Hydrocarbon Oxidation by Bis-μ-oxo Manganese Dimers: Electron Transfer, Hydride Transfer, and Hydrogen Atom Transfer Mechanisms
作者:Anna S. Larsen、Kun Wang、Mark A. Lockwood、Gordon L. Rice、Tae-Jin Won、Scott Lovell、Martin Sadílek、František Tureček、James M. Mayer
DOI:10.1021/ja020204a
日期:2002.8.1
Described here are oxidations of alkylaromatic compounds by dimanganese mu-oxo and mu-hydroxo dimers [(phen)(2)Mn(IV)(mu-O)(2)Mn(IV)(phen)(2)](4+) ([Mn(2)(O)(2)](4+)), [(phen)(2)Mn(IV)(mu-O)(2)Mn(III)(phen)(2)](3+) ([Mn(2)(O)(2)](3+)), and [(phen)(2)Mn(III)(mu-O)(mu-OH)Mn(III)(phen)(2)](3+) ([Mn(2)(O)(OH)](3+)). Dihydroanthracene, xanthene, and fluorene are oxidized by [Mn(2)(O)(2)](3+) to give anthracene
A Simple Preparation of Diarylmethanes by Oxidative Friedel-Crafts Reaction of Methyl-Substituted Benzenes with<i>o</i>-Chloranil
作者:Tomoshige Kobayashi、Sheikh Maksudur Rahman
DOI:10.1081/scc-120026326
日期:2003.12
Abstract The reaction of o-chloranil with some methyl-substituted benzenes at elevated temperature was found to be a simple and selective route toward diarylmethanes without need for prior preparation of benzyl halides.
Tonsil Actisil FF, a commercial bentonitic clay, promotes the formation of a series of electrophilic-aromatic-substitution products from para-methoxybenzyl acetate in carbon disulfide. The molecules obtained correspond to linear isomeric dimers, trimers, tetramers and a pentamer, according to their spectroscopic data. A clear indication of the title mechanistic pathway for the oligomerization growth was obtained from the analysis of a set of computational-chemistry calculations using the density-functional-theory level B3LYP/6-311++G(d,p). The corresponding conclusions were based on the computed dipole moments, the HOMO/LUMO distributions, and a natural-populations analysis of the studied molecules.
It was found that benzyl chlorides and bromides could directly react with electron‐rich arenes, which provided an example of promoter‐ and additive‐free benzylation of arenes.
New methodology for the N-alkylation of 2-amino-3-acylthiophenes
作者:Luigi Aurelio、Bernard L. Flynn、Peter J. Scammells
DOI:10.1039/c0ob01156h
日期:——
2-Amino-3-acylthiophenes are known to allosterically modulate the A1adenosine receptor and are also used as intermediates in the synthesis of therapeutic agents and pharmacophores such as thienoazepines and thienopyrimidines. The N-alkylation of 2-aminothiophenes has been notoriously difficult to accomplish under mild conditions and there are very few examples of N-alkylated 2-aminothiophenes in the literature, all of which use forcing conditions to effect the alkylation. Here we describe the synthesis of such compounds under mild conditions utilising 2-carbamoylamino and 2-acylamino-3-acylthiophenes with caesium carbonate, and tetrabutylammonium iodide in DMF.