used as an aza-Michael donor in organocatalyticasymmetricreactions with symmetric and nonsymmetric unsaturated 1,4-diketones. After hydrolysis (in situ), the N-substituted isatins were obtained in high yields (up to >95%) with high enantioselectivity (up to 95%). Isatin was activated by derivatization to a Schiff base with aniline and used as an aza-Michael donor in organocatalyticasymmetric reactions
Catalyst-Controlled, Enantioselective, and Diastereodivergent Conjugate Addition of Aldehydes to Electron-Deficient Olefins
作者:S. B. Jennifer Kan、Hiroki Maruyama、Matsujiro Akakura、Taichi Kano、Keiji Maruoka
DOI:10.1002/anie.201705546
日期:2017.8.1
A chiral-amine-catalyzed enantioselective and diastereodivergent method for aldehyde addition to electron-deficient olefins is presented. Hydrogen bonding was used as a control element to achieve unusual anti selectivity, which was further elucidated through mechanistic and computational studies.
sulfinamide bisphosphine catalysts (Wei‐Phos) were developed. These could be easily prepared from commercially available starting materials. Wei‐Phos has shown good performance in the very challenging intermolecular cross‐Rauhut–Currier reactions of vinyl ketones and 3‐acyl acrylates or 2‐ene‐1,4‐diones, leading to the R‐C products in high yields with up to 99 % ee under 2.5–5 mol% catalyst loading. The highly
Umsetzungen mit Nitroenaminen, XI. Synthese von gesättigten und ungesättigten 1,4‐Dicarbonyl‐verbindungen
作者:Theodor Severin、Dieter König
DOI:10.1002/cber.19741070510
日期:1974.5
Ketone mit α-ständiger Methyl- oder Methylengruppe lassen sich mit 1-Dimethylamino-2-nitro-1-propen in Gegenwart von Basen zu aci-Nitropropyliden-Derivaten umsetzen (5 + 6 7). Diese aci-Nitro-Ketone werden auf Kieselgel in die entsprechenden 1,4-Dicarbonylverbindungen 9 umgewandelt. Andere Methoden zur Darstellung von 9 aus 7 wie Oxidation mit Peroxodisulfat oder Reduktion mit Ascorbinsäure bringen