Activation of Nitriles by Metal Ligand Cooperation. Reversible Formation of Ketimido- and Enamido-Rhenium PNP Pincer Complexes and Relevance to Catalytic Design
作者:Matthias Vogt、Alexander Nerush、Mark A. Iron、Gregory Leitus、Yael Diskin-Posner、Linda J. W. Shimon、Yehoshoa Ben-David、David Milstein
DOI:10.1021/ja4071859
日期:2013.11.13
the displacement of benzyl cyanide from 9 by CO. Computational studies suggest a stepwise activation of the nitriles by 4, with remarkably low activation barriers, involving precoordination of the nitrile group to the Re(I) center. The enamido complex 9 reacts via β-carbon methylation to give the primary imino complex cis-[Re(PNP(tBu)-HN═CC(Me)Ph)(CO)2]OTf 11. Upon deprotonation of 11 and subsequent
Biologische Abbauversuche II. Über den biologischen Abbau von Glutarsäureimiden
作者:J. Kebrle、K. Hoffmann
DOI:10.1002/hlca.19560390318
日期:——
In view of the diverse therapeutic interest glutarimides have found recently, the metabolism of several glutarimide derivatives has been studied by feeding experiments upon dogs. The products eliminated in the urine are suggestive of a biological degradation of this type of compounds by dehydrogenation, i. e. by oxidative degradation.
Stereochemical Studies. XXV. The Absolute Configuration and Optical Purity of (+)-4-Methyl-4-phenyl-2-cyclohexenone
作者:GENJI OTANI、SHUNICHI YAMADA
DOI:10.1248/cpb.21.2119
日期:——
(+)-4-Methyl-4-phenyl-2-cyclohexenone ((+)-I), obtained by asymmetric synthesis, was chemically correlated to (S)-(+)-2-methyl-2-phenylbutanoic acid, whose absolute configuration is known. It was shown that (+)-4-methyl-4-phenyl-2-cyclohexenone ((+)-I) has (R) configuration. In determining the configuration, the optical ratation of optically pure (+)-4-methyl-4-phenyl-2-cyclohexenone ((+)-I) was estimated to be +130°in ethanol at D ray.
(通过不对称合成获得了(+)-4-甲基-4-苯基-2-环己烯酮((+)-I),并将其与已知绝对构型的(S)-(+)-2-甲基-2-苯基丁酸进行了化学关联。结果表明,(+)-4-甲基-4-苯基-2-环己烯酮((+)-I)具有 (R) 构型。在确定构型时,估计光学纯的(+)-4-甲基-4-苯基-2-环己烯酮((+)-I)在乙醇中 D 射线处的光学比值为 +130°。
Rhodium-catalyzed michael additions of activated nitriles to α,β - unsaturated esters
The Michael additions of activatednitriles to methyl acrylate (MA) and methyl vinyl ketone (MVK) proceeds with fair to high yields (46–92%) in the presence of catalytic amount of HRh(CO)(PPh3)31 under mild eaction conditions.
Cesium Carbonate Supported on Alumina for the Michael Addition of Diethyl Malonate to Methyl Acrylates
作者:Tetsunari Hida、Kenichi Komura、Yoshihiro Sugi
DOI:10.1246/bcsj.20110115
日期:2011.9.15
The cesium salts supported on γ-Al2O3 were highly active catalysts for the Michael addition of diethyl malonate (1) to methyl acrylate (2) in toluene as solvent. The use of a limited amount of 2 gave diethyl [2-(methoxycarbonyl)ethyl]malonate (3), however the formation of diethyl bis[2-(methoxycarbonyl)ethyl]malonate (4) was enhanced by the increase in amounts of 2. Catalytic activities were easily recovered by the calcination of used catalysts. IR and XRD observations indicate that the active catalytic species are Cs2CO3 on Al2O3. The use of malononitrile enhanced the formation of the diadduct as principal products by addition to methyl acrylate. Other methyl acrylates, such as methyl methacrylate and methyl crotonate, gave low yield of the products.