cas 20401-88-1, 3-(4-METHOXY-PHENYL)-PROPIONALDEHYDE

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Conjugate addition of electron-rich aromatics to acrolein in the confined space of zeolite Y
Acrolein gas was spontaneously entrapped in supercages of NaY zeolite and the sorption was confirmed by solid 13C MAS NMR spectra. In the confined cavities, acrolein smoothly underwent conjugate addition with electron-rich aromatics such as ind
Imachi, Shouhei,Onaka, Makoto
p. 708 - 709
(2005)
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Asymmetric Multifunctional Modular Organocatalysis: One-Pot Direct Strategy to Enantiopure α,β-Disubstituted γ-Butyrolactones
A simple and efficient approach to enantioenriched α,β-disubstituted γ-butyrolactones has been developed through multifunctional modular organocatalysis in a highly enantioselective (>99% ee) and diastereoselective (>30:1) manner following a one-pot sequential Michael-hemiacetalization-oxidation reaction. The catalytic process has great substrate compatibility, and the products have been transformed to synthetically useful molecules. The methodology has also been applied to the formal synthesis of (+)-Pilocarpine.
Mahto, Pratibha,Rana, Nirmal K.,Shukla, Khyati,Das, Braja G.,Joshi, Harshit,Singh, Vinod K.
p. 5962 - 5966
(2019)
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Magnetic nanoparticles as a catalyst vehicle for simple and easy recycling
The surface of magnetic ferrite nanoparticles (CoFe2O4) was coated with a Rh-based cationic complex, [Rh(cod)(η6-benzoic acid)]BF4, to make them homogeneously dispersable and thermodynamically stable without an
Yoon, Tae-Jong,Lee, Woo,Oh, Yoon-Seuk,Lee, Jin-Kyu
p. 227 - 229
(2003)
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A practical procedure for the synthesis of multifunctional aldehydes through the Fukuyama reduction and elucidation of the reaction site and mechanism
A highly efficient heterogeneous Pd/C catalyst D1 was found to effect the reduction of thiol esters 1 to the corresponding aldehydes 2 with such a low catalyst loading as 0.5-1.0mol%. The chemical properties of the Pd/C catalysts together with the XRF analysis reveal that the reduction is most likely to proceed on the solid surface of the Pd/C catalyst rather than in the solution phase outside the pores. A reaction mechanism through oxidative addition of Pd to the thiol esters 1 was postulated by detection of the oxidative addition intermediate by React IR analysis. A practical purification of 2 was accomplished by conversion to water-soluble bisulfite adducts 7.
Kimura, Mayumi,Seki, Masahiko
p. 3219 - 3223
(2004)
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The first one-pot metathesis-hydroformylation procedure: a straight synthesis of 2-arylpropanals from renewable 1-propenylbenzenes
Hydroformylation is a consolidated synthetic tool in the chemical industry, both in commodity and in the fine chemicals industry. Olefin metathesis has been largely employed in the petrochemical sector, and, more recently, in the synthesis of specialty chemicals. Although these reactions may be involved in the same synthetic route for various industrial chemicals, to the best of our knowledge, they have never been combined in a one-pot procedure. As a proof of concept, we have demonstrated in the present work that the ruthenium-catalyzed ethenolysis of renewable 1-propenylbenzenes followed by the rhodium-catalyzed hydroformylation of functionalized styrenes formed in the first step could be done in one pot. The integration of these reactions was not straightforward once the catalyst of the first step interfered with the catalyst of the second step. Under optimized conditions, it was possible to synthesize 2-arylpropanals, a class of compounds valuable as synthetic intermediates to access non-steroidal anti-inflammatory drugs, in overall yields of 85-90%, at low catalyst loadings.
Avenda?o Villarreal, Jesus Alberto,Delolo, Fábio Godoy,Granato, Artur Vicari,Gusevskaya, Elena Vitalievna,dos Santos, Eduardo Nicolau
p. 8007 - 8013
(2021/12/27)

Transfer hydrogenations catalyzed by streptavidin-hosted secondary amine organocatalysts
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.
Santi, Nicolò,Morrill, Louis C.,?widerek, Katarzyna,Moliner, Vicent,Luk, Louis Y. P.
supporting information
p. 1919 - 1922
(2021/03/02)

Catalytic δ-hydroxyalkynone rearrangement in the stereoselective total synthesis of centrolobine, engelheptanoxides A and C and analogues
A catalytic stereoselective total synthesis of centrolobine and engelheptanoxides A and C has been completed via a metal-free catalytic δ-hydroxyalkynone rearrangement to 2,3-dihydro-4H-pyran-4-one and diastereoselective hydrogenation to the all syn-2,4,6-trisubstituted pyran strategy. The onliest required chirality was introduced by Jacobsen kinetic resolution, which further directed the diastereoselective hydrogenation. A first stereoselective synthesis of engelheptanoxide A is also accomplished. The analogues and derivatives of centrolobine and engelheptanoxides prepared were evaluated for antitubercular activity against M. tuberculosis H37Rv ATCC 27294.
Ahmad, Mohammad N.,Chopra, Sidharth,Fernandes, Rodney A.,Kumar, Praveen
(2021/08/13)

Access to Trisubstituted Fluoroalkenes by Ruthenium-Catalyzed Cross-Metathesis
Although the olefin metathesis reaction is a well-known and powerful strategy to get alkenes, this reaction remained highly challenging with fluororalkenes, especially the Cross-Metathesis (CM) process. Our thought was to find an easy accessible, convenient, reactive and post-functionalizable source of fluoroalkene, that we found as the methyl 2-fluoroacrylate. We reported herein the efficient ruthenium-catalyzed CM reaction of various terminal and internal alkenes with methyl 2-fluoroacrylate giving access, for the first time, to trisubstituted fluoroalkenes stereoselectively. Unprecedent TON for CM involving fluoroalkene, up to 175, have been obtained and the reaction proved to be tolerant and effective with a large range of olefin partners giving fair to high yields in metathesis products. (Figure presented.).
Nouaille, Augustin,Pannecoucke, Xavier,Poisson, Thomas,Couve-Bonnaire, Samuel
p. 2140 - 2147
(2021/03/06)

