80793-24-4Relevant articles and documents
Synthesis of rac-ɑ-aryl propionaldehydes via branched-selective hydroformylation of terminal arylalkenes using water-soluble Rh-PNP catalyst
Chen, Fen-Er,Gao, Peng,Ke, Miaolin,Liang, Guanfeng,Ru, Tong
, (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.
Complex Polyheterocycles and the Stereochemical Reassignment of Pileamartine A via Aza-Heck Triggered Aryl C-H Functionalization Cascades
Bower, John F.,Caiger, Lewis,García-Cárceles, Javier,Hazelden, Ian R.,Jones, Benjamin T.,Langer, Thomas,Lewis, Richard J.
, p. 15593 - 15598 (2021/10/12)
Structurally complex benzo- and spiro-fused N-polyheterocycles can be accessed via intramolecular Pd(0)-catalyzed alkene 1,2-aminoarylation reactions. The method uses N-(pentafluorobenzoyloxy)carbamates as the initiating motif, and this allows aza-Heck-type alkene amino-palladation in advance of C-H palladation of the aromatic component. The chemistry is showcased in the first total synthesis of the complex alkaloid (+)-pileamartine A, which has resulted in the reassignment of its absolute stereochemistry.
Transfer hydrogenations catalyzed by streptavidin-hosted secondary amine organocatalysts
Santi, Nicolò,Morrill, Louis C.,?widerek, Katarzyna,Moliner, Vicent,Luk, Louis Y. P.
supporting information, p. 1919 - 1922 (2021/03/02)
Here, the streptavidin-biotin technology was applied to enable organocatalytic transfer hydrogenation. By introducing a biotin-tethered pyrrolidine (1) to the tetrameric streptavidin (T-Sav), the resulting hybrid catalyst was able to mediate hydride transfer from dihydro-benzylnicotinamide (BNAH) to α,β-unsaturated aldehydes. Hydrogenation of cinnamaldehyde and some of its aryl-substituted analogues was found to be nearly quantitative. Kinetic measurements revealed that the T-Sav:1 assembly possesses enzyme-like behavior, whereas isotope effect analysis, performed by QM/MM simulations, illustrated that the step of hydride transfer is at least partially rate-limiting. These results have proven the concept thatT-Savcan be used to host secondary amine-catalyzed transfer hydrogenations.
Cucurbiturils Monofunctionalized on the Methylene Bridge and Their Host-Guest Properties
Kandrnálová, Markéta,?indelá?, Vladimír
supporting information, p. 4733 - 4736 (2021/09/10)
Monofunctionalization of cucurbiturils is essential for transferring these potent supramolecular macrocyclic hosts into real-world application. Here, we present the synthesis of cucurbit[6]urils 1 and 2 in which one methylene bridge is modified by a single substituent containing a nitro or an ammonium group. We investigated host–guest properties in water and 0.2 M NaCl using 1H?NMR and isothermal titration calorimetry, particularly for 2. The macrocycle 2 self-associated into dimeric aggregates in pure water, but readily disassembled in the presence of NaCl or organic cations. Cucurbit[7]uril was able to encapsulate the ammonium substituent of 2 inside its cavity resulting in a complex of 1 : 1 stoichiometry with an association constant of 3.1×105 M?1. The presented host–guest properties together with further possible derivatization showcase the potential of cucurbiturils modified in the methylene position such as 1 and 2 for the development of advanced supramolecular systems.
Heck arylation of allyl alcohol catalyzed by Pd(0) nanoparticles
Tarnowicz, Stanis?awa,Alsalahi, Waleed,Mieczyńska, Ewa,Trzeciak, Anna M.
, p. 5605 - 5612 (2017/08/26)
Pd(0) nanoparticles ca. 2 nm in diameter were obtained by the reduction of PdCl2 and Pd(OAc)2 in water at 80 °C in the presence of a PVP-stabilizing polymer. Pd(0) NPs were successfully used in the Heck coupling of allyl alcohol with iodo- and bromobenzenes. Iodobenzenes reacted under solventless conditions or in DMF solution producing 3-arylpropanals and 2-arylpropanals as the main products. The same products were obtained in the reaction of bromobenzene in TBAB as the reaction medium. The stability of Pd(0) NPs was evidenced in recycling experiments. Similar Heck coupling results were also obtained with the palladium compounds PdCl2(cod) and Pd(OAc)2 under the same conditions.
