54929-04-3Relevant academic research and scientific papers
Dynamic Reductive Kinetic Resolution of Benzyl Ketones using Alcohol Dehydrogenases and Anion Exchange Resins
Méndez-Sánchez, Daniel,Mangas-Sánchez, Juan,Busto, Eduardo,Gotor, Vicente,Gotor-Fernández, Vicente
, p. 122 - 131 (2016/01/25)
Dynamic reductive kinetic resolutions of racemic 3-arylalkanones have been performed by the proper combination of an alcohol dehydrogenase and a basic anionic resin. The best results were found for the bioreduction with the alcohol dehydrogenase type A from Rhodococcus ruber DSM 44541 overexpressed in Escherichia coli (E. coli/ADH-A) and the commercially available evo-1.1.200, while the Amberlite IRA-440 C and the DOWEX-MWA-1 resins allowed efficient in situ racemizations. Reaction conditions were optimized in terms of enzyme source and loading, type and amount of resin, pH, temperature and reaction times, obtaining a series of (R,R)-substituted propan-2-ols with good conversions and both diastereoselectivity and stereoselectivity. As a proof of concept, the subsequent intramolecular cyclization of a selected propan-2-ol substrate afforded a valuable isochroman heterocycle without any loss of the optical purity.
Syntheses of functionalized allylamines via lithiated intermediates
Firdous, Samia,Kazmaier, Uli
, p. 3182 - 3187 (2014/06/09)
Lithiated allylamines are easily available by tin-lithium exchange from stannylated allylamines and are suitable nucleophiles for a wide range of conversions. With aldehydes and ketones, aminomethylated allyl alcohols are formed, whereas the reaction with α-brominated ketones gives rise to vinyl epoxides or aldehydes, depending on the reaction and workup conditions used. Copyright
Addressing challenges in palladium-catalyzed cross-couplings of aryl mesylates: Monoarylation of ketones and primary alkyl amines
Alsabeh, Pamela G.,Stradiotto, Mark
supporting information, p. 7242 - 7246 (2013/07/26)
Mor(DalPhos) for Me(sylates): Described are the first examples of ketone mono-α-arylation and primary aliphatic amine monoarylation employing aryl methanesulfonate coupling partners. A range of functionalized aryl mesylates were employed with dialkyl ketones, and also with primary and secondary amines as well as the otherwise challenging coupling partners acetone and methylamine. Ad=adamantyl. Copyright
Baeyer-Villiger monooxygenase-catalyzed kinetic resolution of racemic α-alkyl benzyl ketones: enzymatic synthesis of α-alkyl benzylketones and α-alkyl benzylesters
Rodriguez, Cristina,Gonzalo, Gonzalo de,Torres Pazmino, Daniel E.,Fraaije, Marco W.,Gotor, Vicente
experimental part, p. 1168 - 1173 (2009/10/02)
The application of three BVMOs for the enantioselective oxidation of 3-phenylbutan-2-ones with different substituents in the aromatic moiety is described. By choosing the appropriate biocatalyst and substrate combination, chiral ketones and esters can be obtained with excellent enantiopurities. This methodology could also be applied to the resolution of racemic α-alkyl benzylketones with longer alkyl chains as well as with two substituted α-substituted benzylacetones. A kinetic analysis revealed that the BVMOs studied effectively convert all tested compounds showing that the enzymes are tolerant towards the substrate structure while being highly enantioselective. These properties render BVMOs as valuable biocatalysts for the preparation of compounds with high interest in organic synthesis.
Application of A Recyclable Pseudoephedrine Resin in Asymmetric Alkylations on Solid Phase
Hutchison, Panee C.,Heightman, Tom D.,Procter, David J.
, p. 790 - 801 (2007/10/03)
A pseudoephedrine resin has been successfully employed in asymmetric alkylations on solid phase. Immobilized pseudoephedrine amides are conveniently prepared by the one-step attachment of pseudoephedrine to Merrifield resin through the hydroxyl group and subsequent acylation on nitrogen. Deprotonation and alkylation of the resin-bound amides proceeds smoothly. Ketones and alcohols are cleaved from the resin in high enantiomeric excess and moderate to good overall yield. The parallel, asymmetric solid-phase synthesis of a small library of chiral ketones and alcohols has been carried out to illustrate the utility of the approach. Finally, the pseudoephedrine resin can be conveniently recycled and utilized with no significant loss in the yield or enantiomeric excess of the products.
Evaluation of a Pseudoephedrine Linker for Asymmetric Alkylations on Solid Phase
Hutchison, Panee C.,Heightman, Tom D.,Procter, David J.
, p. 4583 - 4585 (2007/10/03)
(Equation Presented) Immobilized pseudoephedrine amides have been conveniently prepared by attachment of pseudoephedrine to Merrifield resin and acylation on nitrogen. Deprotonation and alkylation of the resin bound amides proceeds smoothly. Products were cleaved from the resin to give ketones and alcohols in high enantiomeric excess and moderate to good overall yield.
Synthesis and utility of α,α'-bis (triethyl ammonium methylene chloride) β-phenyl ethene in hydroxide ion initiated reactions - A new multi-site phase transfer catalyst
Balakrishnan,Jayachandran
, p. 3821 - 3830 (2007/10/03)
A three step synthesis of novel 'multi-site' water soluble phase transfer catalyst viz, α,α'-bis(triethyl ammonium methylene chloride) β-phenyl ethene and its utility in various organic biphase reactions are described.
CYCLOPHOSPHAZENIC POLYPODANDS AS POWERFUL CATION COMPLEXING AGENTS, EFFICIENT PHASE-TRANSFER CATALYSTS AND ANION ACTIVATORS
Landini, Dario,Maia, Angelamaria,Podda, Gianni
, p. 583 - 588 (2007/10/03)
A survey dealing with cyclophosphazenic polypodands 3a-c, a new class of "octopus-like" molecules is reported.These many-armed ligands are powerful complexing agents of alkali metal salts and hence behave as very efficient catalysts in many reations (nucleophilic substitutions, eliminations, alkylations, oxidations, reductions) under solid-liquid and liquid-liquid phase-transfer catalysis conditions.Their catalytic activity is much better than that of the open-chain analogues PEGs 4, 5 and TRIDENT-1, 6.Moreover, anion activation realized by cyclophosphazenic polypodands, both of homogeneous and heterogeneous systems, is comparable with that obtained with the more sophisticated and expensive crown ethers.
SYNTHESIS OF NEW CYCLOPHOSPHAZENIC POLYPODANDS WITH N,N-BISAMINE SUBUNITS AND THEIR COMPARISON, AS PHASE-TRANSFER CATALYSTS, WITH OTHER PODANDS
Corda, Luciana,Delogu, Giovanna,Maccioni, Antonio,Maccioni, Elias,Podda, Gianni
, p. 491 - 496 (2007/10/02)
Substituted cyclophosphazenes have been prepared by treatment of hexachlorocyclophosphazene with N,N-bisamines and employed as phase-transfer catalysts in anion-promoted reactions.New tridents have also been prepared.
Solid-Liquid Phase-Transfer Catalysis without Solvent: Selective Mono- and Di-alkylation of Benzyl Methyl Ketone
Aranda, Alfonso,Diaz, Angel,Diez-Barra, Enrique,Hoz, Antonio de la,Moreno, Andres,Sanchez-Verdu, Prado
, p. 2427 - 2430 (2007/10/02)
The alkylation of benzyl methyl ketone 1 has been performed by phase-transfer catalysis without solvent.Excellent yields of mono- 2 and di-alkyl derivatives 3 and 4 were obtained through general, selective and mild conditions.
