- Substituent Dependence of the ?-Acceptor Induced Bond Cleavage Reactions of Benzyl Phenyl Ethers
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The relative C-O bond cleavage reaction rates (krel) of eight substituted benzyl phenyl ethers (BPE's) have been measured.These C-O bond cleavage reactions were thermally initiated by 2,3-dichloro-5,6-dicyanoquinone (DDQ).The equilibrium constants (K) for charge-transfer complex formation of these BPE's with the electron acceptors DDQ and TCNE in the solvent methylene chloride have also been determined at room temperature.The best correlation of log krel for DDQ reactions has been observed in these reactions.From this data, hydride transfer to DDQ is the rate-determining step of the reaction.
- Penn, John H.,Lin, Zhe
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p. 1554 - 1559
(2007/10/02)
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- Gas-Phase Wittig Rearrangement of Carbanions Derived from Benzyl Ethers
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The CA mass spectra of ions PhC-HOR and Ph(R)CH-O- (R = alkyl and phenyl) are very similar, suggesting that the Wittig rearrangement PhC-HOEt -> Ph(Et)CH-O- occurs in the gas phase.Major fragmentation can be interpreted in terms of 1,2-elimination of groups from the Wittig product ion.For example, 2H labeling of PhC-HOEt and Ph(Et)CH-O- show that the major processes produce Me-CH=CH-O- + C6H6 and (C6H4)-CHO + C2H6, with the latter process involving prior scrambling of phenyl hydrogens.An analogous process, Ph2CH-O- -> (C6H4)-CHO + C6H6 gives the major peak in the spectrum of "PhC-HOPh".
- Eichinger, Peter C. H.,Bowie, John H.,Blumenthal Thomas
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p. 5078 - 5082
(2007/10/02)
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