Complex Polyheterocycles and the Stereochemical Reassignment of Pileamartine A via Aza-Heck Triggered Aryl C-H Functionalization Cascades
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.
Bower, John F.,Caiger, Lewis,García-Cárceles, Javier,Hazelden, Ian R.,Jones, Benjamin T.,Langer, Thomas,Lewis, Richard J.
supporting information
p. 15593 - 15598
(2021/10/12)

Synthesis of rac-ɑ-aryl propionaldehydes via branched-selective hydroformylation of terminal arylalkenes using water-soluble Rh-PNP catalyst
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.
Chen, Fen-Er,Gao, Peng,Ke, Miaolin,Liang, Guanfeng,Ru, Tong
(2021/08/26)

Chemo- And regioselective hydroformylation of alkenes with CO2/H2over a bifunctional catalyst
As is well known, CO2 is an attractive renewable C1 resource and H2 is a cheap and clean reductant. Combining CO2 and H2 to prepare building blocks for high-value-added products is an attractive yet challenging topic in green chemistry. A general and selective rhodium-catalyzed hydroformylation of alkenes using CO2/H2 as a syngas surrogate is described here. With this protocol, the desired aldehydes can be obtained in up to 97% yield with 93/7 regioselectivity under mild reaction conditions (25 bar and 80 °C). The key to success is the use of a bifunctional Rh/PTA catalyst (PTA: 1,3,5-triaza-7-phosphaadamantane), which facilitates both CO2 hydrogenation and hydroformylation. Notably, monodentate PTA exhibited better activity and regioselectivity than common bidentate ligands, which might be ascribed to its built-in basic site and tris-chelated mode. Mechanistic studies indicate that the transformation proceeds through cascade steps, involving free HCOOH production through CO2 hydrogenation, fast release of CO, and rhodium-catalyzed conventional hydroformylation. Moreover, the unconventional hydroformylation pathway, in which HCOOAc acts as a direct C1 source, has also been proved to be feasible with superior regioselectivity to that of the CO pathway.
Hua, Kaimin,Liu, Xiaofang,Wei, Baiyin,Shao, Zilong,Deng, Yuchao,Zhong, Liangshu,Wang, Hui,Sun, Yuhan
supporting information
p. 8040 - 8046
(2021/11/01)

Insight into decomposition of formic acid to syngas required for Rh-catalyzed hydroformylation of olefins
Formic acid (FA) is one kind of important bulk chemicals, which is recognized as a sustainable and eco-friendly energy carrier to transport H2 via dehydrogenation or CO via decarbonylation. Expectantly, FA upon decomposition into H2 and CO could be used as the syngas alternative for hydroformylation. In this paper, the behaviors of FA to release H2 as well as CO following the distinct pathways were carefully investigated for the first time, and then established a new hydroformylation protocol free of syngas. It was found that the atmospheric hydroformylation of olefins with formic acid (FA) as syngas alternative was smoothly fulfilled over Xantphos (L1) modified Rh-catalyst under mild conditions (80 °C, Rh concentration 1 mol %, 14 h), resulting in >90% conversion of the olefins along with the high selectivity to the target aldehydes (>93%). By using FA as syngas source, the side-reaction of olefin-hydrogenation was greatly depressed. The in situ FT-IR and the high-pressure 1H NMR spectroscopic analyses were applied to reveal how FA behaves dually as CO surrogate and hydrogen source over L1-Rh(acac)(CO)2 catalytic system, based on which the deeply insight into the catalytic mechanism of hydroformylation of olefins with FA as syngas alternative was offered.
Liu, Lei,Chen, Xiao-Chao,Yang, Shu-Qing,Yao, Yin-Qing,Lu, Yong,Liu, Ye
p. 406 - 415
(2020/12/07)

Silicon Carbide Supported Palladium-Iridium Bimetallic Catalysts for Efficient Selective Hydrogenation of Cinnamaldehyde
Selective hydrogenation of α,β-unsaturated carbonyls into saturated carbonyls is important to obtain remunerative products. However, it is still a challenge to achieve high activity and selectivity under mild conditions. Herein, Pd, Ir and bimetallic Pd-Ir nanoparticles were uniformly deposited with high dispersity on the surface of SiC by a facile impregnation method, respectively. The as-prepared Pd/SiC catalysts efficiently hydrogenate cinnamaldehyde to hydrocinnamaldehyde at room temperature and atmospheric pressure, and the activity of Pd/SiC is observed further enhanced by adding Ir component (conversion of 100%). In addition, the dependence of Pd-Ir catalyst activity on Pd/Ir molar ratio confirms a synergistic effect between Ir and Pd, which originates from the electron transfer between Pd and Ir.
Guo, Xiang-Yun,Jin, Guoqiang,Li, Penghui,Tong, Xili,Wang, Yingyong,Wang, Yunwei
(2020/02/25)

