cas 5349-60-0, 1-(4-METHYOXYPHENYL)-1-PROPANOL 97

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2,2′-Bipyridine-α,α′-trifluoromethyl-diol ligand: Synthesis and application in the asymmetric Et2Zn alkylation of aldehydes
A chiral 2,2′-bipyridine ligand (1) bearing α,α′-trifluoromethyl-alcohols at 6,6′-positions was designed in five steps affording either the R,R or S,S enantiomer with excellent stereoselectivities, i.e. 97% de, >99% ee and >99.5% de, >99.5% ee, respectively. The key step for reaching high levels of stereoselectivity was demonstrated to be the resolution of the α-CF3-alcohol using (S)-ibuprofen as the resolving agent. An initial application for the 2,2′-bipyridine-α,α′-CF3-diol ligand was highlighted in the ZnII-catalyzed asymmetric ethylation reaction of aromatic, heteroaromatic, and aliphatic aldehydes. Synergistic electron deficiency and steric hindrance properties of the newly developed ligand afforded the corresponding alcohols in good to excellent yields (up to 99%) and enantioselectivities (up to 95% ee). As observed from single crystal diffraction analysis, the complexation of the 2,2′-bipyridine-α,α′-CF3-diol ligand generates an unusual hexacoordinated ZnII.
Lauzon, Samuel,Ollevier, Thierry
supporting information
p. 11025 - 11028
(2021/11/03)

Rhodium-Catalyzed Regiodivergent Synthesis of Alkylboronates via Deoxygenative Hydroboration of Aryl Ketones: Mechanism and Origin of Selectivities
Here, we report an efficient rhodium-catalyzed deoxygenative borylation of ketones to synthesize alkylboronates, in which the regioselectivity can be switched by the choice of the ligand. The linear alkylboronates were obtained exclusively in the presence of P(nBu)3, and PPh2Me favored the formation of branched alkylboronates. The protocol also allows access to 1,1,2-triboronates from the readily available ketones. Mechanistic studies suggest that this Rh-catalyzed deoxygenative borylation of ketones goes through an alkene intermediate, which undergoes regiodivergent hydroboration to afford linear and branched alkylboronates. The different steric effects of PPh2Me and P(nBu)3 were found to be responsible for product selectivity by density functional theory calculations. The alkene intermediate can alternatively undergo sequential dehydrogenative borylation and hydroboration to deliver the triboronates.
Zhang, Bing,Xu, Xin,Tao, Lei,Lin, Zhenyang,Zhao, Wanxiang
p. 9495 - 9505
(2021/08/04)

Production of enantiopure chiral aryl heteroaryl carbinols using whole‐cell Lactobacillus paracasei biotransformation
Aryl and heteroaryl chiral carbinols are useful precursors in the synthesis of drugs. Lactobacillus paracasei BD87E6, which is obtained from a cereal based fermented beverage, was investigated as whole cell biocatalyst for the bioreduction of different ketones (including aromatic, hetero-aromatic and fused bicyclic ketone) into chiral carbinols, which can be used as a pharmaceutical intermediate. The study shows that bioreduction of aryl, heteroaryl and fused bicyclic ketone (1–5) to their corresponding chiral carbinols (1a–5a) in excellent enantioselectivity (>99%) with high yields. This study gave the first example for an enantiopure production of (S)-6-chlorochroman-4-ol (3a), which has many antioxidant activity, by a biological method. For asymmetric bioreduction of other prochiral ketones, these results open way to use of L. paracasei BD87E6 as biocatalysts. Also, the present process shows a hopeful and alternative green synthesis for the production of enantiopure carbinols in a mild, inexpensive and environmentally friendly process.
?ahin, Engin
p. 549 - 557
(2020/01/08)

