Reductive Pinacol Coupling of Aromatic Carbonyl Compounds Catalytic in Chromium(II)
作者:Aleš Svatoš、Wilhelm Boland
DOI:10.1055/s-1998-1695
日期:1998.5
Reductive coupling of aromatic and heteroaromatic aldehydes and ketones bearing different functional groups to pinacols is effectively catalysed with 1-5 mol% of Cr(II) salts or chromocene in THF/DMF mixtures in the presence of manganese powder and trialkyl chlorosilanes. Excellent dl selectivity can be achieved albeit with lower yield using trialkylsilyl chlorides with bulky substituents.
Samarium(II) iodide equivalent was generated from metallic samarium and Me3SiCl/Nal reagent in acetonitrile under ambient conditions. Dehalogenation of α-halocarbonyl compounds and reductive coupling of ketones were successfully carried out by the use of the samarium(II) species, thus generated, in acetonitrile.
在环境条件下,从金属钐和 Me3SiCl/Nal 试剂在乙腈中生成碘化钐 (II) 等价物。α-卤代羰基化合物的脱卤和酮的还原偶联成功地通过使用在乙腈中产生的钐(II)物种进行。
The Catalytic Pinacol Rearrangement of 1,2-Diols Using an Antimony(V) Salt.
作者:Tsunehiro Harada、Teruaki Mukaiyama
DOI:10.1246/cl.1992.81
日期:——
In the presence of a catalytic amount of antimony(V) chloride or antimony(V) salt generated from antimony(V) chloride and silver hexafluoroantimonate, the pinacol rearrangement of several 1,2-diols or their trimethylsilyl ethers proceeds smoothly to give the corresponding ketones in good yields.
Perrier, Serge; Sankararaman, Seth; Kochi, Jay K., Journal of the Chemical Society. Perkin transactions II, 1993, # 5, p. 825 - 837
作者:Perrier, Serge、Sankararaman, Seth、Kochi, Jay K.
DOI:——
日期:——
Acid Catalysis vs. Electron-Transfer Catalysis via Organic Cations or Cation-Radicals as the Reactive Intermediate. Are These Distinctive Mechanisms?
作者:Rajendra Rathore、Jay K. Kochi、Augusto Canavesi、Larry L. Miller、Giovanni V. Sebastiani、George W. Francis、József Szúnyog、Bengt Långström
DOI:10.3891/acta.chem.scand.52-0114
日期:——
Proton transfer to aromatic and olefinic donors (D) lends to the facile interchange of transient carbocations (DH+) and cation-radical (D+.). The same types of cation and cation-radical are reactive intermediates in the acid catalysis and the electron-transfer catalysis of such organic transformations as benzylic coupling, epoxide.-pinacol rearrangements and cis-trans isomerization of stilbenes when they are both carried out under otherwise identical reaction conditions, However, the rapid exchange of diamagnetic cations and paramagnetic cation-radicals blurs the traditional view of sepal ate electrophilic and homolytic processes, and rigorous experimental evidence is required to establish whether acid catalysis and electron-transfer catalysis actually represent distinct mechanistic categories.