Chemoselective hydrogenation of α,β-unsaturated aldehydes over Rh nanoclusters confined in a metal-organic framework
Selective hydrogenation of α,β-unsaturated aldehydes to achieve high selectivity towards a desirable product is still a great challenge mainly because of the complex conjugate system. Herein, Rh nanoclusters encapsulated in MIL-101 (Cr), synthesized by the double solvent method, are able to selectively hydrogenate C-C of cinnamaldehyde, an α,β-unsaturated aldehyde and achieve over 98percent selectivity with a conversion of 98percent to a saturated aldehyde under mild conditions. Fourier transform infrared spectroscopy confirms that MIL-101 acts as an aldehyde protector to suppress the reactivity of C-O, and the X-ray photoelectron spectroscopy (XPS) data indicate that the electropositive Rh, owing to the electron transfer from Rh to MIL-101, preferentially absorbs C-C rather than C-O leading to -improvement of the selectivity towards saturated aldehydes. In addition, Rh@MIL-101 can also efficiently catalyse hydrodefluorination of aryl fluorides with good stability. This work provides a basic strategy to develop other selective heterogeneous catalystsviastructural modulation for synergetic catalysis.
Liu, Qinglin,Li, Yinle,Fan, Yanan,Su, Cheng-Yong,Li, Guangqin
p. 11442 - 11447
(2020/06/29)

Transition-Metal-Free Synthesis of Electron Rich 1,3-Dienes via Base Promoted Isomerization of Propargylic Ethers
Herein, a novel and scalable synthesis of electron rich 1,3-dienes based on KOtBu mediated isomerization of propargylic ether derivatives was developed. This new process features easy handling reaction conditions, transition-metal-free isomerization, high isolated yields, and most of all, it could be used for modification of natural products at late stage functionalizations.
Liu, Chunxiang,Deng, Guogang,Li, Xin,Xu, Yiren,Yu, Kaili,Chen, Wen,Zhang, Hongbin,Yang, Xiaodong
supporting information
p. 483 - 487
(2020/01/25)

Triphenylphosphine-Based Covalent Organic Frameworks and Heterogeneous Rh-P-COFs Catalysts
The synthesis of phosphine-based functional covalent organic frameworks (COFs) has attracted great attention recently. Herein, we present two examples of triphenylphosphine-based COFs (termed P-COFs) with well-defined crystalline structures, high specific surface areas, and good thermal stability. Furthermore, rhodium catalysts with these P-COFs as support material show high turnover frequency for the hydroformylation of olefins, as well as excellent recycling performance. This work not only extends the phosphine-based COF family, but also demonstrates their application in immobilizing homogeneous metal-based (e.g., Rh-phosphine) catalysts for application in heterogeneous catalysis.
Liu, Yubing,Dikhtiarenko, Alla,Xu, Naizhang,Sun, Jiawei,Tang, Jie,Wang, Kaiqiang,Xu, Bolian,Tong, Qing,Heeres, Hero Jan,He, Songbo,Gascon, Jorge,Fan, Yining
supporting information
p. 12134 - 12139
(2020/09/01)

Binuclear Pd(I)-Pd(I) Catalysis Assisted by Iodide Ligands for Selective Hydroformylation of Alkenes and Alkynes
Since its discovery in 1938, hydroformylation has been thoroughly investigated and broadly applied in industry (>107 metric ton yearly). However, the ability to precisely control its regioselectivity with well-established Rh- or Co-catalysts has thus far proven elusive, thereby limiting access to many synthetically valuable aldehydes. Pd-catalysts represent an appealing alternative, yet their use remains sparse due to undesired side-processes. Here, we report a highly selective and exceptionally active catalyst system that is driven by a novel activation strategy and features a unique Pd(I)-Pd(I) mechanism, involving an iodide-assisted binuclear step to release the product. This method enables β-selective hydroformylation of a large range of alkenes and alkynes, including sensitive starting materials. Its utility is demonstrated in the synthesis of antiobesity drug Rimonabant and anti-HIV agent PNU-32945. In a broader context, the new mechanistic understanding enables the development of other carbonylation reactions of high importance to chemical industry.
Zhang, Yang,Torker, Sebastian,Sigrist, Michel,Bregovi?, Nikola,Dydio, Pawe?
supporting information
p. 18251 - 18265
(2020/11/02)

Iodine-catalyzed α,β-dehydrogenation of ketones and aldehydes generating conjugated enones and enals
A transition metal-free α,β-dehydrogenation of ketones and aldehydes was developed. This reaction was conducted in a facile I2/KI/DMSO system to produce the corresponding unsaturated compounds in good to high yields. The gram-scale experiment also indicated the potential synthetic value of this new reaction in organic synthesis. In the reaction, DMSO acted as both solvent and mild oxidant.
Cao, Yuanjie,Chen, Tieqiao,Huang, Tianzeng,Liu, Long
supporting information
p. 8697 - 8701
(2020/06/08)

Diaza-Crown Ether-Bridged Chiral Diphosphoramidite Ligands: Synthesis and Applications in Asymmetric Catalysis
A small library of diaza-crown ether-bridged chiral diphosphoramidite ligands was prepared. In the rhodium-catalyzed asymmetric hydrogenation and hydroformylation reactions, these ligands exhibited distinct properties in catalytic activity and/or enantioselectivity. Hydrogenated products with opposite absolute configurations could be obtained in high yields with excellent ee values by utilizing (S,S)-L1 and (S,S)-L3, respectively. Meanwhile, the addition of alkali metal cations caused variations in catalytic outcomes, showing the supramolecular tunability of these Rh/diphosphoramidite catalytic systems.
Luo, Yier,Ouyang, Guanghui,Tang, Yuping,He, Yan-Mei,Fan, Qing-Hua
p. 8176 - 8184
(2020/07/15)

Tandem IBX-Promoted Primary Alcohol Oxidation/Opening of Intermediate β,γ-Diolcarbonate Aldehydes to (E)-γ-Hydroxy-α,β-enals
A tandem IBX-promoted oxidation of primary alcohol to aldehyde and opening of intermediate β,γ-diolcarbonate aldehyde to (E)-γ-hydroxy-α,β-enal has been developed. Remarkably, the carbonate opening delivered exclusively (E)-olefin and no over-oxidation of γ-hydroxy was observed. The method developed has been extended to complete the stereoselective total synthesis of both (S)- and (R)-coriolides and d-xylo- and d-arabino-C-20 guggultetrols.
Kumari, Anupama,Gholap, Sachin P.,Fernandes, Rodney A.
p. 2278 - 2290
(2019/06/17)