Surface bonded Rh-bis(diarylphosphine) on magnetic nanoparticles as a recyclable catalyst for hydroformylation of olefins
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Page/Page column 23-24, (2016/11/21)
A functionalized nanomaterial having an average particles size of less than 10 nm comprising an iron oxide nanoparticle core and a bis(diarylphosphinomethyl) dopamine based ligand layer anchored to the iron oxide nanoparticle core is disclosed. In addition, a catalyst composition for use in a variety of chemical transformations wherein the bisphosphine groups of the functionalized nanomaterial chelate a catalytic metal is disclosed. In addition, a method for producing the functionalized nanomaterial and a method for the hydroformylation of olefins to aldehydes employing the functionalized nanomaterial with high conversion percentage and high selectivity are disclosed.
Scope and mechanism in palladium-catalyzed isomerizations of highly substituted allylic, homoallylic, and alkenyl alcohols
Larionov, Evgeny,Lin, Luqing,Gune, Laure,Mazet, Clment
supporting information, p. 16882 - 16894 (2015/01/09)
Herein we report the palladium-catalyzed isomerization of highly substituted allylic alcohols and alkenyl alcohols by means of a single catalytic system. The operationally simple reaction protocol is applicable to a broad range of substrates and displays a wide functional group tolerance, and the products are usually isolated in high chemical yield. Experimental and computational mechanistic investigations provide complementary and converging evidence for a chain-walking process consisting of repeated migratory insertion/β-H elimination sequences. Interestingly, the catalyst does not dissociate from the substrate in the isomerization of allylic alcohols, whereas it disengages during the isomerization of alkenyl alcohols when additional substituents are present on the alkyl chain.
How phenyl makes a difference: Mechanistic insights into the ruthenium(ii)-catalysed isomerisation of allylic alcohols
Manzini, Simone,Poater, Albert,Nelson, David J.,Cavallo, Luigi,Nolan, Steven P.
, p. 180 - 188 (2014/01/06)
[RuCl(η5-3-phenylindenyl)(PPh3)2] (1) has been shown to be a highly active catalyst for the isomerisation of allylic alcohols to the corresponding ketones. A variety of substrates undergo the transformation, typically with 0.25-0.5 mol% of catalyst at room temperature, outperforming commonly-used complexes such as [RuCl(Cp)(PPh3) 2] and [RuCl(η5-indenyl)(PPh3) 2]. Mechanistic experiments and density functional theory have been employed to investigate the mechanism and understand the effect of catalyst structure on reactivity. These investigations suggest a oxo-π-allyl mechanism is in operation, avoiding intermediate ruthenium hydride complexes and leading to a characteristic 1,3-deuterium shift. Important mechanistic insights from DFT and experiments also allowed for the design of a protocol that expands the scope of the transformation to include primary allylic alcohols.
3,5-Disubstituted-thiazolidine-2,4-dione analogs as anticancer agents: Design, synthesis and biological characterization
Liu, Kai,Rao, Wei,Parikh, Hardik,Li, Qianbin,Guo, Tai L.,Grant, Steven,Kellogg, Glen E.,Zhang, Shijun
experimental part, p. 125 - 137 (2012/03/08)
A series of 2,5-disubstituted-thiazolidine-2,4-dione analogs based on the newly identified lead 1, a potential anticancer agent via the inhibition of the Raf/MEK/extracellular signal regulated kinase (ERK) and phosphatidylinositol 3-kinase (PI3K)/Akt signaling cascades, were synthesized and biologically characterized. A new lead structure, 15, was identified to have improved anti-proliferative activities in U937 cells, to induce apoptosis in U937, M12 and DU145 cancer cells, and to arrest U937 cells at the S-phase. Furthermore, Western blot analysis demonstrated a correlation of the anti-proliferative activity and blockade of the Raf/MEK/ERK and PI3K/Akt signaling pathways. Collectively, these results strongly encourage further optimization of 15 as a new lead with multi-target properties to develop more potent compounds as anticancer agents.
Pd-catalyzed cascade Heck-Saegusa: Direct synthesis of enals from aryl iodides and allyl alcohol
Liu, Jie,Zhu, Jin,Jiang, Hualiang,Wang, Wei,Li, Jian
supporting information; experimental part, p. 415 - 417 (2010/04/04)
A new efficient Pd-catalyzed cascade Heck-Saegusa protocol for the synthesis of synthetically useful α,β-unsaturated aldehydes in high yields from readily available aryl iodides and allyl alcohol has been developed.
