60040-82-6Relevant academic research and scientific papers
Electrochemical reduction of methyl 2-bromomethylbenzoate at carbon cathodes in dimethylformamide containingwater
Allen, Caroline R.,Brown, Drew K.,Potts, Jessica L.,Ji, Chang
, p. G3069-G3072 (2013/07/05)
Cyclic voltammetry and controlled-potential electrolysis have been employed to examine the electrochemical reduction of methyl 2-bromomethylbenzoate at carbon cathodes in dimethylformamide (DMF) containing tetramethylammonium tetrafluoroborate (TMABF4). A cyclic voltammogram for the reduction of the substrate exhibits one irreversible cathodic wave with a peak potential of -1.45 V vs. SCE, which is due to the two-electron cleavage of the benzylic carbon-bromine bond. The corresponding reductive peak current also increases incrementally with the amount of water in DMF. Bulk electrolyses of methyl 2-bromomethylbenzoate have been carried out at -1.85 V vs. SCE with different concentrations of water in the solvent. The reduction process involves carbanion intermediates to afford various products including phthalide, which is generated via intramolecular cyclization that is affected by the presence of water. Detailed mechanism for the electrochemical reaction is proposed and further studied by isotope incorporation experiment.
α,α-Dimethoxy-o-xylylene (5-(Dimethoxymethylene)-6-methylene-1,3-cyclohexadiene): Formation by 1,4-Elimination and Electrocyclic Routes and Reactions
Moss, Randall J.,White, Russell O.,Rickborn, Bruce
, p. 5132 - 5139 (2007/10/02)
The title reactive intermediate 4, which features an unprecedented (Z)-alkoxy substituent, is generated in two independent ways.The ortho ester 5 undergoes 1,4-elimination on treatment with lithium diisopropylamide, at convenient rates in the temperature range 50-70 deg C.In the absence of added dienophile, 4 generated in this manner forms a spiro dimer and a dimer, both involving bonding between the two unsubstituted methylene groups.Diels-Alder adducts of 4 with norbornene (NB), norbornadiene, and cyclopentene are described.The ketal 8 formed from 4 and NB undergoes further 1,4-elimination, generating a new o-xylylene which in turn adds a second NB to yield the novel bis-adduct 11.Thermal opening of α,α-dimethoxybenzocyclobutene (6) is also used to generate 4.Rate constants for this reaction were determined over the temperature range 132-168 deg C, through the use of N-phenylmaleimide, which efficiently traps the intermediate, thereby preventing reclosure to 6 and other decomposition reactions.The Ea for this electrocyclic opening is 33.6 kcal/mol; comparative data from the literature are discussed.In the absence of a dienophile, 4 generated in this way recloses to 6 as its major reaction pathway but also undergoes an unusual rearrangement to form methyl o-ethylbenzoate (26).The overall rate of this reaction is ca. one-tenth that of the opening of 6 to 4 and restricts the range of dienophiles which can be used to trap 4 generated from 6.For example, even at the lowest temperature (132 deg C) needed to observe electrocyclic opening, and in the presence of a very large excess of NB, competitive cycloadduct formation and rearrangement to 26 are observed.Flash vacuum pyrolysis of 6 was also briefly examined.
REDUCTIVE COUPLING OF BENZYL HALIDES USING NICKEL(0)-COMPLEX GENERATED IN SITU IN THE PRESENCE OF TETRAETHYLAMMONIUM IODIDE, A SIMPLE AND CONVENIENT SYNTHESIS OF BIBENZYLS
Iyoda, Masahiko,Sakaitani, Masahiro,Otsuka, Hiroki,Oda, Masaji
, p. 127 - 130 (2007/10/02)
Zerovalent nickel complex generated in situ by reduction of NiBr2(PPh3)2 with zinc powder in the presence of Et4NI was found to be an effective catalyst for homo-coupling of benzyl halides.The catalytic reactions proceeded smoothly in various solvents under mild conditions to afford dehalogenative-coupling products in good to high yields.
