42432-27-9Relevant academic research and scientific papers
Facile synthesis of libraries of functionalized cyclopropanes and oxiranes using ionic liquids – A new approach to the classical Corey-Chaykovsky reaction
Malunavar, Shruti S.,Sutar, Suraj M.,Prabhala, Pavankumar,Savanur, Hemantkumar M.,Kalkhambkar, Rajesh G.,Aridoss, Gopalakrishnan,Laali, Kenneth K.
supporting information, (2021/09/13)
The potential of [PAIM][NTf2]/BMIM-ILs as a base/solvent in the Corey-Chaykovsky reaction is demonstrated by the facile synthesis of libraries of functionalized cyclopropanes from enones and oxiranes from aldehydes and ketones, at room temperature in respectable isolated yields. To demonstrate their application, the synthesized epoxides were employed as substrates for the synthesis of a library of 2,3-disubstituted quinolines, using [BMIM(SO3H)][OTf]/[BMIM][PF6] as a catalyst/solvent. The potential for recycling/reuse of the IL solvents was also explored.
Continuous Flow Synthesis of Terminal Epoxides from Ketones Using in Situ Generated Bromomethyl Lithium
Von Keutz, Timo,Cantillo, David,Kappe, C. Oliver
supporting information, p. 10094 - 10098 (2019/12/24)
A scalable procedure for the direct preparation of epoxides from ketones has been developed. The method is based on the carefully controlled generation of (bromomethyl)lithium (LiCH2Br) from inexpensive CH2Br2 and MeLi in a continuous flow reactor. The reaction has shown excellent selectivity for a variety of substrates, including α-chloroketones, which typically fail under classic Corey-Chaykovsky conditions. This advantage has been used to develop a novel route toward the drug fluconazole.
Mild Iridium-Catalysed Isomerization of Epoxides. Computational Insights and Application to the Synthesis of β-Alkyl Amines
Cabré, Albert,Cabezas-Giménez, Juanjo,Sciortino, Giuseppe,Ujaque, Gregori,Verdaguer, Xavier,Lledós, Agustí,Riera, Antoni
supporting information, p. 3624 - 3631 (2019/07/10)
The isomerization of epoxides to aldehydes using the readily available Crabtree's reagent is described. The aldehydes were transformed into synthetically useful amines by a one-pot reductive amination using pyrrolidine as imine-formation catalyst. The reactions worked with low catalyst loadings in very mild conditions. The procedure is operationally simple and tolerates a wide range of functional groups. A DFT study of its mechanism is presented showing that the isomerization takes place via an iridium hydride mechanism with a low energy barrier, in agreement with the mild reaction conditions. (Figure presented.).
Spectroscopy and catalytic activity study of gold supported on barium titanate nanotubes for styrene epoxidation
Nepak, Devadutta,Srinivas, Darbha
, p. 61 - 72 (2016/06/13)
Gold (0.5-5 wt.%) supported on barium titanate nanotubes (Au/BaTNT) were prepared, characterized and for the first time, investigated as catalysts for selective oxidation of styrene with oxygen (O2 or H2 + O2) and peroxides (H2O2 or TBHP). Conversion of styrene enhanced when H2 was co-added to O2 in the reactions. Au/BaTNT activated O2 and H2 and produced H2O2 in situ for use in oxidations. Peroxides were found better oxidants than O2. At optimized conditions, styrene oxide selectivity of 80.1 wt.% at styrene conversion of 60.5 wt.% was achieved over Au(1 wt.%)/BaTNT using TBHP. Au particles (5.0-7.4 nm) were dispersed and decorated on the walls of BaTNT. They exhibited superior performance to the known Au catalysts in styrene oxidation. Reactive oxygen species formed during oxidation reactions were followed with in situ spectral characterizations (diffuse reflectance UV-vis and FT-Raman). Au/BaTNT was reusable in four recycles with little loss in catalytic activity.
