1,5-Dicarbonyl-Verbindungen durch Michael-Addition deprotonierter Enamine und Allylamine an 2-(<i>N</i>-Methylanilino)-acrylnitril
作者:Hubertus Ahlbrecht、Manfred Dietz、Lothar Weber
DOI:10.1055/s-1987-27904
日期:——
1,5-Dicarbonyl Compounds via Michael-Addition of Deprotonated Enamines and Allylamines to 2-(N-Methylanilino) acrylonitrile A new method for the synthesis of the title compounds by a onepot, three component, coupling reaction is described. Is consists of the reaction of a homoenolate anion and an enol cation equivalent with subsequent alkylation of an acyl-anion equivalent. Hence the methodology of Umpolung is used in a threefold manner within the reaction sequence.
Cooperative Catalysis of Samarium Diiodide and Mercaptan in a Stereoselective One-Pot Transformation of 5-Oxopentanals into δ-Lactones
作者:Jue-Liang Hsu、Chao-Tsen Chen、Jim-Min Fang
DOI:10.1021/ol9911526
日期:1999.12.1
[GRAPHICS]We demonstrate a general method for conversion of various 5-oxopentanals to substituted delta-lactones and 1-oxa-2-decalones by the synergistic catalysis of samarium diiodide and 2-propanethiol (or disulfide), The deliberate use of mercaptan is advantageous to facilitate the catalytic cycle, This method shows high stereoselectivities, and an enantioselective procedure is feasible by using the chiral mercaptan (1R,2S)-1 phenyl-2-(N-acetamido)propanethiol as a promoter.
AHLBRECHT H.; DIETZ M.; WEBER L., SYNTHESIS,(1987) N 3, 251-254
作者:AHLBRECHT H.、 DIETZ M.、 WEBER L.
DOI:——
日期:——
Stereoselective Synthesis of δ-Lactones from 5-Oxoalkanals via One-Pot Sequential Acetalization, Tishchenko Reaction, and Lactonization by Cooperative Catalysis of Samarium Ion and Mercaptan
作者:Jue-Liang Hsu、Jim-Min Fang
DOI:10.1021/jo016058t
日期:2001.12.1
sequence of acetalization, Tishchenko reaction and lactonization. The deliberative use of mercaptan, by comparison with alcohol, is advantageous to facilitate the catalytic cycle. The reaction mechanism and stereochemistry are proposed and supported by some experimental evidence. Such samarium ion/mercaptan cocatalyzed reactions show the feature of remote control, which is applicable to the asymmetric synthesis