Oxygenation of styrenes catalyzed by N-doped carbon incarcerated cobalt nanoparticles
NCI-Co catalyzed olefin oxygenation reactions were investigated. Among the metals examined, including noble metals, the reaction proceeded specifically on Co catalysts, and nitrogen dopant was crucial for the catalytic activity. The presence of NaBH4 as a hydride source, the corresponding alcohols were obtained in high yields. The substrates bearing a reductant-sensitive functional group were made tolerant by changing the reductant and using an additive, and furthermore, the corresponding ketones were accessed by changing reaction conditions. A preliminary examination of other SOMOphiles suggested that the heterogeneous catalyst systems have the potential to be applied to more general hydrofunctionalization of olefins to form various kinds of bonds. Several mechanistic studies suggested that the reaction proceeded in a heterogeneous manner and formed a radical intermediate on cobalt nanoparticle species.
Yasukawa, Tomohiro,Kobayashi, Shū
supporting information
p. 1980 - 1985
(2019/12/24)

Production of enantiomerically enriched chiral carbinols using Weissella paramesenteroides as a novel whole cell biocatalyst
In this study, four bacterial strains were tested for their ability to reduce acetophenones to its corresponding alcohol. Among these strains Weissella paramesenteroides N7 was found to be the most successful biocatalyst to reduce the ketones to the corresponding alcohols. The reaction conditions were systematically optimized for W. paramesenteroides N7 that resulted in high enantioselectivity and conversion rates for the bioreduction. The scale-up asymmetric reduction of 1-(4-methoxyphenyl) propan-1-one (1r) by W. paramesenteroides N7 gave (R)-1-(4-methoxyphenyl) propan-1-ol (2r) with 94% yield and >99% enantiomeric excess. This is the first report showing the synthesis of (R)-1-(4-methoxyphenyl) propan-1-ol (2r) in enantiopure form using a biocatalyst on a gram scale. The whole cell catalyzed the reductions of ketone substrates on the preparative scale, demonstrating that W. paramesenteroides N7 would be a valuable biocatalyst for the preparation of chiral aromatic alcohols of pharmaceutical interest as a promising and alternative green approach.
Tozlu, Caner,?ahin, Engin,Serencam, Hüseyin,Dertli, Enes
p. 388 - 398
(2019/02/14)

Compound, resin, and a method for manufacturing a resist pattern a resist composition (by machine translation)
[A] producing a resist pattern having a good CD uniformity compound, resin and resist composition. (I) a compound represented by the formula [a], and a resin composition. [In the formula (I), R1 Is, a hydrogen atom or a methyl group. R2 The, 1 - 6 carbon atoms in the alkyl group. R3 Is, a hydrogen atom or an alkyl group of 1 - 6 represent. The Ar, substituted divalent aromatic hydrocarbon group having a carbon number of 6 - 36 may represent 2. R4 The, 1 - 12 carbon atoms have a substituent which may be fluorinated alkyl groups. ][Drawing] no (by machine translation)
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Paragraph 0209

(2020/01/28)

Chiral zinc amidate catalyzed additions of diethylzinc to aldehydes
A series of bifunctional spiro ligands bearing “carboxamide–phosphine oxide” groups and ethylzinc carboxamidates from these ligands as catalysts for Et2Zn additions to aldehydes were reported. Excellent yields were obtained with moderate ee′s in Et2Zn additions to benzaldehyde derivatives, implying effectiveness of our newly designed catalytic structures as well as mediocre stereocontrol by these chiral ligands. Possible transition states were suggested based on the crystal structures of two ligands.
Zhang, Jinxia,Li, Shasha,Zheng, Xinxin,Li, Hongjie,Jiao, Peng
supporting information
p. 1913 - 1917
(2019/06/24)

Ni-Catalyzed β-Alkylation of Cyclopropanol-Derived Homoenolates
Metal homoenolates are valuable synthetic intermediates which provide access to β-functionalized ketones. In this report, we disclose a Ni-catalyzed β-alkylation reaction of cyclopropanol-derived homoenolates using redox-active N-hydroxyphthalimide (NHPI) esters as the alkylating reagents. The reaction is compatible with 1°, 2°, and 3° NHPI esters. Mechanistic studies imply radical activation of the NHPI ester and 2e β-carbon elimination occurring on the cyclopropanol.
Mills, L. Reginald,Zhou, Cuihan,Fung, Emily,Rousseaux, Sophie A. L.
supporting information
p. 8805 - 8809
(2019/11/03)

