Rhodium-Catalyzed Hydrocarboxylation of Olefins with Carbon Dioxide
作者:Shingo Kawashima、Kohsuke Aikawa、Koichi Mikami
DOI:10.1002/ejoc.201600338
日期:2016.7
excellent yields. In this catalytic process with carbon dioxide, intervention of the RhI–H species, which could be generated from the RhI catalyst and diethylzinc, was clarified. Significantly, the catalyticasymmetric 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)
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
作者:Eric J. Toone、J.Bryan Jones
DOI:10.1016/s0957-4166(00)86155-8
日期:1991.1
The active site model reported recently for the synthetically useful enzymepigliveresterase (PILE) permits the structural specificity and stereoselectivity of the enzyme to be interpreted and predicted for a wide range of substrates. The specifications of the dimensions of this model were based on the specificity data available at that time. In order to test the model further, and to delineate more
Enantiospecific Synthesis of Vicinal Stereogenic Tertiary and Quaternary Centers by Combination of Configurationally-Trapped Radical Pairs in Crystalline Solids
作者:Martha E. Ellison、Danny Ng、Hung Dang、Miguel A. Garcia-Garibay
DOI:10.1021/ol0347803
日期:2003.7.1
[GRAPHIC]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 radical pairs undergo a highly diastereo- and enantiospecific radical-radical combination that leads to the formation of two adjacent stereogenic centers in good chemical yield and with high chemical control. Reactions with chiral crystals occurred with quantitative enantiomeric yields and >95% diastereomeric yields.
Large-Scale Green Chemical Synthesis of Adjacent Quaternary Chiral Centers by Continuous Flow Photodecarbonylation of Aqueous Suspensions of Nanocrystalline Ketones
作者:María Guadalupe Hernández-Linares、Gabriel Guerrero-Luna、Salvador Pérez-Estrada、Martha Ellison、Maria-Mar Ortin、Miguel A. Garcia-Garibay
DOI:10.1021/ja512524j
日期:2015.2.4
4-diphenyl-3-pentanone 1. We demonstrate that solid state photodecarbonylation of (+)-(2R,4S)-1 affords (+)-(2R,3R)-2-carbomethoxy-3-cyano-2,3-diphenyl-butane 2 with two adjacent stereogenic, all-carbon substituted quaternary centers, in quantitative chemical yield and 100% diastereoselectivity and enantiomeric excess. The efficient multigram photodecarbonylation of (+)-(2R,4S)-1 as a nanocrystalline suspension
Enantioselective Synthesis of α-Quaternary Amino Acid Derivatives by Sequential Enzymatic Desymmetrization and Curtius Rearrangement of α,α-Disubstituted Malonate Diesters
作者:Violeta Iosub、Anton R. Haberl、Jennifer Leung、Michael Tang、Kannan Vembaiyan、Masood Parvez、Thomas G. Back
DOI:10.1021/jo902584r
日期:2010.3.5
A convenient and versatile enantioselective synthesis of biologically important α-quaternary 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