Diastereoselective peroxidation of derivatives of Baylis–Hillman adducts
Cyclic derivatives of Baylis–Hillman adducts were synthesized. Cobalt-catalyzed peroxidation of these cyclic lactones afforded silyl peroxides in diastereomeric ratios ranging from 91:9 to 97:3.
Zuckerman, Dylan S.,Woerpel
supporting information
p. 4118 - 4129
(2019/06/24)

Heterocyclization involving benzylic C(sp3)-H functionalization enabled by visible light photoredox catalysis
A general and efficient method for heterocyclization involving benzylic C(sp3)-H functionalization enabled by visible light photoredox catalysis to access a wide range of structurally diverse oxygen as well as nitrogen heterocycles up to a gram scale is reported. The potential application of this new methodology is demonstrated by the total synthesis of (-)-codonopsinine and (+)-centrolobine. Herein it is proposed that selectfluor, unlike a fluorinating reagent, acts as an oxidative quencher and a hydrogen radical acceptor.
Pandey, Ganesh,Laha, Ramkrishna,Mondal, Pradip Kumar
supporting information
p. 9689 - 9692
(2019/08/15)

Remote Functionalization of α,β-Unsaturated Carbonyls by Multimetallic Sequential Catalysis
The remote functionalization of α,β-unsaturated carbonyls by an array of multimetallic sequential catalytic systems is described. The reactions are triggered by hydrometalation using [Pd-H] or [Ru-H] isomerization catalysts and driven by the formation of thermodynamically more stable 1,2-vinyl arenes. The Pd-catalyzed deconjugative isomerization was combined with a Cu-catalyzed β-borylation of the transiently generated styrenyl derivatives to deliver a range of products that would not be accessible with the use of a single catalyst. [Pd/Cu] catalytic systems were also identified for the highly enantioselective α-hydroboration and α-hydroamination of the styrenyl intermediates. Difunctionalization simultaneously at the benzylic and homobenzylic positions was achieved by combining the isomerization process with Sharpless asymmetric dihydroxylation (SAD) using [Pd/Os] or [Ru/Os] couples. Starting from a simple α,β-unsaturated ester, an isomerization/dihydroxylation/lactonization sequence gave access to a naturally occurring γ-butyrolactone in good yield, with excellent diastereo- and enantioselectivity.
Romano, Ciro,Fiorito, Daniele,Mazet, Clément
supporting information
p. 16983 - 16990
(2019/10/28)

Carbene-Catalyzed α-Carbon Amination of Chloroaldehydes for Enantioselective Access to Dihydroquinoxaline Derivatives
An NHC-catalyzed α-carbon amination of chloroaldehydes was developed. Cyclohexadiene-1,2-diimines are used as amination reagents and four-atom synthons. Our reaction affords optically enriched dihydroquinoxalines that are core structures in natural products and synthetic bioactive molecules.
Huang, Ruoyan,Chen, Xingkuan,Mou, Chengli,Luo, Guoyong,Li, Yongjia,Li, Xiangyang,Xue, Wei,Jin, Zhichao,Chi, Yonggui Robin
p. 4340 - 4344
(2019/06/14)

MICROCAPSULES AND PROCESSES FOR THEIR PREPARATION
The present invention provides microcapsules encapsulating hydrophilic or hydrophobic active agents in an inorganic shell, processes for their preparation and compositions comprising them.
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(2019/06/11)

Synthesis of tetra-pincer nickel(ii) and palladium(ii) complexes of resorcin[4]arene-octophosphinite [Res(OPR2)8] and rhodium-catalyzed regioselective hydroformylation reaction
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.
Ananthnag, Guddekoppa S.,Mondal, Dipanjan,Mague, Joel T.,Balakrishna, Maravanji S.
p. 14632 - 14641
(2019/10/16)

Introduction of Cyclopropyl and Cyclobutyl Ring on Alkyl Iodides through Cobalt-Catalyzed Cross-Coupling
A cobalt-catalyzed cross-coupling between alkyl iodides and cyclopropyl, cyclobutyl, and alkenyl Grignard reagents is disclosed. The reaction allows the introduction of strained rings on a large panel of primary and secondary alkyl iodides. The catalytic system is simple and nonexpensive, and the reaction is general, chemoselective, and diastereoconvergent. The alkene resulting from the cross-coupling can be transformed to substituted cyclopropanes using a Simmons-Smith reaction. The formation of radical intermediates during the coupling is hypothesized.
Andersen, Claire,Ferey, Vincent,Daumas, Marc,Bernardelli, Patrick,Guérinot, Amandine,Cossy, Janine
supporting information
p. 2285 - 2289
(2019/03/29)

Rhodium-Catalyzed Parallel Kinetic Resolution of Racemic Internal Allenes Towards Enantiopure Allylic 1,3-Diketones
A rare case of a parallel kinetic resolution of racemic 1,3-disubstituted allenes by means of a rhodium-catalyzed addition to 1,3-diketones furnishing enantiopure allylic 1,3-diketones is described. Mechanistic experiments demonstrate that the different allene enantiomers react in parallel to either the diastereomeric E- or Z-allylic 1,3-diketones with the same absolute configuration of the newly formed stereogenic center. A broad substrate scope demonstrates the synthetic utility of this new method.
Hilpert, Lukas J.,Breit, Bernhard
supporting information
p. 9939 - 9943
(2019/06/24)