CuH-Catalyzed Enantioselective Ketone Allylation with 1,3-Dienes: Scope, Mechanism, and Applications
Chiral tertiary alcohols are important building blocks for the synthesis of pharmaceutical agents and biologically active natural products. The addition of carbon nucleophiles to ketones is the most common approach to tertiary alcohol synthesis but traditionally relies on stoichiometric organometallic reagents that are difficult to prepare, sensitive, and uneconomical. We describe a mild and efficient method for the copper-catalyzed allylation of ketones using widely available 1,3-dienes as allylmetal surrogates. Homoallylic alcohols bearing a wide range of functional groups are obtained in high yield and with good regio-, diastereo-, and enantioselectivity. Mechanistic investigations using density functional theory (DFT) implicate the in situ formation of a rapidly equilibrating mixture of isomeric copper(I) allyl complexes, from which Curtin-Hammett kinetics determine the major isomer of the product. A stereochemical model is provided to explain the high diastereo- and enantioselectivity of this process. Finally, this method was applied to the preparation of an important drug, (R)-procyclidine, and a key intermediate in the synthesis of several pharmaceuticals.
Li, Chengxi,Liu, Richard Y.,Jesikiewicz, Luke T.,Yang, Yang,Liu, Peng,Buchwald, Stephen L.
supporting information
p. 5062 - 5070
(2019/03/26)

A Dual-Functional Catalyst for Cascade Meerwein–Pondorf–Verley Reduction and Dehydration of 4″-Methoxypropiophenone to Anethole
Anethole is an ingredient in many flavours, fragrances and pharmaceutical formulations. To reduce the dependence of its supply on natural oils, a green route for anethole synthesis was designed on the basis of Meerwein–Pondorf–Verley (MPV) reduction and dehydration of 4′-methoxypropiophenone. The one-pot cascade reactions were heterogeneously catalysed by dual-functional Zr-MSU-3, a predominantly Lewis-acidic catalyst with a Si/Zr ratio of 10 and pores with sizes in the range of 3.2–4.2 nm. The use of 2-pentanol as solvent and hydrogen donor for the MPV reduction was advantageous, as its high boiling point enhances the rate of the reactions, especially the dehydration of the MPV product, 1-(4-methoxyphenyl)-propan-1-ol. This dispenses with the need for a strong acid catalyst that could result in by-products of acid-catalysed reactions. Anethole yields of 91 % with a trans/cis isomer ratio of about 92:8, similar to that of natural anethole, were obtained. In comparison, microporous Zr-beta (Si/Zr 12.5) gave lower activity owing to pore-size constraints. Hence, through design of the reactions and catalyst, 4′-methoxypropiophenone can be efficiently converted to anethole in a sustainable and green manner.
Zhang, Hongwei,Lim, Candy Li-Fen,Zaki, Muhammad,Jaenicke, Stephan,Chuah, Gaik Khuan
p. 3007 - 3017
(2018/08/03)

Chiral 2-(2-hydroxyaryl)alcohols (HAROLs) with a 1,4-diol scaffold as a new family of ligands and organocatalysts
Efficient and modular syntheses of chiral 2-(2-hydroxyaryl)alcohols (HAROLs), novel 1,4-diols carrying one phenolic and one alcohol hydroxyl group, have been developed which led to generation of a small library of structurally diverse HAROLs in enantiomerically pure form. Of the different HAROLs examined, a HAROL based on the indan backbone exhibited the highest activity and enantioselectivity in the 1,2-addition of certain organometallic compounds to aldehydes in the presence of Ti(OiPr)4 (up to 97% y, 88% ee) and performed as a hydrogen-bond donor organocatalyst in the Morita-Baylis-Hillman reaction, promoted by trialkylphosphines.
Dilek, ?mer,Tezeren, Mustafa A.,Tilki, Tahir,Ertürk, Erkan
supporting information
p. 268 - 286
(2017/12/06)

