10574-17-1Relevant articles and documents
Origin of 13C complexation shifts in the adduct formation of 2-butyl phenyl ethers with a dirhodium tetracarboxylate complex
Diaz Gomez, Edison,Duddeck, Helmut
, p. 23 - 29 (2008/09/17)
Complexation of the oxygen atom in 2-butyl phenyl ethers to a rhodium atom of the dirhodium tetracarboxylate Rh(II)2[(R)-(+)-MTPA] 4(Rh*, MTPA-H = methoxytrifluoromethylphenylaceticacid = Mosher's acid) deshields an sp3-hybridized 13C nucleus directly bonded to the ether oxygen; apparently, the inductive effect of the oxygen is enhanced when it is complexed to the rhodium atom. On the other hand, deshielding complexation shifts of aromatic ipso-carbons (α-positioned) are minute but ortho- and para-carbon signals are influenced by the resonance effect of oxygen. This effect can be modulated by further substituents at the benzene ring. In turn, this modulation of the resonance correlates linearly ith the magnitude of the inductive effect exerted on the aliphatic α-carbon atoms. Diastereomeric dispersion effects at 13C signals can be observed for most compounds, indicating that enantiodifferentiation is possible in this class of ethers. Copyright
Rearrangement Alkyl Phenyl Ethers to Alkylphenols in the Presence of Cation-exchanged Montmorillonite (Mn+-Mont)
Tateiwa, Jun-ichi,Nishimura, Takahiro,Horiuchi, Hiroki,Uemura, Sakae
, p. 3367 - 3372 (2007/10/02)
The rearrangement of alkyl phenyl ethers such as 4-phenoxybutan-2-one 1, 1-phenoxybutane 2a, 2-phenoxybutane 2b, 2-methyl-2-phenoxypropane 2c and phenoxycyclohexane 2d have been investigated in the presence of cation-exchanged montmorilonite (Mn+-mont; Mn+ = Zr4+, Al3+, Fe3+ and Zn2+).The ether 1 rearranged to 4-(4-hydroxyphenyl)butan-2-one 3 (raspberry ketone), the odour source of rasprerry, in 16-34percent GLC yield, where Zn2+-mont was the most effective catalyst.Similarly, other ethers 2a-d rearranged to the corresponding alkylphenols in up to 75percent isolated yield with good product selectivity, Al3+-mont being the catalyst of choice.Al3+-Mont was regenerated and resulted in the rearrangement of 2b, 2c and 2d.
Alkylation with Oxalic Esters. Scope and Mechanism.
Bergman, Jan,Norrby, Per-Ola,Sand, Peter
, p. 6113 - 6124 (2007/10/02)
Alkyl oxalates are well suited for use as standard synthetic reagents in N-, O-, or S-alkylations and often display an interesting regioselectivity.The mechanism seems to be a direct alkylation of the substrate anion.
FLUORIDE SALTS ON ALUMINA AS REAGENTS FOR ALKYLATION OF PHENOLS AND ALCOHOLS.
ANDO,YAMAWAKI,KAWATE,SUMI,HANAFUSA
, p. 2504 - 2507 (2007/10/02)
THE EFFECTIVENESS OF ALKALI METAL FLUORIDES IMPREGNATED ON ALUMINA AS A REAGENT FOR PROMOTING ALKYLATION WAS OPTIMIZED WITH RESPECT TO THE METAL CATION, THE AMOUNT OF IMPREGNATION, AND THE REACTION SOLVENT. POTASSIUM OR CAESIUM FLUORIDE ONALUMINA IN ACETONITRILE OR 1,2-DIMETHOXYETHANE WAS CONCLUDED TO BE THE BEST REACTION SYSTEM FOR GENERAL USE. O-ALKYLATION OF SUBSTITUTED PHENOLS, PRIMARY AND SECONDARY ALCOHOLS, AND A GLYCOL WAS CARRIED OUT MOSTLY IN GOOD YIELDS UNDER MILDCONDITIONS WITH SIMPLE EXPERIMENTAL PROCEDURES.
Ion-Molecule Complexes in Unimolecular Fragmentations of Gaseous Cations. Alkyl Phenyl Ether Molecular Ions
Morton, Thomas Hellman
, p. 1596 - 1602 (2007/10/02)
A decomposition pathway that bears a formal resemblance to first-order elimination in solution is demonstrated for parent ion fragmentations of alkyl phenyl ethers under electron impact (EI) and chemical ionization (CI).The sequence of steps in the gas phase, parent ion -> ion-molecule complex -> fragments, is analogous to first-order elimination in solution (which goes through ion pairs).Such a mechanism for expulsion of PhOH+. from molecular ions has been tested by examing neutral products from 70-eV electron bombardment of neopentyl phenyl ether in a specially constructed electron bombardment flow (EBFlow) reactor.The C5H10 isomers 2-methyl-1-butene (2) and 2-methyl-2-butene (3) are recovered in the same ratio (2/3=1.14) as is produced by gas-phase deprotonation of tert-amyl cation.This result is validated by a mass spectrometric study of deuterated analogues, for which the ratio of γ-transfer (corresponding to product 2) to α-transfer (corresponding to product 3) is calculated to be 1.46.Intermediacy of an ion-molecule complex, PhOCH2C(CH3)3+. -> .CH3CH2(CH3)2C+> -> PhOH+. + 2 or 3, predicts this outcome, where the species in brackets represents an electrostatically bound comlex of the neutral phenoxyl radical and an alkyl cation.This mechanism explains the published mass spectrometric (EI an CI) and EBFlow results for n-propyl and n-butyl phenyl ethers.Several confirmatory experiments support the intermediacy of an ion-molecule complex and rule out other interpretations of the experiment data.