A Nucleophilicity Scale for the Reactivity of Diazaphospholenium Hydrides: Structural Insights and Synthetic Applications
Nucleophilicity parameters (N, sN) of a group of representative diazaphospholenium hydrides were derived by kinetic investigations of their hydride transfer to a series of reference electrophiles with known electrophilicity (E) values, using the Mayr equation log k2=sN(N+E). The N scale covers over ten N units, ranging from the most reactive hydride donor (N=25.5) to the least of the scale (N=13.5). This discloses the highest N value ever quantified in terms of Mayr's nucleophilicity scales reported for neutral transition-metal-free hydride donors and implies an exceptional reactivity of this reagent. Even the least reactive hydride donor of this series is still a better hydride donor than those of many other nucleophiles such as the C?H, B?H, Si?H and transition-metal M?H hydride donors. Structure–reactivity analysis reveals that the outstanding hydricity of 2-H-1,3,2-diazaphospholene benefits from the unsaturated skeleton.
Zhang, Jingjing,Yang, Jin-Dong,Cheng, Jin-Pei
supporting information
p. 5983 - 5987
(2019/04/03)

Synthesis, in vitro and in silico evaluation of diaryl heptanones as potential 5LOX enzyme inhibitors
A new series of diaryl heptanones (12a-q) were synthesized and their structures were confirmed by its 1H, 13C NMR and Mass spectral data. These analogs were evaluated for their anti-oxidant activity and potential to inhibit 5-lipoxygenase. Compounds 12k and 12o showed potent in vitro 5-lipoxygenase enzyme inhibitory activity with IC50 values of 22.2, 21.5 μM, which are comparable to curcumin (24.4 μM). Further they also have shown significant antioxidant activity. Molecular docking studies clearly showed correlation between binding energy and potency of these compounds.
Meka, Bharani,Ravada, Suryachandra Rao,Muthyala, Murali Krishna Kumar,Kurre, Purna Nagasree,Golakoti, Trimurtulu
p. 408 - 421
(2018/07/13)

Direct Access to N-tert-Butanesulfinyl Imines from Aryl Iodides, Alkenyl Alcohols, and N-tert-Butanesulfinamide
The reaction of aryl iodides, N-tert-butanesulfinamide, and allyl or homoallyl alcohol in the presence of a catalytic amount of Pd(OAc)2, NaHCO3 as a base, and TBAB leads to the formation of N-tert-butanesulfinyl imines in moderate yields. In this one-pot process, a sequential Heck-type arylation of the alkenol, isomerization of the double bond, and imine formation take place.
Ikhlef, Sofiane,Behloul, Cherif,Lahosa, Alejandro,Foubelo, Francisco,Yus, Miguel
p. 2609 - 2614
(2018/05/03)

Iron Catalyzed Hydroformylation of Alkenes under Mild Conditions: Evidence of an Fe(II) Catalyzed Process
Earth abundant, first row transition metals offer a cheap and sustainable alternative to the rare and precious metals. However, utilization of first row metals in catalysis requires harsh reaction conditions, suffers from limited activity, and fails to tolerate functional groups. Reported here is a highly efficient iron catalyzed hydroformylation of alkenes under mild conditions. This protocol operates at 10-30 bar syngas pressure below 100 °C, utilizes readily available ligands, and applies to an array of olefins. Thus, the iron precursor [HFe(CO)4]-[Ph3PNPPh3]+ (1) in the presence of triphenyl phosphine catalyzes the hydroformylation of 1-hexene (S2), 1-octene (S1), 1-decene (S3), 1-dodecene (S4), 1-octadecene (S5), trimethoxy(vinyl)silane (S6), trimethyl(vinyl)silane (S7), cardanol (S8), 2,3-dihydrofuran (S9), allyl malonic acid (S10), styrene (S11), 4-methylstyrene (S12), 4-iBu-styrene (S13), 4-tBu-styrene (S14), 4-methoxy styrene (S15), 4-acetoxy styrene (S16), 4-bromo styrene (S17), 4-chloro styrene (S18), 4-vinylbenzonitrile (S19), 4-vinylbenzoic acid (S20), and allyl benzene (S21) to corresponding aldehydes in good to excellent yields. Both electron donating and electron withdrawing substituents could be tolerated and excellent conversions were obtained for S11-S20. Remarkably, the addition of 1 mol % acetic acid promotes the reaction to completion within 16-24 h. Detailed mechanistic investigations revealed in situ formation of an iron-dihydride complex [H2Fe(CO)2(PPh3)2] (A) as an active catalytic species. This finding was further supported by cyclic voltammetry investigations and intermediacy of an Fe(0)-Fe(II) species was established. Combined experimental and computational investigations support the existence of an iron-dihydride as the catalyst resting state, which then follows a Fe(II) based catalytic cycle to produce aldehyde.
Pandey, Swechchha,Raj, K. Vipin,Shinde, Dinesh R.,Vanka, Kumar,Kashyap, Varchaswal,Kurungot, Sreekumar,Vinod,Chikkali, Samir H.
supporting information
p. 4430 - 4439
(2018/04/05)

FUNCTIONALIZED MAGNETIC NANOPARTICLE, A CATALYST, A METHOD FOR FORMING C-C BONDS
A functionalized magnetic nanoparticle including an organometallic sandwich compound and a magnetic metal oxide. The functionalized magnetic nanoparticle may be reacted with a metal precursor to form a catalyst for various C—C bond forming reactions. The catalyst may be recovered with ease by attracting the catalyst with a magnet.
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Paragraph 0210

(2018/04/20)