Central-to-Helical-to-Axial-to-Central Transfer of Chirality with a Photoresponsive Catalyst
Recent advances in molecular design have displayed striking examples of dynamic chirality transfer between various elements of chirality, e.g., from central to either helical or axial chirality and vice versa. While considerable progress in atroposelective synthesis has been made, it is intriguing to design chiral molecular switches able to provide selective and dynamic control of axial chirality with an external stimulus to modulate stereochemical functions. Here, we report the synthesis and characterization of a photoresponsive bis(2-phenol)-substituted molecular switch 1. The unique design exhibits a dynamic hybrid central-helical-axial transfer of chirality. The change of preferential axial chirality in the biaryl motif is coupled to the reversible switching of helicity of the overcrowded alkene core, dictated by the fixed stereogenic center. The potential for dynamic control of axial chirality was demonstrated by using (R)-1 as switchable catalyst to direct the stereochemical outcome of the catalytic enantioselective addition of diethylzinc to aromatic aldehydes, with successful reversal of enantioselectivity for several substrates.
Pizzolato, Stefano F.,?tacko, Peter,Kistemaker, Jos C. M.,Van Leeuwen, Thomas,Otten, Edwin,Feringa, Ben L.
supporting information
p. 17278 - 17289
(2019/01/04)

MeZnOMe-mediated reaction of aldehydes with Grignard reagents: A glance into nucleophilic addition/Oppenauer oxidation pathway
A novel organozincate of RMgX ?MeZnOMe ?LiCl type, formed in situ via transmetalation of Grignard reagent RMgBr ?LiCl with MeZnOMe, is shown to be an excellent organometallic species in the nucleophilic addition/Oppenauer oxidation of aldehydes to generate aromatic ketones in high yield. This transformation allows quick access to structurally diverse aryl, heteroaryl, benzyl and alkyl ketones with broad substrate scope and excellent functional group tolerance.
Fu, Ying,Ma, Xian-Zhen,Shi, Chun-Zhao,Shen, Tong,Du, Zhengyin
(2018/07/31)

Pure phosphotriesters as versatile ligands in transition metal catalysis: efficient hydrosilylation of ketones and diethylzinc addition to aldehydes
This work aims to highlight the underrated role played by pure phosphotriester (or phosphate) ligands in catalysis, when compared to other phosphorus-containing donors such as phosphane oxides or phosphites. To probe this and to enlarge the very narrow catalytic scope of these Lewis bases, easily accessible mono- and bidentate phosphotriesters were tested as donors in two important transition metal-based catalytic transformations: the zinc-catalyzed hydrosilylation of ketones and the titanium-promoted diethylzinc addition to aldehydes. In both cases, the reactions were successful and the corresponding alcohols were obtained in high yields.
Bouhachicha,Ngo Ndimba,Roisnel,Lalli,Argouarch
p. 4767 - 4770
(2017/07/11)

Mechanistic implications of the enantioselective addition of alkylzinc reagents to aldehydes catalyzed by nickel complexes with α-amino amide ligands
The enantioselective alkylation of aldehydes catalysed by nickel(ii)-complexes derived from α-amino amides was studied by means of density functional theory (DFT) and ONIOM (B3LYP:UFF) calculations. A mechanism was proposed in order to investigate the origin of enantioselectivity. The chirality-determining step for the alkylation was the formation of the intermediate complexes with the involvement of a 5/4/4-fused tricyclic transition state. The predominant products predicted theoretically were of (S)-configuration, in good agreement with experimental observations. The scope of the reaction was examined and high yields and enantioselectivities were observed for the enantioselective addition of Et2Zn and Me2Zn to aromatic and aliphatic aldehydes.
Escorihuela, Jorge,Burguete, M. Isabel,Ujaque, Gregori,Lledós, Agustí,Luis, Santiago V.
supporting information
p. 11125 - 11136
(2016/12/07)

