An Efficient Method for the Preparation of Tertiary Esters by Palladium-Catalyzed Alkoxycarbonylation of Aryl Bromides
摘要:
The palladium-catalyzed alkoxycarbonylation of aryl bromides is described for the efficient preparation of tertiary esters. The protocol proved compatible with a wide variety of functionallzed (hetero)aromatic bromides, as well as several different sterically hindered tertiary alcohols, affording the alkoxycarbonylated products in high yields. Finally, the formation of aromatic trityl esters is discussed.
作者:Kun-Woo Kim、Yong-Joo Kim、Hye Jin Lim、Soon W. Lee
DOI:10.1002/bkcs.10590
日期:2015.12
which shows a Pd(II) metal, a DPPF ligand, and two CF3COO ligands. TwoCp rings in theDPPF ligand are not perfectly parallel,with a dihedral angle of 4.4(4) . ThePd Fe separation of 4.1932(8)A indicates no direct interactions between these two metals. We examined the ligand exchange reaction of complex 8 with 2 equiv of NaN3 in CH2Cl2 (Scheme 2). The reaction readily proceeded to give a Pd(II) azide complex
羧酸盐通过它们的氧原子以末端、螯合或桥接的方式与过渡金属配位,并在各种催化反应中充当活性配体。众所周知,具有三氟乙酸盐 (TFA) 配体的过渡金属配合物比相应的乙酸盐对应物具有更高的溶解度和结晶度,具体取决于金属的特性。特别是,后过渡金属的 TFA 配合物是多种有机反应的有效催化剂,包括异氰化物或丁二烯的聚合以及 CO 和烯烃的共聚。此外,在有机底物的有氧氧化、乙烯基转移形成烯酰胺或在 Pd 催化剂存在下有机底物的氧化环化方面,这种配合物比相应的醋酸盐配合物表现出更高的效率。尽管已经报道了许多催化 Suzuki-Miyaura CC 偶联反应,但涉及后过渡金属-TFA 配合物的反应仍然很少见。出于这个原因,我们试图开发一种新的合成途径来合成具有螯合膦配体的 Pd-TFA 配合物,以用于这种偶联反应。在这项工作中,我们制备了一系列 Pd(II)-TFA-(螯合二膦)配合物,并研究了芳基卤化物和芳基硼酸的催化
Mild N-Alkylation of Amines with Alcohols Catalyzed by the Acetate Ru(OAc)<sub>2</sub>
(CO)(D<i>i</i>
PPF) Complex
作者:Rosario Figliolia、Salvatore Baldino、Hans G. Nedden、Antonio Zanotti-Gerosa、Walter Baratta
DOI:10.1002/chem.201702996
日期:2017.10.17
The acetate complex Ru(OAc)2(DiPPF) (2) obtained from Ru(OAc)2(PPh3)2 (1) and 1,1′‐bis(diisopropylphosphino)ferrocene (DiPPF) reacts cleanly with formaldehyde affording Ru(OAc)2(CO)(DiPPF) (3) in high yield. The monocarbonyl complex 3 (0.4‐2 mol %) efficiently catalyzes the N‐alkylation of primary and secondary alkyl and aromatic amines using primary alcohols ROH (R=Et, nPr, nBu, PhCH2) under mild
从Ru(OAc)2(PPh 3)2 (1)和1,1'-双(二异丙基膦基)二茂铁(D i PPF)获得的乙酸盐络合物Ru(OAc)2(D i PPF)(2)与甲醛以高收率提供Ru(OAc)2(CO)(D i PPF)(3)。单羰基络合物 3(0.4-2 mol%)使用伯醇ROH(R = Et,n Pr,n Bu,PhCH 2)在温和的反应条件下(30-100°C),醇/胺的摩尔比为10-100。该一水合物期RuH(OAc)(CO)的形成(d我PPF)(4)已经通过反应观察到3与我PrOH中在网的存在3在RT下通过平衡反应。
Carbon−Carbon Bond-Forming Reductive Elimination from Arylpalladium Complexes Containing Functionalized Alkyl Groups. Influence of Ligand Steric and Electronic Properties on Structure, Stability, and Reactivity
作者:Darcy A. Culkin、John F. Hartwig
DOI:10.1021/om049726k
日期:2004.7.1