Synthesis and in vitro antiproliferative activity of C5-benzyl substituted 2-amino-pyrrolo[2,3-d]pyrimidines as potent Hsp90 inhibitors
A novel series of heat shock protein 90 (Hsp90) inhibitors was identified by X-ray crystal analysis of complex structures at solvent-exposed exit pocket C. The 2-amino-pyrrolo[2,3-d]pyrimidine derivatives, 7-deazapurines substituted with a benzyl moiety at C5, showed potent Hsp90 inhibition and broad-spectrum antiproliferative activity against NCI-60 cancer cell lines. The most potent compound, 6a, inhibited Hsp90 with an IC50of 36?nM and showed a submicromolar mean GI50value against NCI-60 cell lines. The interaction of 6a at the ATP-binding pocket of Hsp90 was confirmed by X-ray crystallography and Western blot analysis.
Lee, Ju-Hyeon,Shin, Sang Chul,Seo, Seon Hee,Seo, Young Ho,Jeong, Nakcheol,Kim, Chan-Wha,Kim, Eunice EunKyeong,Keum, Gyochang
supporting information
p. 237 - 241
(2016/12/27)

Highly efficient aqueous phase chemoselective hydrogenation of α,β-unsaturated aldehydes catalysed by phosphine-decorated polymer immobilized IL-stabilized PdNPs
Phosphino-decorated polymer immobilised ionic liquid phase stabilised palladium nanoparticles (PdNP@PPh2-PIILP) and their PEGylated counterparts (PdNP@PPh2-PEGPIILP) are remarkably active and exceptionally selective catalysts for the aqueous phase hydrogenation of α,β-unsaturated aldehydes, ketones, esters and nitriles with PdNP@PPh2-PEGPIILP giving complete conversion and 100% selectivity for reduction of the CC bond, under mild conditions. This is the most selective PdNP-based system to be reported for the aqueous phase hydrogenation of this class of substrates.
Doherty,Knight,Backhouse,Abood,Alshaikh,Fairlamb,Bourne,Chamberlain,Stones
supporting information
p. 1635 - 1641
(2017/06/05)

Switchable Site-Selective Catalytic Carboxylation of Allylic Alcohols with CO2
A switchable site-selective catalytic carboxylation of allylic alcohols has been developed in which CO2 is used with dual roles, both facilitating C?OH cleavage and as a C1 source. This protocol is characterized by its mild reaction conditions, absence of stoichiometric amounts of organometallic reagents, broad scope, and exquisite regiodivergency which can be modulated by the type of ligand employed.
van Gemmeren, Manuel,B?rjesson, Marino,Tortajada, Andreu,Sun, Shang-Zheng,Okura, Keisho,Martin, Ruben
supporting information
p. 6558 - 6562
(2017/05/29)

Heck arylation of allyl alcohol catalyzed by Pd(0) nanoparticles
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.
Tarnowicz, Stanis?awa,Alsalahi, Waleed,Mieczyńska, Ewa,Trzeciak, Anna M.
p. 5605 - 5612
(2017/08/26)

Porous Rh/BINAP polymers as efficient heterogeneous catalysts for asymmetric hydroformylation of styrene: Enhanced enantioselectivity realized by flexible chiral nanopockets
A new chiral monomer, (S)-5,5′-divinyl-BINAP, was successfully synthesized and embedded into two different porous organic polymers (Poly-1 and Poly-2). After loading a Rh species, the catalysts were applied for the heterogeneous asymmetric hydroformylation of styrene. Compared with the homogeneous BINAP analogue, the enantioselectivity of Rh/Poly-1 catalyst was drastically increased by approximately 70%. The improved enantioselectivity of the porous Rh/BINAP polymers was attributed to the presence of flexible chiral nanopockets resulting from the increased bulk of the R groups near the catalytic center.
Wang, Tao,Wang, Wenlong,Lyu, Yuan,Xiong, Kai,Li, Cunyao,Zhang, Hao,Zhan, Zhuangping,Jiang, Zheng,Ding, Yunjie
p. 691 - 698
(2017/04/24)

A PI3K/Akt Raf/MEK/ERK and as the target of the double-channel inhibitors
The invention discloses a dual-channel inhibitor using Raf/MEK/ERK and PI3K/Akt as targets. The chemical name of the composition is 1-(2-amido) ethyl-3-(3-(4-methoxyl) phenyl) allyl indole-2-ketone hydrochloride, and the structural formula (I) of the composition is as shown in the specification. The invention also discloses a preparation method of the composition and an application of the composition for preparing an anti-tumor drug. The dual-channel inhibitor disclosed by the invention has the advantages of improving titer and reducing the occurrence probability of drug resistance as well as reducing toxicity and improving the compliance of patients. Thus, the design and development of the dual-channel inhibitor provide a new chemical tool for cancer research groups, and the dual-channel inhibitor is possible to be developed as a new anti-cancer agent.
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Paragraph 0031; 0048

(2016/11/09)

Novel pyrrolo pyrimidine derivatives and composition for preventing or treating cancer comprising the same
The present invention relates to a novel pyrrolo pyrimidine compound represented by chemical formula 1, pharmaceutically acceptable salt or hydrate thereof, a manufacturing method thereof, and a pharmaceutical composition comprising the compound for preventing or treating cancer. In chemical formula 1, R^1, R^2, R^3, R^4, R^5, and X are the same as defined in the specification.COPYRIGHT KIPO 2016
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Paragraph 0166; 0167; 0168; 0169

(2016/11/24)

