Macrocyclic Salen–Bis-NHC Hybrid Ligands and Their Application to the Synthesis of Enantiopure Bi- and Trimetallic Complexes
作者:Melanie Mechler、Wolfgang Frey、René Peters
DOI:10.1021/om500762r
日期:2014.10.13
Salen and NHC ligands are among the most important ligands for homogeneous catalysis. We have recently reported bimetallic complexes, in which both motifs have been merged for the first time. However, the intermetallic distances, which play a crucial role for cooperative bimetallic catalysis, were probably not appropriate in these first-generation hybrid catalysts. To generate heterobimetallic salen/NHC
Salen和NHC配体是均相催化最重要的配体。我们最近报道了双金属配合物,其中两个基序已首次合并。但是,对于协同双金属催化作用至关重要的金属间距离可能不适用于这些第一代杂化催化剂。为了产生具有适合于协作催化的金属间距离的杂双金属salen / NHC杂化配合物,在本研究中已经制备了具有salen和两个连接的NHC供体部分的手性大环杂化配体。对于配体形成,使用手性对映体纯二胺以及手性对映体纯双咪唑,并且根据两种手性来源的构型发现匹配/不匹配的情况。有效地完成了2 O 2协调领域。随后对Ag(I),Cu(I),Au(I)和Pd(II)的NHC单元进行了配位,在后者情况下,是通过Pd 2(dba)3的氧化金属转移作用实现的。Ni / Ag 2和Pd / Ag 2配合物的X射线晶体结构分析显示,大环起伏很大,其中与NHC结合的Ag(I)中心之一紧邻与salen结合的Ni(II)或Pd。 (II)中
Palladium(II)-catalyzed coupling reactions of alkynes and allylic compounds initiated by intramolecular carbopalladation of alkynes
作者:Guosheng Liu、Xiyan Lu
DOI:10.1016/s0040-4039(02)01512-5
日期:2002.9
Under divalent palladium catalysis, a highly regio- and stereoselectivecoupling reaction of alkynes with allylhalides initiated by cyclocarbopalladation of alkynes proceeded smoothly in the presence of excess halide ions. The reaction involves intramolecular carbopalladation, allylic compound insertion into the vinylicPd bond and quenching the CPd bond by β-heteroatom elimination in one step without
Intramolecular Diels-Alder reactions of 1,2,4-triazines. Synthesis of 2,3-cyclopentenopyridines and 5,6,7,8-tetrahydroquinolines
作者:Edward C. Taylor、John E. Macor、Larry G. French
DOI:10.1021/jo00005a027
日期:1991.3
2,3-Cyclopentenopyridines and 5,6,7,8-tetrahydroquinolines are prepared by intramolecular Diels-Alder reactions of appropriately substituted 1,2,4-triazines. Two general routes to the requisite triazine precursors are described.
Julia,M.; James,C., Comptes Rendus Hebdomadaires des Seances de l'Academie des Sciences, 1962, vol. 255, p. 959 - 960
作者:Julia,M.、James,C.
DOI:——
日期:——
Intramolecular and Intermolecular Mn(III)-Induced Carbon Monoxide Trapping Reactions of Alkynes with Malonate and Cyano Ester Units
作者:Kazumi Okuro、Howard Alper
DOI:10.1021/jo9607673
日期:1996.1.1
Intra- and intermolecular carbon monoxide trapping reactions of alkynes with malonates and cyano esters were developed using a Mn(III)-induced oxidative system. Phenylacetylene was treated with diethyl ethylmalonate in the presence of Mn(OAc)(3) . 2H(2)O, in AcOH-CH3CN (1:1) under carbon monoxide, affording (Z)-4,4-dicarbethoxy-2-phenyl-2-hexenoic acid. Similarly, intramolecular reactions of 4-alkynylmalonates and cyanoacetates proceeded regio- and stereoselectively under the same conditions to afford the corresponding methylenecycloalkanecarboxylic acids in moderate yields. The reaction involves carbon monoxide trapping of vinyl radicals which are formed by the addition of malonate or cyanoacetate radicals induced by Mn(III) to alkynes.