297176-74-0Relevant academic research and scientific papers
Enantioselective Inverse Electron Demand (3 + 2) Cycloaddition of Palladium-Oxyallyl Enabled by a Hydrogen-Bond-Donating Ligand
Zheng, Yin,Qin, Tianzhu,Zi, Weiwei
supporting information, p. 1038 - 1045 (2021/01/25)
Cycloaddition reactions between oxyallyl cations and alkenes are important transformations for the construction of ring systems. Although (4 + 3) cycloaddition reactions of oxyallyl cations are well-developed, (3 + 2) cycloadditions remain rare, and an as
Preparation, coordination and catalytic use of planar-chiral monocarboxylated dppf analogues
Lamac, Martin,Cisarova, Ivana,Stepnicka, Petr
, p. 1549 - 1562 (2009/10/30)
A novel polar dppf derivative possessing only planar chirality, 1′,2-bis(diphenylphosphino)-ferrocene-1-carboxylic acid (Hdpc), has been synthesised in racemic form and resolved into enantiomers via esters with d-glucose diacetonide ((Rp)- and (Sp)-3). (R p)-Hdpc was further converted to a series of N-substituted amides that were studied as ligands for Pd-catalysed enantioselective allylic alkylation of racemic (E)-1,3-diphenylprop-2-en-1-yl acetate or ethyl carbonate with malonate esters, showing high activity and good enantioselectivity (er up to 10: 90). The catalytic results were correlated with the structural data (X-ray diffraction and solution NMR) for (η3-allyl)palladium(ii) complex (Rp)-[Pd(η3-1,3-Ph2C 3H3){Fe(η5-C5H 3-1-(C(O)NHCH2Ph)-2-(PPh2-κP)) (η5-C5H4PPh2-κP)}]ClO 4 (16) as a model of the plausible reaction intermediate. A further study into the coordination properties of Hdpc led to isolation of chelate complex [PdCl2(Hdpc-κ2P,P′)] (12). The crystal structures of rac-Hdpc, methyl ester of (Rp)-Hdpc, glycoside (R p)-3, and 12·Me2CO suggested a close structural relationship between dppf and Hdpc. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2009.
Synthesis, characterization and diastereoselective coordination of a planarly chiral, hybrid ferrocene ligand, (Sp)-2-(diphenylphosphino)ferrocenecarboxylic acid
Stepnicka, Petr
, p. 567 - 575 (2007/10/03)
Hydrolytic cleavage of the dihydrooxazole ring in (Sp)-2-{2-(diphenylphosphino)ferrocenyl}-4-(1-methylethyl)-4, 5-dihydrooxazole affords the planarly chiral functionalized phosphine, (Sp)-2-(diphenylphosphino)-ferrocenecarboxylic acid, (Sp)-Hpfc, in two steps and 65% yield. (Sp)-Hpfc, all intermediates and the corresponding phosphine oxides were characterized by elemental analysis, multinuclear NMR and IR spectroscopy, and by optical rotation measurements. Solid-state structures of the phosphine oxides were further studied by X-ray crystallography to reveal extensive hydrogen bonding of various types. Neutralization of (Sp)-Hpfc with tert-BuOK followed by metathesis of the in situ obtained salt with [{RuCl(μ-Cl)(η6-p-cymene)}2] gives a chelate complex [RuCl(pfc-k2O,P)(η6-p-cymene)], 5, as a kinetic 1:1 mixture of diastereoisomers. Upon standing in solution, the diastereomeric mixture undergoes a spontaneous resolution to yield the thermodynamically preferred diastereoisomer (RRu,Sp)-5 whose configuration was corroborated by X-ray crystallography; the (RRu,Sp)-5 diastereoisomer was obtained in 82% yield by crystallization. The epimerization is likely initiated by a reversible Ru-O bond cleavage and suggests a hemilabile coordination of the (Sp)-pfc- anion. However, according to NMR spectra pure (RRu,Sp)-5 does not undergo diastereoisomer interconversion in a solution, which is in agreement with an unfavourable geometric arrangement of the (SRu)-epimer.
Palladium-catalyzed asymmetric allylic alkylations of cycloalkenyl acetates with planar chiral phosphino-ferrocene carboxylic acids
You, Shu-Li,Luo, Yu-Mei,Deng, We-Ping,Hou, Xue-Long,Dai, Li-Xin
, p. 845 - 849 (2007/10/03)
New phosphino-ferrocene carboxylic acids with only planar chirality (Sp)-3 and (Sp)-4 have been synthesized conveniently from (S,Sp)-5 and (S,Sp)-7. They were used as ligands in palladium-catalyzed allylic alkylation of cycloalkenyl acetates. With ligand (Sp)-4, high yield and good ee were given for reactions of a series of cycloalkenyl acetates and nucleophiles.
