111183-88-1Relevant academic research and scientific papers
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
Hsu,Fang
, p. 8573 - 8584 (2007/10/03)
By the synergistic catalysis of samarium ion and mercaptan, a series of 5-oxoalkanals was converted to (substituted) δ-lactones in efficient and stereoselective manners. This one-pot procedure comprises a 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 of optically active δ-lactones. This study also demonstrates the synthesis of two insect pheromones, (2S,5R)-2-methylhexanolide and (R)-hexadecanolide, as examples of a new protocol for asymmetric reduction of long-chain aliphatic ketones.
1,5-Dicarbonyl Compounds via Michael-Addition of Deprotonated Enamines and Allylamines to 2-(N-Methylanilino) acrylonitrile
Ahlbrecht, Hubertus,Dietz, Manfred,Weber, Lothar
, p. 251 - 254 (2007/10/02)
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.
