Synthesis, X-ray Geometry, and Anodic Behavior of Tris[2-(hydroxymethyl)phenyl]phosphane
摘要:
Tris[(monohydroxymethyl)phenyl]phosphane 5a and 5b were prepared, and the geometry of the ortho-isomer 5a was determined by X-ray diffraction. 5a was found to be propeller-like in shape, exhibiting a helical conformation with the three hydroxymethyl substituents standing on the same side as that with the phosphorus lone pair. Phosphanes 5a and 5b underwent electrochemical one-electron oxidation, giving rise to nonpersistent phosphoniumyl cation radicals 5a(.+) and 5b(.+). The low value of the anodic peak potential of 5a was explained by the fast decay of 5a(.+), which was rapidly rearranged to a phosphoranyl radical through the formation of a strong P-.-O bond. The fast oxidation of this intermediate phosphoranyl radical followed by a second cyclization led to the 1-[2-(hydroxymethyl)phenyl]spirobi[1H,3H-2,1-benzoxaphosphole] 7a, which was isolated in significant yield.
一维,二维和核Overhauser实验相结合,可以对三官能化的三苯基膦,三-(2-甲醛)三苯基膦1进行完整的NMR光谱表征。X射线单晶衍射研究表明,苯环的预期C 3-构型与每个甲醛基在空间上占据更有利的exo位置有关。羧醛功能中的两个采用顺式构象(指向磷的氧原子),而第三个显示反式构象,我们认为这与在晶格中采用氢键二聚体有关。对三官能化的有机磷化合物三-(2-正丙基亚氨基)三苯基膦5的可变温度1 H NMR研究表明,冻结出低温构象,其在ca下方缺乏平面对称性。24万。当用对映体纯的取代基取代正丙基官能团时,这种动态构象平衡的差向异构化是可能的。因此,对映体纯的三官能化的化合物三-{2-[((S)-α-甲基苄基亚氨基]}三苯基膦6由三-(2-羧醛)三苯基膦与(S)-α-甲基苄基胺缩合制得的,在非对映异构构象之间进行动态平衡,每个构象在磷原子上具有局部C 3-对称性。对于该过程,已经确定了50(2)kJ
palladium-catalysed reaction. Chiralphosphane imine ligands, however, are a successful class of compound, synthesized by Schiff base condensation of 2-formylphenyl(diphenyl)phosphane with optically active primary amines. An optimisation of this ligand type showed that the substituents at the stereogenic center in the imine part should be a hydroxymethyl group and a bulky alkyl group, with the best ligand
使用乙酰丙酮钯 (II) 和手性膦亚胺配体的原位催化剂将 1,5-二甲基巴比妥酸 (BS) 与乙酸烯丙酯烯丙基化,导致对映选择性形成 5-烯丙基-1,5-二甲基巴比妥酸 (ABS)主要产品 ee 高达 34%,3,5-二烯丙基-1,5-二甲基巴比妥酸 (AABS) 作为可能的副产品,ee 高达 34%。该反应是一种烯丙基烷基化反应,其立体选择性很难控制,因为新的立体中心是在亲核试剂中形成的,从与金属原子相反的一侧进行攻击。在这种钯催化的反应中,经典的旋光配体不具有任何对映选择性。然而,手性膦亚胺配体是一类成功的化合物,通过 2-甲酰基苯基(二苯基)膦与光学活性伯胺的席夫碱缩合合成。这种配体类型的优化表明,亚胺部分立体中心的取代基应该是一个羟甲基和一个庞大的烷基,最好的配体是 L-叔亮氨酸衍生物。其他类型的手性配体,例如膦胺和膦三亚胺,也进行了筛选。进行了阳离子 [(η3-烯丙基)Pd(2a)2]+
Asymmetrische katalysen XXXVI. Neue mehrzähnige liganden mit dem (S)-(α)-(2-Pyridyl)ethylrest; Rh-komplexe und enantioselektive hydrosilylierungen
作者:Henri Brumner、Heinrich Fisch
DOI:10.1016/0022-328x(87)85169-0
日期:1987.11
Starting from (S)-(−)-α-(2-pyridyl)ethylamine, 11 new multidentate ligands were prepared and characterized. Reaction with [Rh(cod)Cl]2 yielded the (cyclooctadiene)(imine)-RhI complexes (I–VII). The isolated complexes and the in-situ systems [Rh(cod)Cl]2/1–11 were used as enantioselective catalysts in the hydrosilylation of acetophenone with diphenylsilane. The resulting α-phenylethanol was found to
[EN] POROUS ORGANIC CAGE LIGAND CONTAINING P AND N AND COMPLEX CATALYST AND APPLICATION<br/>[FR] LIGAND À EFFET DE CAGE ORGANIQUE POREUX CONTENANT P ET N, CATALYSEUR COMPLEXE ET UTILISATION<br/>[ZH] 一种含P、N多孔有机笼配体及络合物催化剂和应用
Brunner, Henri; Rahman, A. F. M. Mokhlesur, Chemische Berichte, 1984, vol. 117, # 2, p. 710 - 724
作者:Brunner, Henri、Rahman, A. F. M. Mokhlesur
DOI:——
日期:——
Synthesis of a Tris(phosphaalkene)phosphine Ligand and Fundamental Organometallic Reactions on Its Sterically Shielded Metal Complexes
作者:Preston M. Miura-Akagi、Mika L. Nakashige、Caitlin K. Maile、Shelly M. Oshiro、Joshua R. Gurr、Wesley Y. Yoshida、A. Timothy Royappa、Colleen E. Krause、Arnold L. Rheingold、Russell P. Hughes、Matthew F. Cain
DOI:10.1021/acs.organomet.6b00250
日期:2016.7.11
A new tris(phosphaalkene)phosphine ligand (1) was synthesized via phospha-Wittig methodology. Metalation of 1 with [RhCl(C2H4)(2)](2) and [IrCl(COE)(2)](2) (COE = cyclooctene) produced trigonal bipyramidal metal chlorides 2a (M = Rh) and 2b (M = Ir) in which the ligand coordinates in a tetradentate fashion. X-ray crystallographic studies on 1 center dot 1.5THF, 2a center dot 5CHCl(3), and 2b center dot 2.5CHCl(3) combined with DFT calculations revealed a pronounced change in hybridization of the phosphaalkene phosphorus atoms upon coordination to the Rh/Ir centers, resulting in highly sterically congested metal complexes. Nucleophilic substitution on 2a with NaN3 afforded Rh-N-3 complex 3; computational analysis, IR spectroscopy, and N-15H-1} NMR spectroscopy on isotopologue N-15-3 provided additional structural insights. Halide abstraction of the chloride in 2b with AgOTf in the presence of acetonitrile afforded cationic Ir-NCMe complex 4. Evidence of the bound acetonitrile unit was obtained by 2D NMR spectroscopy and deuterium labeling studies.