Synthesis and bioactivities of novel piperazine-containing 1,5-Diphenyl-2-penten-1-one analogues from natural product lead
A series of novel 1,5-Diphenyl-2-penten-1-one analogues (7a–h, 8a–h) with piperazine moiety have been designed and synthesized on the basis of natural product 1,5-Diphenyl-2-penten-1-one (I). All the synthesized compounds were evaluated in vitro for anti-plant pathogenic fungi activities and insecticidal activities. The results indicated that most of these analogues exhibited moderate antifungal activities and moderate to good insecticidal activities. Amongst them, the most potent 7c, 7e and 7h keep a mortality of 100% against larva of mosquito at the concentration of 1?mg/L. Initial structure–activity relationship (SAR) analysis showed that, a methyl group can influence the biological activities of these compounds significantly, the compounds with N′-unsubstituted piperazine showed much better antifungal activities and larvicidal activity against mosquito than the compounds with N′-methylated piperazine. In addition, the larvicidal activity against mosquito had sharply decline when the substituent on benzene ring was changed from 4-position to 2 or 3-position.
Xu, Gaofei,Yang, Xinling,Jiang, Biaobiao,Lei, Peng,Liu, Xili,Wang, Qingmin,Zhang, Xuebo,Ling, Yun
p. 1849 - 1853
(2016/07/27)

H-type zeolite-catalyzed 1,4-addition of benzene derivatives to labile acrolein
The 1,4-addition of benzene derivatives to acrolein is a straightforward way to synthesize 3-arylpropanals. A survey of acid catalysts for the 1,4-addition of methoxy-substituted benzenes to acrolein revealed that H-Beta and H-Y were the most suitable catalysts. We hypothesized three side-reactions: (1) the double 1,4-addition of acrolein to the starting benzene derivatives, (2) the Friedel-Crafts-type alkylation to the desired product, and (3) the self-polymerization of acrolein. The type (3) side-reaction was inhibited by two different methods which kept the concentration of acrolein low in the reaction mixture or in the zeolite pores. First, acrolein monomers were in situ generated through the gradual monomerization of an acrolein cyclic trimer. Second, using a reaction solvent lowered the acrolein concentration in the zeolite pores due to the competitive adsorption. We discovered that the content of monomeric acrolein in a solvent was closely related to the polarity of the solvent. Actually, both methods improved the yields for the 1,4-additions of 1,3-dimethoxybenzene to acrolein. Other electron-rich benzene derivatives, such as phenol and N, N-dimethylaniline, were also applicable to the 1,4-addition reactions.
Hayashi, Daijiro,Narisawa, Tomoyuki,Masui, Yoichi,Onaka, Makoto
supporting information
p. 460 - 471
(2016/04/26)

A Two-Component Alkyne Metathesis Catalyst System with an Improved Substrate Scope and Functional Group Tolerance: Development and Applications to Natural Product Synthesis
Although molybdenum alkylidyne complexes such as 1 endowed with triarylsilanolate ligands are excellent catalysts for alkyne metathesis, they can encounter limitations when (multiple) protic sites are present in a given substrate and/or when forcing conditions are necessary. In such cases, a catalyst formed in situ upon mixing of the trisamidomolybenum alkylidyne complex 3 and the readily available trisilanol derivatives 8 or 11 shows significantly better performance. This two-component system worked well for a series of model compounds comprising primary, secondary or phenolic -OH groups, as well as for a set of challenging (bis)propargylic substrates. Its remarkable efficiency is also evident from applications to the total syntheses of manshurolide, a highly strained sesquiterpene lactone with kinase inhibitory activity, and the structurally demanding immunosuppressive cyclodiyne ivorenolide A; in either case, the standard catalyst 1 largely failed to effect the critical macrocyclization, whereas the two-component system was fully operative. A study directed toward the quinolizidine alkaloid lythrancepine I features yet another instructive example, in that a triyne substrate was metathesized with the help of 3/11 such that two of the triple bonds participated in ring closure, while the third one passed uncompromised. As a spin-off of this project, a much improved ruthenium catalyst for the redox isomerization of propargyl alcohols to the corresponding enones was developed.
Schaubach, Sebastian,Gebauer, Konrad,Ungeheuer, Felix,Hoffmeister, Laura,Ilg, Marina K.,Wirtz, Conny,Fürstner, Alois
supporting information
p. 8494 - 8507
(2016/07/11)

Rhodium-complexed hyperbranched poly(ethyleneimine) and polyamidoamine and their non-covalent immobilization on magnetic nanoparticles
We describe a synthetic strategy for the synthesis and functionalization of hyperbranched poly(ethyleneimine) (H-PEI) and polyamidoamine (H-PAMAM) with phosphine ligands and their non-covalent immobilization on magnetic nanosupports. Treatment of these functionalized hyperbranched polymers with Rh(COD)2BF4 affords polymer-bound Rh(I) complexes that can be utilized in the hydroformylation of alkenes and in one pot hydroformylation-Knoevenagel-hydrogenation reactions. These functionalized hyperbranched polymers are linked to magnetic nanoparticles that are modified with carboxylic acid groups via ionic interactions resulting from the acid-base reactions, and are responsible for facilitating the separation of the polymeric catalysts. These magnetically retrievable polymeric catalysts can be reused for up to four cycles.
Omar, Suheir,Dutta, Bishnu,Natour, Suzana,Abu-Reziq, Raed
p. 48 - 57
(2016/06/09)

Surface bonded Rh-bis(diarylphosphine) on magnetic nanoparticles as a recyclable catalyst for hydroformylation of olefins
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.
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Page/Page column 23-24

(2016/11/21)

Organocatalytic, Enantioselective Synthesis of Cyclohexadienone Containing Hindered Spirocyclic Ethers through an Oxidative Dearomatization/Oxa-Michael Addition Sequence
An unprecedented enantioselective oxa-Michael reaction of α-tertiary alcohols using cinchona-alkaloid-based chiral bifunctional squaramide catalysts is reported. An oxidative dearomatization of phenol followed by an enantioselective oxa-Michael addition s
Reddy, Reddy Rajasekhar,Gudup, Satish Sonbarao,Ghorai, Prasanta
supporting information
p. 15115 - 15119
(2016/11/25)

