关键词： 三氟甲基磺酸铜   不对称合成   手性催化剂   手性双噁唑啉   手性亚磷酸胺酯   手性亚磷酸酚酯  

摘要： 三氟甲基磺酸铜 [Cu(OTf) 2 ]与各种手性磷氮配体络合催化不对称合成已取得了巨大进展 .

关键词： 潜手性Schiff碱   不对称合成   催化氢化反应   均相反应   非均相反应   氢转移  

摘要： 对近年来潜手性Schiff碱的不对称催化氢化的发展状况按照均相。

关键词： asymmetric synthesis   Mannich reaction   organic catalysis   oxidation   proline  

摘要： trans-4-tert-Butyldimethylsiloxy-L-proline displays a greater catalytic activity than the parent proline without compromising the enantioselectivity, which widens the substrate scope in the alpha-aminoxylation of carbonyl compounds, as well as O-nitrosoaldol/Michael, and Mannich reactions.

关键词： Additives   Organic synthesis   Selectivity   Nitrogen compounds   Stereoselectivity  

摘要： Highly diastereoselective intra- and intermolecular self-condensation reactions of N-tert-butanesulfinyl aldimines have been developed and applied to the rapid, asymmetric synthesis of trans-2-aminocyclopentanecarboxylic acid and the drug candidate SC-53116. Key to both syntheses is a novel microwave-assisted reaction in which N-sulfinyl aldimines are cleanly converted into nitriles in high-yielding concerted elimination processes.

关键词： Catalysts   Chemical reactions   Reaction products   Desymmetrization   Stereoselectivity  

摘要： N-Monoallylation of meso-vicinal diamine bistrisylamides using a chiral pi-allyl-Pd catalyst proceeded in an enantioselective manner (up to 90% ee) to give desymmetrization products in good yields. The product was converted to the known or-receptor agonist in short steps. In addition, the present catalytic asymmetric N-allylation was applied to kinetic resolution of racemic-diamide.

关键词： PHASE-TRANSFER CATALYSTS   CARBACEPHEM ANTIBIOTIC LORACARBEF   DYNAMIC KINETICRESOLUTION   ENANTIOSELECTIVE SYNTHESIS   SCHIFF-BASE   STEREOSELECTIVE-SYNTHESIS   ENZYMATIC-SYNTHESIS   EFFICIENT APPROACH   ALDEHYDES   DERIVATIVES  

摘要： The Cinchona alkaloid derived chiral ammonium salt developed by Park and Jew functions as an effective catalyst for the synthesis of beta-hydroxy alpha-amino acids via asymmetric aldol reactions under homogeneous conditions. The syn diastereomers are obtained in good ee, and aryl-substituted aliphatic aldehydes are the best substrates for the reaction. These results represent the highest ee's obtained to date in direct aldol reactions of glycine equivalents catalyzed by inexpensive, readily prepared chiral ammonium salts.

关键词： Reagents   Peptides and proteins   Monomers   Ketones   Enantioselective synthesis  

摘要： N-Sulfinyl alpha-amino 1,3-dithioketals are prepared in high de and good yield by treating sulfinimines with lithio-1,3-dithianes. Selective removal of the N-sulfinyl or the thioketal groups affords stable a-amino 1,3-dithioketals and N-sulfinyl alpha-amino ketones, respectively. This new sulfinimine-derived chiral building block is employed in the asymmetric synthesis of polyoxypeptin amino acid (2S,3R)-(-)-3-hydroxy-3-methylproline.

关键词： Transition states   Stereoselectivity   Mixtures   Ethers   Molecular structure  

摘要： An asymmetric synthesis of the 3,5-dihydroxycyclohexanone subunit of baconipyrones A and B, as well as that of the hydroxydiketone subunit of baconipyrones C and D ((-)-(4S,6S)-4,6-dimethyl-5-hydroxynonan-3,7-dione), is described. Key steps include sulfur dioxide-induced additions of enoxysilanes to 1,3-dioxy-1,3-dienes, followed by retro-ene desulfitations (retro-ene elimination of SO2).

关键词： Hydrocarbons   High-performance liquid chromatography   Ligands   Aromatic compounds   Hydrogenation  

摘要： A facile preparation of chiral alpha-aryloxy carboxylic acids via asymmetric hydrogenation of the corresponding unsaturated acids has been discovered. A number of catalysts have been identified that give high product enantioselectivity, and the scope of the reaction has been examined with respect to substitution on the aromatic ring and olefin.

关键词： Anions   Reaction products   Stereoselectivity   Molecular structure   Allylation  

摘要： A concise method to asymmetrically synthesize 6-hydroxy-3,8-dioxabicyclo[3.2.1]octane (HDBO) derivatives was devised.