183583-04-2Relevant articles and documents
Synthesis of rac-ɑ-aryl propionaldehydes via branched-selective hydroformylation of terminal arylalkenes using water-soluble Rh-PNP catalyst
Gao, Peng,Ke, Miaolin,Ru, Tong,Liang, Guanfeng,Chen, Fen-Er
, p. 830 - 834 (2021/08/26)
This work detailed the preparation of a class of water-soluble PNP ligands that differed by the nature of the substitute on phenyl ring of ligands. These ligands were incorporated into water-soluble rhodium-PNP complex catalysts that were used to regioselective hydroformylation of a series of terminal arylalkenes, providing efficient access to rac-α-aryl propionaldehydes in good to excellent yield (up to 97%) and branched-regioselectivity (up to 40:1 b/l ratio). Furthermore, gram-scale and diverse synthetic transformation demonstrated synthetic application of this methodology for non-steroidal antiinflammatory drugs.
MICROCAPSULES AND PROCESSES FOR THEIR PREPARATION
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Page/Page column 28-30, (2019/06/11)
The present invention provides microcapsules encapsulating hydrophilic or hydrophobic active agents in an inorganic shell, processes for their preparation and compositions comprising them.
Synthesis of tetra-pincer nickel(ii) and palladium(ii) complexes of resorcin[4]arene-octophosphinite [Res(OPR2)8] and rhodium-catalyzed regioselective hydroformylation reaction
Ananthnag, Guddekoppa S.,Mondal, Dipanjan,Mague, Joel T.,Balakrishna, Maravanji S.
, p. 14632 - 14641 (2019/10/16)
The condensation reaction of resorcinol with pentanal yielded resorcin[4]arene 1 which on bromination using N-bromosuccinimide at room temperature produced tetra-bromide derivative 2. The reactions of 2 with chlorodiphenylphosphine and o-phenylenephosphoro-chloridite yielded octaphosphinite 3 (hereafter referred to as octaphos) and octaphosphite 4, respectively. The reactions of 3 with Ni(COD)2 or Pd2(dba)3·CHCl3 in appropriate molar ratios yielded tetra-pincer complexes 5 and 6, respectively. The structures of both the complexes were established by single crystal X-ray diffraction studies. The resorcin[4]arene backbone adopts a boat structure in these complexes. Typically, the Rh-catalyzed hydroformylation of styrene prevalently delivers a branched (b) chiral aldehyde. A unique resorcin[4]arene skeleton based octaphos 3 was employed in the Rh-catalyzed hydroformylation of styrene. The hydroformylation of styrene with a metal to ligand ratio of 1:1 (M:L) was found to be regioselective, producing a linear (l) aldehyde as a major product with 100% conversion in 3 h. The l:b ratio surprisingly increased when the ortho positions of styrene were populated by methyl and chloro substituents. The hydroformylation of p-nitro styrene triggered a remarkably high linear:branched aldehyde ratio of 2.4 (71% linear aldehyde) despite its electron withdrawing nature. The highest linear selectivity of 97% (l:b ratio 27.8) was achieved in the case of 2,4,6-trimethylstyrene.
Copper-catalyzed vinylogous aerobic oxidation of unsaturated compounds with air
Zhang, Hai-Jun,Schuppe, Alexander W.,Pan, Shi-Tao,Chen, Jin-Xiang,Wang, Bo-Ran,Newhouse, Timothy R.,Yin, Liang
supporting information, p. 5300 - 5310 (2018/04/24)
A mild and operationally simple copper-catalyzed vinylogous aerobic oxidation of β,γ- and α,β-unsaturated esters is described. This method features good yields, broad substrate scope, excellent chemo- and regioselectivity, and good functional group tolerance. This method is additionally capable of oxidizing β,γ- and α,β-unsaturated aldehydes, ketones, amides, nitriles, and sulfones. Furthermore, the present catalytic system is suitable for bisvinylogous and trisvinylogous oxidation. Tetramethylguanidine (TMG) was found to be crucial in its role as a base, but we also speculate that it serves as a ligand to copper(II) triflate to produce the active copper(II) catalyst. Mechanistic experiments conducted suggest a plausible reaction pathway via an allylcopper(II) species. Finally, the breadth of scope and power of this methodology are demonstrated through its application to complex natural product substrates.
Rh/Cu2O nanoparticles: Synthesis, characterization and catalytic application as a heterogeneous catalyst in hydroformylation reaction
Jagtap, Samadhan A.,Bhosale, Manohar A.,Sasaki, Takehiko,Bhanage, Bhalchandra M.
