Reaction of certain geometrically defined 1,1-dioxy-4-alkyl- and -4,4-dialkyl-substituted buta-1,3-dienes with halogenated quinones does not involve Diels-Alder or Michael addition chemistry. Instead, rapid competitive oxidation of the dienes to give 2,4-dienoate esters was observed. This new reaction involves strong spatial association between diene and quinone, hydrogen being transferred specifically from the (4E)-alkyl group. Its scope is compared with addition of the same terminally substituted dienes towards the reactive non-quinonoid dienophile tetracyanoethylene.
There are disclosed compounds that modulate or inhibit the enzymatic activity of indoleamine 2,3-dioxygenase (IDO), pharmaceutical compositions containing said compounds and methods of treating proliferative disorders, such as cancer, viral infections and/or inflammatory disorders utilizing the compounds of the invention.
Wittig reactions, of stable phosphorous ylids, when carried out in presence of silicagel, in hexane, provide a fast, efficient and simple method to obtain α:β unsaturated compounds in high yields and high purity.
Stereoselective synthesis of α,β-unsaturated esters
作者:Marc Larchevêque、Alain Debal
DOI:10.1039/c39810000877
日期:——
Reaction of α-silylated ester magnesium enolates with aldehydes affords exclusively one diastereoisomer of the two possible β-hydroxy silanes which give pure E-unsaturated esters on acid work-up.
On the Mechanism of the Copper-Catalyzed Enantioselective 1,4-Addition of Grignard Reagents to α,β-Unsaturated Carbonyl Compounds
作者:Syuzanna R. Harutyunyan、Fernando López、Wesley R. Browne、Arkaitz Correa、Diego Peña、Ramon Badorrey、Auke Meetsma、Adriaan J. Minnaard、Ben L. Feringa
DOI:10.1021/ja0585634
日期:2006.7.19
The mechanism of the enantioselective 1,4-addition of Grignardreagents to alpha,beta-unsaturated carbonyl compounds promoted by copper complexes of chiral ferrocenyl diphosphines is explored through kinetic, spectroscopic, and electrochemical analysis. On the basis of these studies, a structure of the active catalyst is proposed. The roles of the solvent, copper halide, and the Grignardreagent have