Micellar media are introduced for the efficient ring opening of epoxides with sodium salts of nucleophiles such as CNâ, N3â, NO3â, NO2â, SCNâ, Brâ and Clâ, catalyzed with Ce(OTf)4. This method is an efficient procedure for the synthesis of different β-substituted alcohols under mild reaction conditions. The reaction with SCNâ is an easy procedure for the high yielding preparation of epoxy sulfides.
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。
FeCl3•6H2O Supported on SiO2 Catalysed Ring Opening of Epoxides with Alcohols, Acetic Acid, Water, Chloride, Bromide and Nitrate Ions
FeCl3•6H2O absorbed on chromatographic silica gel can act as an efficient catalyst for alcoholysis, hydrolysis and acetolysis of epoxides. Methanolysis of (R)-styrene oxide proceeds with high stereospecificity and in excellent yield. This catalyst can also convert epoxides to their corresponding β-halohydrins and β-nitrato alcohols in the presence of chloride, bromide and nitrate ions respectively.
Iron(III) Trifluoroacetate as an Efficient Catalyst for Solvolytic and Nonsolvolytic Nucleophilic Ring Opening of Epoxides
作者:Nasser Iranpoor、Hadi Adibi
DOI:10.1246/bcsj.73.675
日期:2000.3
Iron(III) trifluoroacetate was used as an efficient and nonhygroscopic catalyst for the alcoholysis, hydrolysis, and acetolysis of epoxides. The addition of chloride, bromide, iodide, and nitrate ions to epoxides to produce the corresponding 2-halo and 2-nitratoalkanols and also the conversion of epoxides to acetonides and thiiranes were also performed efficiently in the presence of this catalyst.
Vinyl Ethers Containing an Epoxy Group: XXIII. Reactions of Alkynylmagnesium Bromides with Glycidol Ethers: Synthesis and Thermal Transformations of 1-[2-( Vinyloxy)ethoxy]- and 1-(Allyloxy)-5-hexyn-2-ols, -5-phenyl-4-pentyn-2-ols, and -3-bromo-2-propanols
作者:L. L. Dmitrieva、L. P. Nikitina、A. I. Albanov、N. A. Nedolya
DOI:10.1007/s11178-006-0002-3
日期:2005.11
Reaction of 2-[2-(vinyloxy)ethoxy]methyl- and 2-(allyloxymethyl)oxiranes with 2-propynyl- and phenylethynylmagnesium bromides (10–55°C, 0.5–4 h) resulted in new representatives of the series of 1-organyloxy-5-hexyn-2-ols, -5-phenyl-4-pentyn-2-ols, and -3-bromo-2-propanols in 50–99% yields. During distillation the 1-[2(vinyloxy)ethoxy]-5-phenyl-4-pentyn-2-ol and -3-bromo-2-propanol transform respectively into 2-methyl-4-(3-phenyl-2-propynyl)- and 2-methyl-4-(bromomethyl)-1,3,6-trioxocanes via intramolecular cyclization involving the hydroxy and vinyloxy groups.