92669-93-7Relevant academic research and scientific papers
Metalation in hydrocarbon solvents: The mechanistic aspects of substrate-promoted ortho-metalations
Slocum,Dumbris, Seth,Brown, Scott,Jackson, Gina,LaMastus, Roslyn,Mullins, Elwood,Ray, Jonathan,Shelton, Phillip,Walstrom, Amy,Wilcox, J. Micah,Holman
, p. 8275 - 8284 (2007/10/03)
The methoxy-substituted aromatic reagents 1,2- and 1,3-dimethoxybenzene (1,2-DMB and 1,3-DMB) and 1,2,4-trimethoxybenzene (1,2,4-TMB) each undergo directed ortho-metalation in high yield in n-BuLi/hydrocarbon media without the aid of a catalyst. These rea
Method for orthometalation of a carbocyclic aromatic derivative bearing at least an electron donor group
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Page column 8, (2010/01/31)
The invention concerns a method for orthometalation of a carbocyclic aromatic derivative bearing at least an electron donor group, characterised in that it consists in reacting said carbocyclic aromatic derivative with an efficient amount of at least one alkaline metal in the presence of a compound of formula (I): RX, wherein: R represents a hydrocarbon radical having 1 to 20 carbon atoms which can be a saturated or unsaturated, linear or branched, acyclic aliphatic radical; a saturated or unsaturated, monocyclic or polycyclic cycloaliphatic radical; a saturated or unsaturated, linear or branched aliphatic radical bearing a cyclic substituent; and X represents a bromine or chlorine atom.
Photochemical protodesilylation of 2-R3Si-1,3-dimethoxybenzenes. Direct observation of β-silyl-substituted cyclohexadienyl cations
Lew, Calvin S. Q.,McClelland, Robert A.
, p. 11516 - 11520 (2007/10/02)
Irradiation (254 nm) of the title compounds 5 (R3Si = Me3Si, Ph2MeSi, and 4-XC6H4Me2Si with X = 4-MeO, 4-Me, H, 4-F, and 4-Cl) in 1,1,1,3,3,3-hexafluoroisopropyl alcohol (HFIP) results in q
Regioselective Reductive Electrophilic Substitution of 1,2,3-Trimethoxybenzene and Its 5-Alkyl-Substituted Homologues
Azzena, Ugo,Denurra, Teresa,Melloni, Giovanni,Piroddi, Anna Maria
, p. 5386 - 5390 (2007/10/02)
The methoxy group in the 2-position of 1,2,3-trimethoxybenzene (1) can be regioselectively removed by electron transfer from alkali metals and replaced with a variety of electrophiles in a one-pot procedure, affording 2-substituted resorcinol dimethyl ethers.The usefulness of this synthetic method is illustrated by numerous examples.This reaction procedure has been successfully extended to the 5-methyl-substituted homologue (2), but limitations occur with the higher homologue 1-pentyl-3,4,5-trimethoxybenzene (3).Investigations on the mechanism of demethoxylation, with the aid of labeling experiments, provided clear evidence for the intermediacy of aryl radicals and explained the low yields obtained in the reductive electrophilic substitution of compound 3.
Multinuclear NMR spectroscopic studies of aryltrimethylsilanes and aryldimethylphosphaneboranes
Albanese, Joseph A.,Gingrich, Diane E.,Schaeffer, Charles D. Jr.,Coley, Suzanne M.,Otter, Julie C.,et al.
, p. 23 - 36 (2007/10/02)
Proton, boron-11, carbon-13, silicon-29, and phosphorus-31 NMR chemical shifts and coupling constants are reported for nine ortho- and 2,6-disubstituted aryltrimethylsilanes and five similarly substituted aryldimethylphosphaneboranes.Resonances in the natural-abundance carbon-13 NMR spectra for both sets of derivatives are assigned on the basis of additivity relationships, proton-coupled spectra, and relative magnitudes of 31P-13C)> coupling constants.Carbon-13 chemical shifts and 1J(13C-1H)> coupling constants indicate that the P(BH3)(CH3)2 group is electron-withdrawing.The 13C chemical shifts of aryl C(5) carbons can be attributed to steric inhibition of resonance of about the same magnitude as that produced by ortho-Si(CH3)3.Chemical shift and coupling constant data from previous work are expanded in terms of Taft's dual substituent constants ?1 and ?R0.Least squares solutions of these equations for aryldimethylphosphaneborane derivatives provide values of 0.41 for ?1 and 0.04 for ?R0 for the P(BH3)(CH3)2 group.These constants produce reasonable agreement wit observed 13C chemical shifts and coupling constants in the ortho derivatives.
Dilithiation of Aromatic Ethers
Crowther, G. P.,Sundberg, Richard J.,Sarpeshkar, Ashok M.
, p. 4657 - 4663 (2007/10/02)
The lithiations of anisole and all the isomeric dimethoxy- and trimethoxybenzenes with 2-5 equiv of n-butyllithium/TMEDA complex have been investigated under a variety of reaction conditions.Anisole and m-dimethoxybenzene do not undergo dilithiatian, but