of the enolate or cyanoalkyl group, and complexes with more substitution at the α-carbon were less stable. Arylpalladium methyl, benzyl, enolate, cyanoalkyl, and trifluoroethyl complexes underwent carbon−carbon bond-forming reductiveelimination upon heating. Reductiveelimination was faster from complexes with electron-withdrawing substituents on the palladium-bound aryl group and with sterically hindered
一系列具有式[(DPPBz)Pd(Ar)(R)]的芳基钯烷基络合物(DPPBz = 1,2-双(二苯基膦基)苯; R =甲基,苄基,烯醇盐,氰基烷基,三氟烷基或丙二酸酯)具有我们准备揭示空间和电子参数对结构,稳定性和反应性的影响。由EtPh 2 P,1,1'-双(二异丙基膦基)二茂铁(D i(PrPF)和BINAP制备以评估辅助配体的作用。烯醇盐和氰基烷基络合物的配位模式通过光谱法结合X射线晶体学测定。在没有空间位阻的情况下,如果烯醇盐或氰基烷基反式为膦,则电子键合C键异构体;如果烯醇酸酯反式为芳基,则为O键异构体。烯醇盐和氰基烷基络合物的热力学稳定性受烯醇盐或氰基烷基的空间性质控制,并且在α-碳上具有更多取代的络合物较不稳定。芳基钯甲基,苄基,烯醇盐,氰基烷基和三氟乙基络合物在加热时进行碳-碳键形成还原性消除。从在钯结合的芳基上具有吸电子取代基和在空间上受阻的烷基上形成配合物,还原消除速
Room-Temperature Benzylic Alkylation of Benzylic Carbonates: Improvement of Palladium Catalyst and Mechanistic Study
作者:Ryoichi Kuwano、Masashi Yokogi、Ken Sakai、Shigeyuki Masaoka、Takashi Miura、Sungyong Won
DOI:10.1021/acs.oprd.9b00210
日期:2019.8.16
nucleophilic substitution of benzyl carbonates was improved by using 1,1′-bis(diisopropylphosphino)ferrocene (DiPrPF) as the ligand. The [Pd(η3-C3H5)(cod)]BF4–DiPrPF catalyst allows the benzylic substitution with soft carbanions to proceed even at 30 °C, affording the desired products in high yields (up to 99% yield). Thermally unstable pyridylmethyl esters are employable as the electrophilic substrates
为苄基碳酸酯的亲核取代的钯催化剂是通过使用1,1'-双(二异丙基)二茂铁(d改善我配体PrPF)为。的[将Pd(η 3 -C 3 H ^ 5)(COD)] BF 4 -D我PrPF催化剂允许与软碳负离子苄基取代,甚至在30℃下进行,得到高产率的所需产物(高达99%屈服)。热不稳定的吡啶基甲基酯可用作亲电底物,用于用改进的催化剂进行苄基烷基化。此外,我们研究了通过D i PrPF配体催化苄基烷基化的机理。钯(0)配合物D iPrPF在室温下激活苄基C–O键以形成(苄基)钯(II)中间体。苄基配体的配位模式将是η之间的平衡1 -和η 3 -manner。亲核试剂将优先与η反应3 -苄基配体,得到所需产物。
Organometallic Fe-Fe Interactions: Beyond Common Metal-Metal Bonds and Inverse Mixed-Valent Charge Transfer
作者:Mark R. Ringenberg、Max Schwilk、Florian Wittkamp、Ulf-Peter Apfel、Wolfgang Kaim
DOI:10.1002/chem.201605527
日期:2017.2.3
the mixed‐valent monocations are due to an unprecedented “inverse” inter‐valence charge transfer from the electron‐rich iron(II) in the ferrocene backbone to the electron‐deficient tricarbonyliron(I). Protonation of complex 1 results in the formation of the structurally characterized hydride [1H]BF4, which reacts with acetone to form the dication, 12+, and isopropanol. While the hydride [2H]BF4 was found
化合物[Fe(CO)3(dRpf)] n +,n = 0,1,2和dRpf = 1,1'-双(二环己基膦基)二茂铁([ 1 ] n +)或1,1'-bis(二异丙基膦基)二茂铁([ 2 ] n +)是通过光解和氧化还原反应获得的两步可逆氧化还原系统。铁-铁的距离在氧化时从大约4Å减少到大约3Å,氧化主要发生在三羰基铁部分。尽管计算出二茂铁的氧化仅在激发态下发生,但混合价单阳离子的近红外吸收是由于前所未有的“逆”价电荷从二茂铁主链中的富电子铁(II)转移至二价铁而形成的。缺电子的三羰基铁(I)。配合物1的质子化导致结构上表征的氢化物[ 1 H] BF 4形成,该氢化物与丙酮反应形成二价离子1 2+和异丙醇。而氢化物[发现2 H] BF 4不稳定,丙酮中2的质子化导致2 2+的干净形成,形式上为氢转移。