Aluminum Monohydride Catalyzed Selective Hydroboration of Carbonyl Compounds
The well-defined aluminum monohydride compound [{(2,4,6-Me3-C6H2)NC(Me)}2(Me)(H)]AlH·(NMe2Et) (1) catalyzes hydroboration of a wide range of aldehydes and ketones under mild reaction conditions. Moreover, compound 1 displayed chemoselective hydroboration of aldehydes over ketones at rt.
Jakhar, Vineet Kumar,Barman, Milan Kr.,Nembenna, Sharanappa
p. 4710 - 4713
(2016/09/28)

Novel CRAC channel conditioning agent, and preparation method and applications thereof
The invention provides a novel CRAC (calcium release-activated calcium) channel conditioning agent, and a preparation method and applications thereof, and more specifically, the invention provides a compound represented by formula I, and the groups are defined in the patent specification. The invention also provides the preparation method of the compound represented by formula I, and applications of the compound as a CRAC channel conditioning agent.
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Paragraph 0354; 0355; 0356; 0357; 0358

(2016/10/08)

Bu4NI-Catalyzed α-Oxyacylation of Carbonyl Compounds with Toluene Derivatives
A TBAI (tetrabutylammonium iodide)-catalyzed direct α-oxyacylation of carbonyl compounds from readily available toluene derivatives has been developed. The distinguished features of this metal-free protocol include the employment of simple starting material, a wide carbonyl compound scope, and mild reaction conditions.
Li, Chengliang,Jin, Tao,Zhang, Xinglu,Li, Chunju,Jia, Xueshun,Li, Jian
supporting information
p. 1916 - 1919
(2016/05/19)

Magnesium salt promoted tandem nucleophilic addition-Oppenauer oxidation of aldehydes with organozinc reagents
A magnesium salt promoted synthesis of ketones via tandem nucleophilic addition-Oppenauer oxidation of aldehydes using organozinc chemistry was demonstrated. Magnesium salts concomitantly generated via magnesium metal mediated organohalide zincation exhibit high efficacy for nucleophilic addition of organozinc reagents to aromatic aldehydes and thereafter Oppenauer oxidation whereby ketones are formed in high to excellent yields.
Fu, Ying,Zhao, Xing Ling,Hügel, Hulmet,Huang, Danfeng,Du, Zhengyin,Wang, Kehu,Hu, Yulai
p. 9720 - 9724
(2016/10/31)

A versatile and one-pot strategy to synthesize ?±-amino ketones from benzylic secondary alcohols using N -bromosuccinimide
A metal-free one-pot strategy has been developed for the first time to synthesize pharmaceutically important ?±-amino ketones from readily available benzylic secondary alcohols and amines using N-bromosuccinimide. This new reaction proceeds via three consecutive steps involving oxidation of alcohols, ?±-bromination of ketones, and nucleophilic substitution of ?±-bromo ketones to give ?±-amino ketones. Importantly, this novel one-pot greener reaction avoids direct usage of toxic and corrosive bromine. This methodology has been employed efficiently to synthesize pharmaceutically important amfepramone and pyrovalerone in a single step.
Guha, Somraj,Rajeshkumar, Venkatachalam,Kotha, Surya Srinivas,Sekar, Govindasamy
supporting information
p. 406 - 409
(2015/03/04)

Novel chiral N,N′-dimethyl-1,4-piperazines with metal binding abilities
With the objective of developing novel chiral ligands, we report an efficient strategy to prepare chiral N,N-dimethyl-1,4-piperazines, six-member heterocyclic molecules that possess metal binding features. We prepared and characterized 18 piperazines, and evaluated their ability to complex different mono- and divalent metals, using a rapid picrate extraction technique. Some newly prepared diamine ligands were used in diethylzinc alkylation of aryl aldehydes. Yields increased significantly in the presence of the diamine ligands, though enantioselectivity was low. The results demonstrate the validity of the approach for preparing and identifying useful chiral diamine ligands.
Bérubé, Christopher,Cardinal, Sébastien,Boudreault, Pierre-Luc,Barbeau, Xavier,Delcey, Nicolas,Giguère, Martin,Gleeton, Dave,Voyer, Normand
p. 8077 - 8084
(2015/12/30)

