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Benzylic Position (benzylic + position)
Selected AbstractsNew Chiral N, 5-Ligands with Thiophenyl at Benzylic Position.CHINESE JOURNAL OF CHEMISTRY, Issue 9 2002Palladium (II)-catalyzed Enantioselective Allylic Alkylation Abstract New chiral N, S-ligands with oxazoline and thiophenyl substituents at benzene ring and benzylic position have been prepared and applied in palladium-catalyzed asymmetric allylic alkylation reaction to provide the product with high yield and entantioselectivity (82%,93% ee). [source] ChemInform Abstract: Carbon,Carbon Bond Formations at the Benzylic Positions of N-Benzylxanthone Imines and N-Benzyldi-1-naphthyl Ketone Imine.CHEMINFORM, Issue 44 2009Takashi Niwa Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Metalloporphyrin/Iodine(III)-Cocatalyzed Oxygenation of Aromatic HydrocarbonsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2010Akira Yoshimura Abstract Hypervalent iodine species have a pronounced catalytic effect on the metalloporphyrin-mediated oxygenations of aromatic hydrocarbons. In particular, the oxidation of anthracene to anthraquinone with Oxone readily occurs at room temperature in aqueous acetonitrile in the presence of 5,20,mol% of iodobenzene and 5,mol% of a water-soluble iron(III)-porphyrin complex. 2- tert -Butylanthracene and phenanthrene also can be oxygenated under similar conditions in the presence of 50,mol% of iodobenzene. The oxidation of styrene in the presence of 20,mol% of iodobenzene leads to a mixture of products of epoxidation and cleavage of the double bond. Partially hydrogenated aromatic hydrocarbons (e.g., 9,10-dihydroanthracene, 1,2,3,4-tetrahydronaphthalene, and 2,3-dihydro-1H -indene) afford under these conditions products of oxidation at the benzylic position in moderate yields. The proposed mechanism for these catalytic oxidations includes two catalytic redox cycles: 1) initial oxidation of iodobenzene with Oxone producing the hydroxy(phenyl)iodonium ion and hydrated iodosylbenzene, and 2) the oxidation of iron(III)-porphyrin to the oxoiron(IV)-porphyrin cation-radical complex by the intermediate iodine(III) species. The oxoiron(IV)-porphyrin cation-radical complex acts as the actual oxygenating agent toward aromatic hydrocarbons. [source] Intramolecular photoreactions of thiohomophthalimides with an alkenyl group in their N -Side chain.JOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 2 2005Regioselective synthesis of heterocycle-fused isoquinoline derivatives through [2+2] photocycloaddition Upon irradiation, thiohomophthalimides with an alkenyl group in their N -side chain or at the benzylic position give tricyclic isoquinoline derivatives through regioselective intramolecular [2+2] cycloaddition or Norrish type II reaction, respectively, in good yields. [source] Application of the anionic homologous Fries-rearrangement to the synthesis of 3-alkylbenzofuran-2(3H)-onesAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 9 2008Ugo Azzena Abstract We have developed an effective organometallic-based procedure allowing the employment of 2-methylphenols as easily available starting materials in the synthesis of 3-alkylbenzofuran-2(3H)-ones. The first step of this protocol, an anionic homologous Fries-rearrangement, afforded 2-(2- tert -butyldimethylsilyloxyaryl)acetamides, which were selectively metalated and monoalkylated at the benzylic position. Acidic work-up of crude products afforded the desired heterocycles in satisfactory overall yields. Copyright © 2008 John Wiley & Sons, Ltd. [source] New Chiral N, 5-Ligands with Thiophenyl at Benzylic Position.CHINESE JOURNAL OF CHEMISTRY, Issue 9 2002Palladium (II)-catalyzed Enantioselective Allylic Alkylation Abstract New chiral N, S-ligands with oxazoline and thiophenyl substituents at benzene ring and benzylic position have been prepared and applied in palladium-catalyzed asymmetric allylic alkylation reaction to provide the product with high yield and entantioselectivity (82%,93% ee). [source] Synthesis of New Sterically Hindered AnilinesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 19 2007Barry R. Steele Abstract Ring-alkylated primary, secondary and tertiary anilines have been ethylated with ethylene at benzylic positions in a simple and inexpensive one-pot procedure which is mediated bythe use of the superbase system nBuLi/LiK(OCH2CH2NMe2)2in the presence of Mg(OCH2CH2OEt)2. Primary and secondary anilines are ethylated readily at ortho -benzylic positions but with difficulty or not at all at other positions. Tertiaryanilines are ethylated at all positions. Mono- or diethylation occurs depending on the steric constraints present.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Transannular Hydride Migration in Pseudo-Geminally Substituted [2.2]Paracyclophanes: A Vinylogous Pinacol RearrangementEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 15 2005M. Lucian Birsa Abstract A vinylogous pinacol,pinacolone rearrangement is reported that takes place although the two hydroxyl groups are formally separated by seven bonds. It involves a transannular hydride shift that occurs between the benzylic positions of the pseudo-geminally substituted [2.2]paracyclophanes 1a,c, 7, 8 and 9. Under mild acidic conditions the corresponding pseudo-geminally substituted cyclic ethers were established as stable intermediates. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Reductions of Benzene Derivatives Whose Benzylic Positions Bear Oxygen Atoms under Mild ConditionsHELVETICA CHIMICA ACTA, Issue 12 2008Abdullah Menzek Abstract Reductions of compounds whose benzylic positions bear O-atoms, such as benzyl alcohol, dibenzyl ether, styrene oxide, benzaldehyde, acetophenone, and benzophenone, to the corresponding non-conjugated dienes were performed by using t -BuOH, Li, and gaseous NH3 in THF at room temperature. In these reductions, it was observed that the functional groups at benzylic positions were reduced first. [source] Convenient methods for the synthesis of d4, d2 and d6 isotopomers of 4-(4-fluorobenzyl)piperidineJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 6 2005Ágnes Proszenyák Abstract Pure 4-(4-fluoro-[2,3,5,6- 2H4]benzyl)piperidine was prepared via the Grignard reaction of 4-fluoro-[2,3,5,6- 2H4]bromobenzene and pyridine-4-aldehyde followed by consecutive deoxygenation and heteroatomic ring saturation in the presence of palladium on carbon catalyst. An improved method for the catalytic H/D exchange in benzylic positions of 4-(4-fluorobenzyl)piperidine and its d4 derivative has also been described. Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||