O cleavage with formation of 2,4-cyclohexadienone intermediates which are subsequently photo-rearranged into meta substituted phenols. In methanol, 9-anthrylmethoxy-pyrid-2-one or l-pyrenylmethoxypyrid-2-one undergo photoheterolysis to give the C-O heterolysis products l-hydroxypyrid-2-one and the arylmethyl methyl ether, together with 2-pyridone, aryl-substituted methanol and aryl aldehyde derived from homolysis of the N-O bond. Evidence shows that an intramolecular exciplex plays a crucial role in C-O bond heterolysis. 

The phenyl coumaran, dihydro-dehydro-di- oeugenol (XXVIIa) and its methyl ether (XVIIb) reacted via cleavage of the B-ring, forming a dilactone (Figure... 

The use of the thioacetal products as electrophiles in Lewis acid-promoted reactions of allyl- and propargylstannanes allows access to three-carbon homologated methyl ethers or phenyl sulfides (eq 9). Employment of boron trifluoride etherate as the Lewis acid results in the selective cleavage of the phenylthio group to provide ether products. Similarly, the use of titanium(IV) chloride results in cleavage of the methoxy group and formation of... 

The oxidative cleavage of ethers to give carbonyl compounds has been demonstrated using UFe (readily available deficient in U) as oxidant. The reaction is regiospecific with methyl ethers (89 90). Phenyl thioethers have also been shown to undergo oxidative cleavage via a-chlorination (Scheme 41) giving, as shown, a route from alkenes or alkyl halides to aldehydes. 

The preparation of monotritiomethyl iodide by catalytic tritiodehalogenation of bis-chloromethyl ether, chloromethyl 4-phenylbenzoate or chloromethyl phenyl sulfide with tritium gas over 10% Pd/C in ethyl acetate or DMF in the presence of a tertiary amine, and subsequent cleavage of the resulting [ H]methyl ether, ester or sulfide is addressed in Section 4.2.1 Yields are usually in the range of 30-60%. 

The difference in the electron affinity between light and heavy isotopic isomers is, in other words, the difference in the stability of their anion-radicals. Such a difference gives a valuable tool for use in probing the chemistry of anion-radicals. The difference in the stability of the ring-deuterated and ring-nondeuterated arene anion-radicals has been employed to examine the transition states for the one-electron-promoted cleavage of naphthyl methyl phenyl ether and naphthyl benzyl ether (Guthrie and Shi 1990). In this reaction, the potassium salt of fluoranthene anion-radical was an electron donor ... 

Our final example is a base-labile 4-(phenylsulfonyl)methyl-l,3-dioxolane protecting group for aldehydes and ketones.4 Protection is carried out by the reaction of diol 17,1 (obtained by dihydroxylation of ally phenyl sulfone) with a carbonyl compound in the presence of pyridinium p-toluene sulfonate [Scheme 2.17], Cleavage is accomplished by treatment with DBU. /erf-Butyldimethylsilyl ethers, p-toluenesulfonate esters, tetrahydropyranyl ethers, carboxylic esters and benzoates are well tolerated. A disadvantage to the use of 17.1 is the introduc-... 

Alkylation of fl-aryleyclopentanones. Addition of 10 mole% of CuCN to the lithium enolate prepared from /3-arylcyclopentanones and LDA increases the amount of the less stable product of alkylation. Polyalkylation is also suppressed. Similar results are obtained when methyl- or phenylcopper is added to the enolate prepared by alkyUithium cleavage of trimethylsilyl enol ethers. The mechanism by which Cu(I) influences these alkylations is not as yet understood. The regiospecificity of enolate formation in the example Illustrated in equation (I) has been attributed to a directing efiect of the proximate phenyl group. This effect is also observed in the deprotonation of -arylcyclohexanones. Quantitative, but not qualitative, differences exist between five- and six-membered rings, probably because of conformational differences. ... 

X 10 s ) and the phenyl (ki = 1 x lO s ) derivatives to be made at 30 C in 2,2 -diethoxydiethyl ether the cleavage to form the coordinatively unsaturated intermediate occurs more readily for the methyl-manganese bond than for the phenyl derivative. In general, phenyl-metal bonds are stronger than methyl-metal bonds... 

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