A novel synthesis of isoeugenol, [ring-(U)-14C]
A novel method for the preparation of isoeugenol, [ring-(U)-14C] is presented. Phenols and phenyl esters substituted in the para position with 1-hydroxyethyl or 1-hydroxypropyl acetate esters when treated with 1,8-diazabicyclo[5.4.0]undec-7-ene in dimethylformamide (DMF) eliminate the alkyl carboxylate function to give the unsaturated compound. The reaction fails with unsubstituted or ether substituted phenyl 1-hydroxyacetate esters.
Immoos, John E.
p. 419 - 424
(2015/11/18)

Synthesis of highly substituted γ-butyrolactones by a gold-catalyzed cascade reaction of benzyl esters
Easily accessible benzylic esters of 3-butynoic acids in a gold-catalyzed cyclization/rearrangement cascade reaction provided 3-propargyl γ-butyrolactones with the alkene and the carbonyl group not being conjugated. Crossover experiments showed that the formation of the new C-C bond is an intermolecular process. Initially propargylic-benzylic esters were used, but alkyl-substituted benzylic esters worked equally well. In the case of the propargylic- benzylic products, a simple treatment of the products with aluminum oxide initiated a twofold tautomerization to the allenyl-substituted g-butyrolactones with conjugation of the carbonyl group, the olefin, and the allene. The synthetic sequence can be conducted stepwise or as a one-pot cascade reaction with similar yields. Even in the presence of the gold catalyst the new allene remains intact.
Jaimes, Maria Camila Blanco,Ahrens, Alexander,Pfl?sterer, Daniel,Rudolph, Matthias,Hashmi, A. Stephen K.
supporting information
p. 427 - 433
(2015/02/18)

Asymmetric transfer hydrogenation of secondary allylic alcohols
Racemic secondary allylic alcohols were transformed into optically active secondary alcohols by a combined Rucatalyzed isomerization/asymmetric transfer-hydrogenation reaction. The catalyst was generated in situ in isopropyl alcohol from di-μ-chlorobis[(p-cymene)chlororuthenium(II)], the chiral ligand (1S,2S)-N-(p-tolylsulfonyl)-1,2-diphenylethylenediamine, and K2CO3, and the products were afforded in yields up to 97% with up to 93% enantiomeric excess without the use of hydrogen gas. A Hammett study revealed that the reaction rate was enhanced with electronwithdrawing aryl substituents. The reaction supports the recent work published by Adolfsson et al. as new methodology for the synthesis of chiral compounds from allylic alcohols.
Shoola, Christopher O.,DelMastro, Thomas,Wu, Ruoqiu,Sowa, John R.
p. 1670 - 1673
(2015/05/27)

DMF Dimethyl Acetal as Carbon Source for α-Methylation of Ketones: A Hydrogenation-Hydrogenolysis Strategy of Enaminones
A novel heterogeneous catalytic hydrogenation-hydrogenolysis strategy has been developed for the α-methylation of ketones via enaminones using DMF dimethyl acetal as carbon source. This strategy provides a very convenient route to α-methylated ketones using a variety of ketones without any base or oxidant. (Chemical Equation Presented).
Borah, Ashwini,Goswami, Limi,Neog, Kashmiri,Gogoi, Pranjal
p. 4722 - 4728
(2015/05/13)

The cooperative effect of Lewis pairs in the Friedel-Crafts hydroxyalkylation reaction: A simple and effective route for the synthesis of (±)-carbinoxamine
An efficient C-C bond formation strategy between aromatic/heteroaromatic π-nucleophiles and Lewis acid activated aldehydes is described. This aromatic electrophilic substitution reaction of arenes or heteroarenes is facilitated by Lewis acid AlBr3. Aromatic rings with electron donating substituents are excellent nucleophilic counterparts in this reaction, generating carbinols in excellent yields (61-94%). The formation of triarylmethanes is also witnessed in the case of certain reactive aldehydes and aromatic π-nucleophiles through reactive carbocation formation. The formation of triarylmethane is reduced to a greater extent via retardation of the second π-nucleophile addition through a Lewis base, for example, pyridine, coordination with an aluminium alkoxide intermediate. Various aliphatic aldehydes also underwent Friedel-Crafts type hydroxyalkylation and generated the expected carbinols in moderate yields (41-53%) in the presence of AlBr3. This protocol has been successfully applied to the synthesize of the (±)-carbinoxamine, a therapeutically important histamine H1 antagonist, in a one-pot manner.
Harikrishnan, Adhikesavan,Sanjeevi, Jayakumar,Ramanathan, Chinnasamy Ramaraj
p. 3633 - 3647
(2015/03/30)

