Regioselectivities of the Insertion Reactions of Unsymmetrical Alkynes with the Nickelacycles [NiBr(C<sub>6</sub>H<sub>4</sub>CH<sub>2</sub>PPh<sub>2</sub>-2)(L)] (L = Tertiary Phosphine)
作者:Alison J. Edwards、Stuart A. Macgregor、A. David Rae、Eric Wenger、Anthony C. Willis
DOI:10.1021/om0101083
日期:2001.6.1
important in controlling the regioselectivity of these insertion reactions. For example, insertion of MeC⋮CCO2Me into 2b forms mainly (4b), whereas CF3C⋮CCO2Et gives exclusively the alternative regioisomer (10b). On the basis of these observations, a model based on frontierorbital interactions is proposed. The alkynylphosphines RC⋮CPPh2 insert regiospecifically into the Ni−C bonds of 2a,b to give initially
已通过产物的多核NMR研究确定了各种炔烃向五元镍环的Ni-Ph键中插入的区域选择性(PR 3 = PEt 3(2a),PPhBz 2(2b))。在某些情况下,所得的七元镍环也已通过X射线分析进行了结构表征。结果表明,电子因素在控制这些插入反应的区域选择性中非常重要。例如,将MeC⋮CCO 2 Me插入2b形式主要为(4b),而CF 3 C⋮CCO 2Et仅给出替代的区域异构体(10b)。基于这些观察,提出了基于边界轨道相互作用的模型。炔基膦RC⋮CPPh 2区域特异性地插入2a,b的Ni-C键中,以产生最初的复合物,该复合物包含通过PPh 2基团与相邻金属的配位而形成的三元膦烷基环。这些物质是不稳定的,随后二聚(R = CO 2 Me)或经历重排(R = Me,Ph)得到双环镍环,其中金属是六元环和四元环的一部分。
Visible-Light-Promoted Unsymmetrical Phosphine Synthesis from Benzylamines
Herein, by applying visible-light photoredoxcatalysis, we have achieved the catalytic deaminativealkylation of diphenylphosphine and phenyl phosphine with benzylamine-derived Katritzky salts at room temperature. The use of Eosin Y as photoredox catalyst and visiblelight can largely promote the reaction. A series of unsymmetrical tertiary phosphines were successfully synthesized, including phosphines
在此,通过应用可见光光氧化还原催化,我们实现了二苯基膦和苯基膦与苄胺衍生的 Katritzky 盐在室温下的催化脱氨基烷基化反应。使用曙红 Y 作为光氧化还原催化剂和可见光可以大大促进反应。成功合成了一系列不对称的叔膦,包括具有三种不同取代基的膦,这些取代基很难获得。
Highly efficient C–C coupling reactions using metallated benzylphosphine complexes of palladium
作者:Scott Gibson、Douglas F. Foster、David J. Cole-Hamilton、Graham R. Eastham、Robert P. Tooze
DOI:10.1039/b100328n
日期:——
Phosphapalladacyclic complexes synthesised from ortho-bromobenzylphosphine ligands are effective catalysts for carbon–carbon bond forming reactions, exhibiting activity that compares with, and in several examples exceeds, that of existing systems.
This invention is directed to a class of compounds that can be both monodentate and bidentate in their association with a transition metal to form a catalyst for reactions such as the hydroformylation of olefins to produce aldehydes. The compounds contain two phosphorus atoms having different steric and/or electronic nature. In hydroformylation catalysts, the compounds advantageously can produce a variable n/iso product mixture of aldehyde products that can be varied by simply changing process variables such as [H
2
]/[CO] partial pressure gas ratio or temperature/inert gas partial pressure.