, p. 162 - 168 (2016/12/06)
In this work, we report a rapid protocol for the synthesis of Rh/Cu2O nanoparticles (Rh/Cu2O NPs) in aqueous medium using microwave route. The microwave energy acts as driving force in synthesis which makes the process economical. The obtained nanoparticles were characterized with the help of FEG-SEM, TEM, HRTEM, EDS, XRD, FT-IR and ICP-AES techniques. The prepared Rh/Cu2O nanoparticles gave 100% yield of uniform spherical morphology. This is a simple, inexpensive and time saving protocol for synthesis of Rh/Cu2O nanoparticles than conventional methods. Furthermore, we showed the catalytic application of Rh/Cu2O nanoparticles in hydroformylation reaction for the conversion of 1-hexene to 1-hexanal at mild reaction conditions such as Rh/Cu2O NPs (10 mg), 35 bar pressure of H2/CO at 360 K. The reaction provides 99% conversion and high selectivity (>90%) toward aldehydes with branched aldehyde is a major product. Notably the reaction does not require the any phosphine ligand source, low catalyst loading, low temperature with major advantage of catalyst recyclability.
ANTI-HCMV COMPOSITIONS AND METHODS
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Page/Page column 97; 101, (2016/06/06)
This document relates to compounds useful as agents for preventing or treating human cytomegalovirus (HCMV) infections.
Enantioselective hydroformylation of 2- and 4-substituted styrenes with PtCl2[(R)-BINAP] + SnCl2‘in situ’ catalyst
Pongrácz, Péter,Kollár, László
, p. 118 - 123 (2016/10/25)
Two sets of styrenes possessing various substituents either in ortho or para position were hydroformylated in the presence of ‘in situ’ catalyst formed from PtCl2[(R)-BINAP] and tin(II) chloride. The reversal of the absolute configuration of the preferred enantiomers was observed using both sets of substrates by the variation of the reaction temperature in the range of 40–100 °C. In case of the 4-substituted styrenes, the reversal temperature of the enantioselectivity shows correlation with the Hammett substituent constants, i.e., with the electron donor or electron acceptor properties of the para-substituents. This phenomenon was explained by the reversible formation of the Pt-branched alkyl intermediates, leading to the corresponding (R)- and (S)-enantiomers of 2-arylpropanals. Strong substituent effect on the regioselectivity was observed in the hydroformylation of 2-substituted styrenes: the presence of substituents characterised by larger steric parameter resulted in the highly favoured formation of the linear aldehyde. For instance, regioselectivities of 45%, 22% and 7% towards branched aldehyde were obtained with styrene, 2-fluoro- and 2-bromostyrene, respectively, at 80 °C reaction temperature. In addition to the characteristic change of regioselectivity, the reversal of absolute configuration as a function of reaction temperature was also observed.
Ligand-metal cooperating PC(sp3)P pincer complexes as catalysts in olefin hydroformylation
Musa, Sanaa,Filippov, Oleg A.,Belkova, Natalia V.,Shubina, Elena S.,Silantyev, Gleb A.,Ackermann, Lutz,Gelman, Dmitri
supporting information, p. 16906 - 16909 (2014/01/06)
Ligand-metal cooperation: A new ligand-metal cooperating catalyst for the hydroformylation of olefins is described (see scheme). The mechanism of the H2 activation and C-H bond formation of the catalyst involves an intramolecular cooperation between the structurally remote functionality and the metal center and proceeds without change of the oxidation state of the metal.
Effective construction of quaternary stereocenters by highly enantioselective α-amination of branched aldehydes
Fu, Ji-Ya,Xu, Xiao-Ying,Li, Yan-Chun,Huang, Qing-Chun,Wang, Li-Xin
supporting information; experimental part, p. 4524 - 4526 (2010/11/21)
A highly efficient enantioselective α-amination of branched aldehydes with azadicarboxylates promoted by chiral proline-derived amide thiourea bifunctional catalysts was developed for the first time, affording the adducts bearing quaternary stereogenic centers with excellent yields (up to 99%) and enantioselectivities (up to 97% ee).
Highly selective hydroformylation of vinylarenes to branched aldehydes by [Rh(cod)Cl]2 entrapped in ionic liquid modified silica sol-gel
Hamza, Khalil,Blum, Jochanan
, p. 4706 - 4710 (2008/03/13)
A co-entrapped mixture of [Rh(cod)Cl]2 and Na[Ph 2P-3-(C6H4SO3)] within a silica sol-gel matrix modified with ca. 5% of 1-butyl-3-[3-(trimethoxysilyl)propyl] imidazolium chloride catalyzes, in n-heptane, the hydroformylation of a variety of vinylarenes. At 50°C and under 6.9 bar each of H2 and CO the reaction is high-yielding and highly selective. Non-hindered substrates give >95 % of branched aldehydes and only 5% of the linear isomers. The ceramic catalyst is leach-proof and recyclable. It does not lose its high catalytic activity and selectivity for at least four runs. The selectivity depends on the pressure of the gases, the temperature and the solvent. The electronic nature has no influence on the selectivity, but the latter is diminished by steric effects. Upon omission of the sol-gel component, the catalyst deteriorates and practically loses its activity after the first half-life of the reaction. In the absence of the ionic liquid, the catalyst undergoes substantial leaching. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
