116140-68-2Relevant academic research and scientific papers
Large-scale green chemical synthesis of adjacent quaternary chiral centers by continuous flow photodecarbonylation of aqueous suspensions of nanocrystalline ketones
Hernndez-Linares, Mara Guadalupe,Guerrero-Luna, Gabriel,Prez-Estrada, Salvador,Ellison, Martha,Ortin, Maria-Mar,Garcia-Garibay, Miguel A.
, p. 1679 - 1684 (2015)
To demonstrate the ease of scale-up and synthetic potential of some organic solid state reactions, we report the synthesis, crystallization, and solid state photochemistry of acyclic, homochiral, hexasubstituted (+)-(2R,4S)-2-carbomethoxy-4-cyano-2,4-diph
Rhodium-Catalyzed Hydrocarboxylation of Olefins with Carbon Dioxide
Kawashima, Shingo,Aikawa, Kohsuke,Mikami, Koichi
, p. 3166 - 3170 (2016/07/19)
The catalytic hydrocarboxylation of styrenes derivatives and α,β-unsaturated carbonyl compounds with CO2(101.3 kPa) in the presence of an air-stable rhodium catalyst was explored. The combination of [RhCl(cod)]2(cod = cyclooctadiene) as a catalyst and diethylzinc as a hydride source allowed for effective hydrocarboxylation and provided the corresponding α-aryl carboxylic acids in moderate to excellent yields. In this catalytic process with carbon dioxide, intervention of the RhI–H species, which could be generated from the RhIcatalyst and diethylzinc, was clarified. Significantly, the catalytic asymmetric hydrocarboxylation of α,β-unsaturated esters with carbon dioxide was also performed by employing a cationic rhodium complex possessing (S)-(–)-4,4′-bi-1,3-benzodioxole-5,5′-diylbis(diphenylphosphine) [(S)-SEGPHOS] as a chiral diphosphine ligand. A plausible model for asymmetric induction was proposed by determination of the absolute configuration of the product.
The synthesis and stereospecific solid-state photodecarbonylation of hexasubstituted meso- and d,l-ketones
Shiraki, Saori,Natarajan, Arunkumar,Garcia-Garibay, Miguel A.
, p. 1480 - 1487 (2012/06/01)
Tertiary carbanions were trapped with half an equivalent of diphosgene to give meso- and d,l-hexasubstituted ketones in moderate yields and modest diastereoselectivities. The ketones were also synthesized by a step-wise synthesis in which the carbonyl group was first installed as an acid before activation and the second nucleophilic attack. This second method gave lower yields but similar diastereoselectivites. Steric limits of both methods were also determined. The photolysis of the resulting crystalline ketones gave a mixture of products in solution, but took place chemoselectively and diastereospecifically in the solid-state. The Royal Society of Chemistry and Owner Societies.
Enantioselective synthesis of a-quaternary amino acid derivatives by sequential enzymatic desymmetrization and curtius rearrangement of α,α-disubstituted malonate diesters
Iosub, Violeta,Haberl, Anton R.,Leung, Jennifer,Tang, Michael,Vembaiyan, Kannan,Parvez, Masood,Back, Thomas G.
experimental part, p. 1612 - 1619 (2010/04/29)
(Figure Presented) A convenient and versatile enantioselective synthesis of biologically important α-quatemary amino acid derivatives was based on the sequential double alkylation or arylation of dimethyl malonate, followed by desymmetrization with porcine liver esterase (PLE) and Curtius rearrangement. The PLE-mediated hydrolysis of the prochiral dialkylated malonate diesters produced the corresponding chiral half-esters in high yield and with enantiomeric excesses of 43% to >98%. Curtius rearrangement of the latter products, after trapping of the intermediate isocyanates with benzyl alcohol or amines, afforded the corresponding Cbz-protected amino esters or ureas. The absolute configurations of the major products in five examples were established by conversion to compounds with known specific rotations, or by X-ray crystallography of derivatives obtained with chiral amines of known configuration.
Enantiospecific synthesis of vicinal stereogenic tertiary and quaternary centers by combination of configurationally-trapped radical pairs in crystalline solids
Ellison, Martha E.,Ng, Danny,Dang, Hung,Garcia-Garibay, Miguel A.
, p. 2531 - 2534 (2007/10/03)
(Matrix presented) Photochemical irradiation of crystalline (2R,4S)-2-carbomethoxy-4-cyano-2,4-diphenyl-3-butanone 1 led to highly efficient decarbonylation reactions. Experiments with optically pure and racemic crystals showed that the intermediate radic
Enzymes in organic synthesis 50. Probing the dimensions of the large hydrophobic binding region of the active site of pig liver esterase using substituted aryl malonate substrates
Toone,Jones
, p. 1041 - 1052 (2007/10/02)
The active side model reported recently for the synthetically useful enzyme pig liver esterase (PLE) permits the structural specificity and stereoselectivity of the enzyme to be interpreted and predicted for a wide range of substrates. The specifications
