7065-48-7Relevant academic research and scientific papers
Highly Selective Hydrogenation of Aromatic Ketones and Phenols Enabled by Cyclic (Amino)(alkyl)carbene Rhodium Complexes
Wei, Yu,Rao, Bin,Cong, Xuefeng,Zeng, Xiaoming
supporting information, p. 9250 - 9253 (2015/08/11)
Air-stable Rh complexes ligated by strongly σ-donating cyclic (amino)(alkyl)carbenes (CAACs) show unique catalytic activity for the selective hydrogenation of aromatic ketones and phenols by reducing the aryl groups. The use of CAAC ligands is essential for achieving high selectivity and conversion. This method is characterized by its good compatibility with unsaturated ketones, esters, carboxylic acids, amides, and amino acids and is scalable without detriment to its efficiency.
Tetrabutylammonium prolinate-based ionic liquids: A combined asymmetric catalysis, antimicrobial toxicity and biodegradation assessment
Ferlin, Nadege,Courty, Matthieu,Van Nhien, Albert Nguyen,Gatard, Sylvain,Pour, Milan,Quilty, Brid,Ghavre, Mukund,Haiss, Annette,Kuemmerer, Klaus,Gathergood, Nicholas,Bouquillon, Sandrine
, p. 26241 - 26251 (2013/12/04)
Chiral ionic liquids (CILs) tetrabutylammonium-(S)-prolinate, tetrabutylammonium-(R)-prolinate and tetrabutylammonium trans-4-hydroxy-(S)- prolinate were investigated as chiral additives in the Pd-catalyzed enantioselective hydrogenation of α,β-unsaturated ketones. These CILs were easily prepared in one step from the aminoacid and tetrabutylammonium hydroxide and characterized (NMR, IR, optical rotation, elemental analysis, DSC, viscosity, decomposition temperature). The research strategy was to assess the antimicrobial toxicity (>20 strains) and biodegradability (OECD 301D) of the CILs at the same time as undertaking the asymmetric catalysis study. The Pd-catalyzed enantioselective hydrogenation of the carbon-carbon double bond of α,β-unsaturated ketones under mild conditions (room temperature, 1 atm of H2) in different solvents with CILs present. The best results were obtained in i-PrOH after 18 hours of reaction with a i-PrOH/IL ratio of 5. While all three CILs have low antimicrobial toxicity to a wide range of bacteria and fungi, tetrabutylammonium-(S)-prolinate, tetrabutylammonium-(R)-prolinate and tetrabutylammonium trans-4-hydroxy-(S)-prolinate did not pass the Closed Bottle biodegradation test.
Site-saturation mutagenesis of tryptophan 116 of saccharomyces pastorianus old yellow enzyme uncovers stereocomplementary variants
Padhi, Santosh Kumar,Bougioukou, Despina J.,Stewart, Jon D.
experimental part, p. 3271 - 3280 (2009/07/30)
Site-saturation mutagenesis was used to generate all possible replacements for Trp 116 of Saccharomyces pastorianus (formerly Saccharomyces carlsbergensis) old yellow enzyme (OYE). Our original hypothesissthat smaller amino acids at position 116 would allow better acceptance of bulky 3-alkylsubstituted 2-cyclohexenonessproved incorrect. Instead, Phe and Ile replacements favored the binding of some substrates in an opposite orientation, which yielded reversed stereochemical outcomes compared to that of the wild-type OYE. For example, W116I OYE reduced (R)- and (S)-carvone to enantiomeric products, rather than the diastereomers produced by the wild-type OYE. Deuterium labeling revealed that (S)-carvone reduction by the W116I OYE occurred by the same pathway as that by the wild type (net trans-addition of H2), proving that different substrate binding orientations were responsible for the divergent products. Trp 116 mutants also afforded different stereochemical outcomes for reductions of (R)- perillaldehyde and neral. Preliminary studies of an OYE family member whosenative sequence contains Ile at position 116 (Pichia stipitis OYE 2.6) revealed that this enzyme's stereoselectivity matched that of the wild-t ype S. pastorianus OYE, showing that the identity of the residue at position 116 does not solely determine the substrate binding orientation. Computational docking studies using an induced fit methodology successfully reproduced the majority of the experimental outcomes. These computational tools will allow preliminary in silico screening of additional residues to identify those most likely to control the substrate binding orientation and provide some guidance to future experimental studies.
Stereoselective synthesis of (6R)- and (6S)-diosphenol and Ψ-diosphenol
Schneider, David F,Viljoen, Murray S
, p. 5307 - 5315 (2007/10/03)
Methods are discussed for the stereoselective synthesis of the (R)-and (S)-enantiomers of the diosphenols (5)-(8) by utilizing the commercially available stereoisomers (9), (12), (23) and (25) of carvone and limonene, respectively, as chiral starting materials.
Tetra-N-propylammonium perruthenate: A case study in catalyst recovery and re-use involving tetraalkylammonium salts
Ley,Ramarao,Smith
, p. 2278 - 2279 (2007/10/03)
The use of tetraalkylammonium salts or imidazolium ionic liquids in catalytic oxidations of alcohols with tetra-N-propylammonium perruthenate allows recovery and reuse of the oxidant; this concept may find application in the recovery of other homogenous catalysts.
PHOTOCHEMICAL TRANSFORMATIONS-IV. OXYFUNCTIONALIZATION OF SOME SATURATED HYDROCARBONS WITH HYDROXYL RADICALS
Sharma, S. N.,Sonawane, H. R.,Dev, Sukh
, p. 2483 - 2492 (2007/10/02)
It is shown that hydroxylation of saturated hydrocarbons by hydrogen peroxide occurs under the influence of light.This reaction has been investigated on acyclic, monocyclic and bicyclic hydrocarbons.These reactions were also studied using performic acid as the source of hydroxyl radicals and results compared with those obtained with peracetic acid.As expected, the preferred attack was on tertiary centres, followed by secondary and then primary.
HYDROGENOLYSE EN PHASE LIQUIDE SUR Pd/C DES EPOXYDES DU CARVOMENTHENE ET DU LIMONENE
Accrombessi, G.,Geneste, P.,Olive, J.-L.,Pavia, A. A.
, p. 3135 - 3140 (2007/10/02)
Hydrogenolysis over Pd/C of cis and trans epoxides of carvomenthene and limonene give a mixture of hydrocarbons, secondary and tertiary alcohols, and ketones in proportions dependent upon the nature of the starting material.In the limonene epoxides, the extracyclic double bond plays an important role in the opening of the oxirane ring through a common unsaturated tertiary alcohol intermediate by double bond migration, hydrogenation of which leads to the products.For the carvomenthene epoxides the results are similar to those found in the 4-t-butyl series with competition between cis addition and trans addition of hydrogen.The presence of the isopropenyl group leads to slower reaction rates in comparison with t-butyl analogues.
