Chromium-53 nuclear magnetic resonance studies of pentacarbonylchromium carbene complexes
作者:Andreas. Hafner、Louis S. Hegedus、Guy. DeWeck、Bruce. Hawkins、Karl H. Doetz
DOI:10.1021/ja00233a018
日期:1988.12
The sup 53}Cr NMR spectra of 46 chromium-carbene complexes were recorded, and chemicalshift and line width data are reported, along with associated infrared, uv-visible, and sup13}CNMR spectroscopic data. The sup 53}Cr chemicalshifts correlated very well with the donor-acceptor properties of the carbene ligand and were quite sensitive to steric influences on efficiency of pi}-overlap of the
Stereoselective aldol addition reactions of Fischer carbene complexes via electronic tuning of the metal center for enolate reactivity
作者:William D. Wulff、Benjamin A. Anderson、Amanda J. Toole、Yao-Chang Xu
DOI:10.1016/0020-1693(94)03874-0
日期:1994.6
chromium complexes and pentacarbonylmethyl (dialkylamino)methylene chromium complexes with aldehydes and ketones were examined. The reactions of the phosphine complexes give only aldol condensation products, but the desired aldol addition products can be isolated from the reactions of amino carbenecomplexes. This was attributed to the greater reactivity of the enolates of amino carbenecomplexes which
摘要研究了四羰基(膦)甲基(甲氧基)亚甲基铬配合物和五羰基甲基(二烷基氨基)亚甲基铬配合物与醛和酮的醛醇缩合反应。膦配合物的反应仅产生羟醛缩合产物,但是所需的羟醛加成产物可以从氨基卡宾配合物的反应中分离出来。这归因于氨基卡宾配合物的烯醇化物的更高的反应性,这通过确定二甲基氨基配合物13的热力学酸性来支持(p K a = 20.4)。氨基配合物与α-手性醛的醛醇缩合反应具有很高的面部选择性,可与醛醇缩合反应中针对面部选择性开发的最佳方法相媲美。氨基络合物的醛醇缩合反应可被认为是酰胺的直接合成子,因为酰胺官能团可在这些络合物的醛醇加合物的氧化裂解中获得。为了说明卡宾配合物的多功能性,还通过光诱导的碳均质脱金属反应证明了,卡宾配合物的独特反应与醛醇加成反应相结合,可提供强大而新颖的整体转化。
Improved synthesis of (aminocarbene)chromium(0) complexes with use of C8K-generated Cr(CO)52-. Multivariant optimization of an organometallic reaction
作者:Mark A. Schwindt、Tore Lejon、Louis S. Hegedus
DOI:10.1021/om00160a033
日期:1990.10
The electrochemical activity of heteroatom-stabilized Fischer-type carbene complexes
A cyclic voltammetry study of some alkoxy, amino and hydrazino carbene complexes of chromium and tungsten has been performed, affording for the first time a detailed overview on the electrochemical activity of this useful and versatile compound class, focusing on the modulating effects of both the carbene metal and substituents.The interest for the above results is also related to the possibility of using Fischer carbenes as new electrochemical active probes for labeling 'peptide nucleic acids, which are DNA analogues, for diagnostic purposes. (c) 2005 Elsevier B.V. All rights reserved.
Hegedus, Louis S.; Schwindt, Mark A.; De Lombaert, Stéphane, Journal of the American Chemical Society, 1990, vol. 112, # 6, p. 2264 - 2273
作者:Hegedus, Louis S.、Schwindt, Mark A.、De Lombaert, Stéphane、Imwinkelried, Rene