Trihaloisocyanuric Acid/Triphenylphosphine: An Efficient System for Regioselective Conversion of Epoxides into Vicinal Halohydrins and Vicinal Dihalides under Mild Conditions
作者:Marcio de Mattos、Vitor de Andrade
DOI:10.1055/s-0035-1560408
日期:——
vicinal chloro-/bromohydrins and vicinal dihalides by reaction with the system trihaloisocyanuric acid/triphenylphosphine in acetonitrile under mild and neutral conditions. The reactions proceed smoothly in high yield at room temperature and at reflux, respectively, over a short time. A new synthetic method has been developed for the regioselective conversion of epoxides to vicinal chloro-/bromohydrins
Chlorinated iminium chlorides have been identified to promote the highly efficient and selective mono-chlorination of unsymmetrical vicinal diols. Vilsmeier reagent, namely, (chloromethylene)dimethyliminium chloride, enables highly reactive and regioselective chlorination of 1,2- and 1,3-diols featured one secondary benzylic hydroxy group and one primary aliphatic hydroxy group to give the corresponding
Catalytic, Asymmetric α-Chlorination of Acid Halides
作者:Stefan France、Harald Wack、Andrew E. Taggi、Ahmed M. Hafez、Ty R. Wagerle、Meha H. Shah、Crystal L. Dusich、Thomas Lectka
DOI:10.1021/ja039046t
日期:2004.4.1
process that produces highly optically enriched α-chloroesters from inexpensive, commercially available acidhalides using cinchona alkaloid derivatives as catalysts and polychlorinated quinones as halogenating agents. We have performed kinetics and control experiments to investigate the reaction mechanism and establish conditions under which the reactions can be best performed. We have developed NaH and
我们全面介绍了串联催化、不对称氯化/酯化过程,该过程使用金鸡纳生物碱衍生物作为催化剂和多氯醌作为卤化剂,从廉价的市售酰卤中生产高度光学富集的 α-氯酯。我们已经进行了动力学和控制实验,以研究反应机理并建立可以最好地进行反应的条件。我们开发了 NaH 和 NaHCO3 穿梭基系统作为进行反应的最简单和最具成本效益的方法,使该方法与已知的手性卤化程序在经济上具有竞争力。我们还通过将产品转化为合成有用的衍生物来证明我们的反应的效用。
Organocatalytic asymmetric fluorination of α-chloroaldehydes involving kinetic resolution
of the starting aldehydes was involved in this asymmetricfluorination. This paper describes the determination of the absolute stereochemistry of a resulting alpha-chloro-alpha-fluoroaldehyde. Some information about the substrate scope and a possible reaction mechanism are also described which shed more light on the nature of this asymmetricfluorination reaction.
Highly Regio- and Stereoselective Synthesis of β-Halohydrins from Epoxides Catalyzed with Ceric Ammonium Nitrate
作者:N. Iranpoor、F. Kazemi、P. Salehi
DOI:10.1080/00397919708003362
日期:1997.4
ceric ammonium nitrate can effectively catalyze ring opening of epoxides with halides under very mild conditions and easy procedure to give the corresponding β-chloro-and β-bromohydrins in excellent yields. The reactions occur with both substituted and unsubstituted quaternary ammonium halides and with high regio- and stereoselectivity. The reaction of opticallyactive styrene oxide with chloride ion was
摘要 Ce(IV)作为硝酸铈铵可以在非常温和的条件和简单的程序下有效地催化环氧化物与卤化物的开环,以优异的收率得到相应的β-氯代醇和β-溴代醇。该反应同时发生在取代和未取代的季铵卤化物中,并且具有高区域选择性和立体选择性。发现光学活性氧化苯乙烯与氯离子的反应具有高度立体定向性,并以 96% ee 提供相应的 β-卤代醇。