Zinc oxide as a regioselective and heterogeneous catalyst for the synthesis of chalcones at room temperature
摘要:
Zinc oxide catalyzed synthesis of chalcones has been carried out under solvent-free conditions at room temperature. Activated as well as unactivated aromatics smoothly underwent Friedel-Crafts acylation with alpha,beta-unsaturated acid chlorides furnishing excellent yields of the corresponding chalcones. The zinc oxide can be recovered and reused at least three times without any appreciable loss in activity. (C) 2012 Elsevier B.V. All rights reserved.
Reaction condition controlled nickel(<scp>ii</scp>)-catalyzed C–C cross-coupling of alcohols
作者:Meng-Juan Zhang、Hong-Xi Li、David J. Young、Hai-Yan Li、Jian-Ping Lang
DOI:10.1039/c9ob00418a
日期:——
methodology employing a Ni(II) 4,6-dimethylpyrimidine-2-thiolate cluster catalyst under different reaction conditions. This catalyst could tolerate a wide range of substrates and exhibited a high activity for the annulation reaction of secondary alcohols with 2-aminobenzyl alcohols to yield quinolines. This work is an example of precise chemoselectivity control by careful choice of reaction conditions.
Ketyl Radicals Formed in Grignard Reaction. IV. Sterically Hindered Ketyl Radicals in Nuclear Replacement and Conjugate Addition
作者:Masao Okubo
DOI:10.1246/bcsj.50.2379
日期:1977.9
chloride was examined by means of ESR measurements. Both the original and the “replaced” ketyl radicals were identified, and an electron-transfer mechanism similar to that of SRN−-type reactions was proposed. Some stericallyhindered αβ-enones were also found to form detectable amounts of ketyl radicals. The factors governing the production ratio of the normal and the conjugate adduct were discussed
A Novel Formation of Phenyl-Substituted Pyridines by the Reaction of<i>N</i>-(Diphenylphosphinyl)-1-azaallyl Anions with α,β-Unsaturated Carbonyl Compounds. A New Synthetic Equivalent of Primary Vinylamines
1-propanone and 1,5-pentanedione derivatives. A plausible mechanism involving a sequence of Michael addition and intramolecular aza-Horner-Wittig reaction is described, and the 1-azaallyl anions were found to behave as a synthetic equivalent of primaryvinylamines.
Conjugate addition of grignard reagents to unsaturated ketones: gc/ms- hplc study. Isolation and oxidation of e and z enols of a ketone
作者:A.G. Pinkus、S. Logaraj
DOI:10.1016/s0040-4020(01)86206-2
日期:1988.1
conditions. The E enol was prepared by the enolization reaction of Kohler's ketone (4) with methylmagnesium iodide followed by hydrolysis. The E enol appeared at a retention time of 3.6 compared with that of the Z enol at 4.1 on the HPLC chromatograms. The relative rates of oxidation of the enols as determined by following the disappearance the respective HPLC peaks were approximately 7:1 for Z:E respectively
Stereoselective synthesis of enones from the reaction of aldehydes with sterically hindered dimethylaluminum enolates
作者:Zachary S. Sales、Roger Nassar、J. Jacob Morris、Kenneth W. Henderson
DOI:10.1016/j.jorganchem.2005.04.040
日期:2005.7
to reflux for several hours gave enone products in generally high conversions. The presumed aluminum aldolate intermediates were not detected by in situ monitoring studies and are presumably short-lived under the reaction conditions. The enone products from the addition reactions were formed predominantly as the E-isomers with good to excellent stereoselectivities.
Me 3 Al与甲基酮(2,4,6-R 3 -C 6 H 2)C(O)CH 3之间的等摩尔反应,其中R = Me或i Pr,导致烯醇化产物的排他性形成[ Me 2 AlOC(2,4,6-R 3 –C 6 H 2)CH 2 } 2 ],1和2,在甲苯溶液中加热至回流温度后。在这些反应中,Me 3 Al充当碱而不是亲核试剂的特性是由于酮的位阻特性。2的晶体学分析揭示了一种二聚体复合物,其中金属中心被烯醇化物阴离子桥接,与先前的研究1一致。向1和2的己烷溶液中添加一系列醛,然后加热回流数小时,得到的烯酮产物通常具有很高的转化率。推定铝醛酸酯中间体未通过原位监测研究检测到,并且在反应条件下可能是短命的。来自加成反应的烯酮产物主要形成为具有良好至优异的立体选择性的E-异构体。