Evidence on palladacycle-retaining pathway for Suzuki coupling. Inapplicability of Hg-drop test for palladacycle catalysed reactions
摘要:
Investigation of the model atroposelective Suzuki reaction catalysed by chiral CN-palladacycles have shown that two types of catalytic cycle may operate simultaneously, with strong dependence of their contributions upon the palladacycle structure and conditions used. Dominant contribution of palladacycle retaining pathway was provided by the non-metallocene planar chiral iminate CN-palladacycle (R-pl)-4a using as catalyst, in reaction performed in toluene under aerobic conditions with KF as a base, affording (S-a)-2-methoxy-1,1'-binaphthalene with enantioselectivity up to 53% ee. The catalyst was recovered almost quantitatively as an iodide-bridged dimer, whose structure was confirmed by an X-ray diffraction study of its phosphine derivative. It was also shown that the common Hg drop test was unsuitable for mechanistic testing of palladacycle-catalysed reactions because of the transmetallation product formation, whose structure was confirmed by an X-ray diffraction study. (C) 2013 Elsevier B.V. All rights reserved.
Axially chiral P-N ligands for the copper catalyzed β-borylation of α,β-unsaturated esters
作者:William J. Fleming、Helge Müller-Bunz、Vanesa Lillo、Elena Fernández、Patrick J. Guiry
DOI:10.1039/b900741e
日期:——
The synthesis and resolution of a new axially chiral Quinazolinap ligand are reported. The application of this and other related P-N ligands to the copper catalyzed β-borylation of α,β-unsaturated esters resulted in conversions of up to 100% and ee values of up to 79%. A diastereomerically pure palladacycle of the new ligand was characterised by X-ray crystallography.
Hemilability and regioselectivity in palladium and platinum complexes of dppm(E) [E = O, S, Se] ligands
作者:J.W. Faller、Tracey Friss、Jonathan Parr
DOI:10.1016/j.jorganchem.2010.08.015
日期:2010.11
nonrigidity in a series of mixed P^PE donor ligands where E = O, S, or Se have been studied in palladium and platinumcomplexes of the type [Mκ2-(dimethylamino)ethylnaphthyl-C,N)}(P^PE)][SbF6] where P^PE = Ph2PCH2P(E)Ph2.The role of the donor in hemilability, regioselectivity and the binding preferences of particular donors trans to the metallated carbon atom were also investigated. NMR parameters including
Hemilability和nonrigidity在一系列混合的P ^ P Ê供体配体,其中ë = O,S,或Se已在式[M的钯和铂络合物进行了研究κ 2 - (二甲基氨基)ethylnaphthyl- C,N)} (P ^ P ë)] [的SbF 6 ]其中P ^ P ë =苯基2 PCH 2 P(ë)PH 2 .The在hemilability,区域选择性供体的特定供体的结合偏好作用和反式的金属化的碳原子还进行了调查。NMR参数包括与195 Pt和77的偶联研究了硒的顺式和反式异构体。2 J 13 C– 77 Se偶联的量级可以轻松地区分顺式和反式异构体。在dppm(Se)配合物的氨基甲基之一中观察到较大的贯穿空间13 C– 77 Se 3 J偶联。
Synthesis and resolution of a new P-chiral hydroxy phosphine
The synthesis of the functionalized P-chiral phosphine BzPhPCH(OH)Ph}and its resolution by palladium metallacycles is reported. The cyclopalladated compound containing the primary amine 1-(1-naphthyl)ethylamine has been shown to be a better resolvingagent for this phosphine than the corresponding metallacycle containing the tertiary amine N,N-dimethyl-1-(1-naphthyl)ethylamine
Domino cyclization–alkylation protocol for the synthesis of 2,3-functionalized indoles from o-alkynylanilines and allylic alcohols
作者:Chang Xu、Vinod K. Murugan、Sumod A. Pullarkat
DOI:10.1039/c2ob25379h
日期:——
A practical and efficient protocol for the one-pot synthesis of 2,3-substituted indoles was developed via a palladacycle catalyzed domino cyclizationâalkylation reaction involving 2-alkynylanilines and allylic alcohols under mild conditions without any additives.
Asymmetric synthesis of keto-substituted P-chiral phosphines by means of an unusual exo/endo-stereochemically controlled Diels–Alder reaction
作者:Pak-Hing Leung、Soh-Kheang Loh、Jagadese J. Vittal、Andrew J. P. White、David J. Williams
DOI:10.1039/a705830f
日期:——
An asymmetric DielsâAlder reaction between 1-phenyl-3,4-dimethylphosphole and ethyl vinyl ketone promoted by a chiral organopalladium complex gives the corresponding keto-substituted phosphine ligands in which the keto group can be stereospecifically located in the endo- or exo-positions of the phosphanorbornene skeleton.