Efficient assembly of α-aryl and α-vinyl nitriles via iron-catalyzed ether bond activation
A novel and practical method for the synthesis of diverse α-aryl and α-vinyl nitriles was developed via an iron-catalyzed sp3 C-O ether bond cleavage with C-C bond formation in the reaction of π-activated ethers with TMSCN.
Fan, Xiaohui,Guo, Kun,Guan, Yong-Hong,Fu, Lin-An,Cui, Xiao-Meng,Lv, Hao,Zhu, Hong-Bo
supporting information
p. 1068 - 1071
(2014/02/14)

A catalytic system for the activation of diorganozinc reagents
We report a novel catalytic system for the activation of diorganozinc reagents. We assumed that the nucleophilic activation of diethylzinc should be efficiently performed by simple alkali metal salts. Indeed, the combination of sodium salts and 15-crown-5 significantly accelerates the rate of diethylzinc addition to benzaldehyde under mild conditions. The activity of the catalytic system strongly depends on the nature of the anion, decreasing in the order I->Br->Cl->F-. Under the optimized reaction conditions, various aryl, hetero aryl, and aliphatic aldehydes were converted with diethylzinc and the corresponding product was obtained in excellent yields. The first X-ray absorption spectroscopy measurements on such type of reactions provide initial insights that support the proposed catalytic cycle and suggest the formation of a zincate complex.
Werner, Thomas,Bauer, Matthias,Riahi, Abdol Majid,Schramm, Heiko
p. 4876 - 4883
(2014/08/05)

The dual role of ruthenium and alkali base catalysts in enabling a conceptually new shortcut to N-unsubstituted pyrroles through unmasked α-amino aldehydes
A virtually salt-free and straightforward bimolecular assembly giving N-unsubstituted pyrroles through fully unmasked α-amino aldehydes, which was enabled by the dual effects of a catalytic ruthenium complex and an alkali metal base, is reported. Either solvent-free or acceptorless dehydrogenation facilitates high atom, step, and pot economy, which are otherwise difficult to achieve in multistep operations involving protection/deprotection.
Iida, Kazuki,Miura, Takashi,Ando, Junki,Saito, Susumu
supporting information
p. 1436 - 1439
(2013/06/26)

Cluster-organic framework materials as heterogeneous catalysts for high efficient addition reaction of diethylzinc to aromatic aldehydes
To explore the catalytic activity of heterometallic cluster-organic frameworks, three 3d-3d heterometallic cluster-organic frameworks based on the cooperative assembly of tetrahedral Cu4I4 and metal-carboxylate clusters with potential open metal sites were synthesized and described in detail. The structure of 1 consists of tetrahedral [Cu 4I4(INA)4]4- metalloligands (INA = isonicotinate) linking unusual Zn8(μ4-O)(COO) 12(H2O)4 clusters into a (4,12)-connected network. Compound 2 features a 2-fold interpenetrating 4-connected bbf-type framework based on new [Cu4I4(INA)2(DBO) 2]2- metalloligands (DBO = 1,4-diazabicyclo[2.2.2]octane) and paddle-wheel Zn2(COO)4 units. The 2-fold interpenetrating diamond-type framework 3 is constructed from tetrahedral [Cu4I4(INA)4]4- metalloligand and Mn2(COO)4(H2O)2(DMF) unit with potential open Mn centers. All three framework materials have notable catalytic activity on the diethylzinc addition to aromatic aldehydes, and the catalytic properties of compound 1 have been studied in detail. The results reveal that the heterogeneous catalysis of the diethylzinc addition to aromatic aldehydes by using cluster-organic framework as catalyst is determined by several experimental factors, such as temperature, reaction time, and the incorporation of electron-withdrawing groups in aromatic aldehydes.
Tan, Yan-Xi,He, Yan-Ping,Zhang, Jian
p. 4711 - 4716
(2013/03/13)