Enantioselective hydroformylation of 2- and 4-substituted styrenes with PtCl2[(R)-BINAP] + SnCl2‘in situ’ catalyst
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.
Pongrácz, Péter,Kollár, László
p. 118 - 123
(2016/10/25)

An Effective Pd-Catalyzed Regioselective Hydroformylation of Olefins with Formic Acid
An effective palladium-catalyzed regioselective hydroformylation of olefins with formic acid is described. The ligand plays a crucial role in directing the reaction pathway. Linear aldehydes can be obtained in up to 93% yield with >20:1 regioselectivity using 1,3-bis(diphenylphosphino)propane (dppp) as the ligand. The reaction process is operationally simple and requires no syngas.
Ren, Wenlong,Chang, Wenju,Dai, Jie,Shi, Yuan,Li, Jingfu,Shi, Yian
supporting information
p. 14864 - 14867
(2016/11/29)

General and Mild Cobalt-Catalyzed C-Alkylation of Unactivated Amides and Esters with Alcohols
The borrowing hydrogen or hydrogen autotransfer methodology is an elegant and sustainable or green concept to construct carbon-carbon bonds. In this concept, alcohols, which can be obtained from barely used and indigestible biomass, such as lignocellulose, are employed as alkylating reagents. An especially challenging alkylation is that of unactivated esters and amides. Only noble metal catalysts based on iridium and ruthenium have been used to accomplish these reactions. Herein, we report on the first base metal-catalyzed α-alkylation of unactivated amides and esters by alcohols. Cobalt complexes stabilized with pincer ligands, recently developed in our laboratory, catalyze these reactions very efficiently. The precatalysts can be synthesized easily from commercially available starting materials on a multigram scale and are self-activating under the basic reaction conditions. This Co catalyst class is also able to mediate alkylation reactions of both esters and amides. In addition, we apply the methodology to synthesize ketones and to convert alcohols into aldehydes elongated by two carbon atoms.
Deibl, Nicklas,Kempe, Rhett
supporting information
p. 10786 - 10789
(2016/09/09)

General, Simple, and Chemoselective Catalysts for the Isomerization of Allylic Alcohols: The Importance of the Halide Ligand
Remarkably simple IrIIIcatalysts enable the isomerization of primary and sec-allylic alcohols under very mild reaction conditions. X-ray absorption spectroscopy (XAS) and mass spectrometry (MS) studies indicate that the catalysts, with the general formula [Cp*IrIII], require a halide ligand for catalytic activity, but no additives or additional ligands are needed.
Erbing, Elis,Vázquez-Romero, Ana,Bermejo Gómez, Antonio,Platero-Prats, Ana E.,Carson, Fabian,Zou, Xiaodong,Tolstoy, P?ivi,Martín-Matute, Belén
supporting information
p. 15659 - 15663
(2016/10/25)

Synthesis of 2-tetralone derivatives by Bi(OTf)3-catalyzed intramolecular hydroarylation/isomerization of propargyl alcohols
Compared to 1-tetralones, 2-tetralones are expensive, less stable, and difficult to synthesize. A concise Bi-catalyzed method was developed for the synthesis of 2-tetralones from 5-phenylpent-1-yn-3-ol derivatives. Diverse 2-tetralones were obtained in moderate to good yields under mild conditions.
Yun, Jihee,Park, Jungmin,Kim, Jaehyun,Lee, Kooyeon
p. 1045 - 1048
(2015/02/19)

Hydroformylation of olefins and reductive carbonylation of aryl halides with syngas formed ex situ from dehydrogenative decarbonylation of hexane-1,6-diol
A variety of primary alcohols have been investigated as convenient substrates for the ex situ delivery of carbon monoxide and molecular hydrogen in a two-chamber reactor. The gaseous mixture is liberated in one chamber by an iridium-catalysed dehydrogenative decarbonylation of the alcohol and then consumed in the other chamber in either a rhodium-catalysed hydroformylation of olefins or a palladium-catalysed reductive carbonylation of aryl halides. Hexane-1,6-diol was found to be the optimum alcohol for both reactions where moderate to excellent yields were obtained of the product aldehydes. A relatively low pressure of 1.5-2.4 bar was measured in the closed system during the two transformations.
Christensen, Stig Holden,Olsen, Esben P. K.,Rosenbaum, Jascha,Madsen, Robert
p. 938 - 945
(2015/02/19)

Promotion effect of water on hydroformylation of styrene and its derivatives with presence of amphiphilic zwitterionic phosphines
Two kinds of novel zwitterionic phosphines of L1 and L2 have been synthesized in which the sulfonate groups (-SO3-) are incorporated to render them amphiphilic. Both of them are strong π-acceptor ligands in which the positive-charged imidazoliums with intensive electron-withdrawing effect are vicinal to the coordinating phosphorous atoms. The amino-group of piperidyl is additionally incorporated in L2 to make it behave as a hybrid ligand with potential hemilability. The comparison of the ligands of L1 and L2 in Rh-catalyzed hydroformylation of styrene (and its derivatives) and the effect of water on their behaviors were discussed. Without the involvement of water, the catalytic system of Rh(acac)(CO)2-L2 exhibited lower activity than that of Rh(acac)(CO)2-L1 under the same conditions. However, the dramatic promotion effect of water as a suspension was observed especially for Rh(acac)(CO)2-L2 system with TOF spurred up from 195 to 470 h-1. The corresponding in situ high pressure FT-IR spectral information showed that the presence of water in Rh(acac)(CO)2-L2 system greatly facilitated the formation and stability of the active Rh-H species (νRh-H, 2047 cm-1), which was in charge of the efficient hydroformylation of styrene and its derivatives.
Chen, Sheng-Jie,Li, Yong-Qi,Wang, Peng,Lu, Yong,Zhao, Xiao-Li,Liu, Ye
p. 212 - 220
(2015/07/28)