β-tert-Butyl aspartate as an organocatalyst for the asymmetric α-amination of α,α-disubstituted aldehydes
Theodorou, Alexis,Papadopoulos, Giorgos N.,Kokotos, Christoforos G.
supporting information, p. 5438 - 5443 (2013/07/05)
The enantioselective α-amination reaction of α,α- disubstituted aldehydes can lead to a variety of enantioenriched amino aldehydes, amino alcohols, and amino acids. After screening a variety of amino acids and their derivatives, we identified a cheap, simple, commercially available aspartic acid derivative that can catalyze efficiently the reaction between α,α-disubstituted aldehydes and dialkyl azodicarboxylates. The reaction proceeds smoothly leading to the corresponding α-aminated adducts in moderate to quantitative yields and moderate to high enantioselectivities (up to 96% ee). Finally, the conversion of these adducts to α,α-disubstituted quaternary amino acids is also described.
Generation and reactions of oxiranyllithiums by use of a flow microreactor system
Nagaki, Aiichiro,Takizawa, Eiji,Yoshida, Jun-Ichi
supporting information; experimental part, p. 14149 - 14158 (2011/02/25)
A flow microreactor system consisting of micromixers and microtubes provides an effective reactor for the generation and reactions of aryloxiranyllithiums without decomposition by virtue of short residence time and efficient temperature control. The depro
Efficient catalytic Corey-Chaykovsky reactions involving ketone substrates
Kavanagh, Sarah A.,Piccinini, Alessandro,Connon, Stephen J.
supporting information; experimental part, p. 2089 - 2093 (2010/11/04)
It has been demonstrated for the first time that a sulfide catalyst, utilised at 20 mol% loading, can promote methylene transfer to ketones in the presence of methyl triflate and an organic base. This metal-free methodology is of broad scope-both aliphatic and aromatic ketones (including trifluoromethyl ketones) can be converted to synthetically useful terminal epoxides in excellent yields at room temperature.
"Instant methylide" modification of the Corey-Chaykovsky epoxide synthesis
Ciaccio, James A.,Drahus, Antoinette L.,Meis, Regina M.,Tingle, Carice T.,Smrtka, Michael,Geneste, Richard
, p. 2135 - 2143 (2007/10/03)
We report that Me3S(O)+I- (1) and Me3S+I- (2) form stable, dry mixtures with KOt-Bu and NaH, respectively, which remain stable upon prolonged storage (> 1 year). The corresponding methylides (Me2SO=CH2 and Me2S=CH2) are generated upon addition of DMSO or DMSO/THF solutions of carbonyl compounds, cleanly affording epoxides via the Corey-Chaykovsky reaction in good yields and short reaction times (as short as 20 min when 1-2 mmol of various ketones and aldehydes were treated with a mixture of 1 and KOt-Bu at 50-60°C).
Enantioselective hydrolysis of 2,2-disubstituted oxiranes mediated by microsomal epoxide hydrolase
Basavaiah,Bhaskar Raju
, p. 3293 - 3306 (2007/10/03)
2-Aryl-2-methyloxiranes are enantioselectively hydrolyzed with microsomal epoxide hydrolase from pig liver to provide 1,2-diols containing a tertiary benzylic alcohol stereogenic centre upto 34% enantiomeric purities.
Lipase-catalyzed hydrolysis of some racemic 1-acetoxy-2-arylpropanes
Matsumoto,Takeda,Iwata,Sakamoto,Ishida
, p. 1191 - 1197 (2007/10/02)
Racemic 1-acetoxy-2-phenylpropane (12) and 1-acetoxy-2-(2- naphthyl)propane (33) were hydrolyzed with lipase at 35-36°C for 2 and 24 h to give predominantly (S)-2-phenyl-1-propanol (11) and (S)-2-(2-naphthyl)-1- propanol (32), respectively. However, racemic 1-acetoxy-2-(1-naphthyl)propane (25) was recovered intact even when the reaction was carried out for 240 h. On the other hand, the enantioselectivities towards racemic 2-phenyl (16), 2- (p-tolyl) (20), 2-(1-naphthyl) (28), and 2-(2-naphthyl) (36) derivatives of 1-acetoxy-2-propanol were very low.