NANOSTRUCTURED METALS
The invention relates to a nanoparticulate material comprising long ultrathin metal nanowires, and to processes for making it. The nanoparticulate material may be used as a catalyst and, in the presence of a chiral modifier, can catalyse enantioselective reactions.
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(2012/06/16)

Phosphonium salt catalyzed addition of diethylzinc to aldehydes
The addition of diethylzinc to aromatic, heteroaromatic, and aliphatic aldehydes at room temperature is efficiently catalyzed by 1-7 mol% tetrabutylphosphonium chloride. The corresponding addition products are obtained in good to excellent yields of up to 99%. Moreover, polymer bond phosphonium salts can be used to catalyze this reaction with excellent recovery of the polymer bond catalyst up to three cycles. The application of chiral bifunctional phosphonium salts revealed a remarkable counter anion effect. Changing the anion, the activity of the tetrabutylphosphonium salt decreased in the order Cl- > Br- > I- ≈ TsO- > BF4- ≈ PF6-. However, the nature of the cation had also significant influence. Tetraalkyl-ammonium chlorides showed similar activity compared to phosphonium chlorides, while alkaline metal chlorides proved to be considerably less active. Georg Thieme Verlag Stuttgart.
Werner, Thomas,Riahi, Abdol Majid,Schramm, Heiko
experimental part
p. 3482 - 3490
(2011/12/04)

Synthesis and characterization of ruthenium(II) complexes based on diphenyl-2-pyridylphosphine and their applications in transfer hydrogenation of ketones
Synthesis and characterization of the ruthenium complexes [RuH(CO)Cl(κ1-P-PPh2Py)2(PPh 3)] (1) and [Ru(CO)Cl2(κ1-P-PPh 2Py)(κ2-P-N-PPh2Py)] (2) containing diphenyl-2-pyridylphosphine (PPh2Py) are described. Spectral and structural data suggested linkage of the PPh2Py in κ1-P bonding mode in 1 and both the κ1-P and κ2-P-N bonding modes in 2. The complex 1 reacted with N,N-donor bases viz., ethylenediamine (en), N,N′-dimethyl-(ethylenediamine) (dimen), 1,3-diaminopropane (diap), 2,2′-bipyridine (bipy), 1,10-phenanthroline (phen) and di-2-pyridylaminomethylbenzene (dpa) to afford cationic complexes of formulation [RuH(CO)(κ1-P-PPh 2Py)2(N-N)]+ (3-8) [N-N = en, 3; dimen, 4; diap, 5; bipy, 6; phen, 7; and dpa, 8], which have been isolated as their tetrafluoroborate salts. The complexes under investigation have been characterized by elemental analyses, spectroscopic and electrochemical studies. Molecular structures of 2, 3, 6, and 8 have been determined by single crystal X-ray diffraction analyses. Further, the complexes 1-8 act as effective precursor catalyst in transfer hydrogenation of acetophenone/ketones in basic 2-propanol.
Kumar, Prashant,Singh, Ashish Kumar,Yadav, Mahendra,Li, Pei-Zhou,Singh, Sanjay Kumar,Xu, Qiang,Pandey, Daya Shankar
experimental part
p. 124 - 131
(2011/05/07)

A synergic blend of newly isolated pseudomonas mandelii KJLPB5 and [hmim]Br for chemoselective 2° aryl alcohol oxidation in H2O2: Synthesis of aryl ketone or aldehydes via sequential dehydration-oxidative C=C cleavage
Pseudomonas mandelii KJLPB5 is reported for the oxidation of aryl alcohols in ionic liquid [hmim]Br (1-hexyl-3-methyl imidazolium bromide) with H 2O2. With a slight alteration of reaction conditions, the developed protocol leads either to (i) chemoselective oxidation of 2° aryl alcohols over 1° and aliphatic counterparts or (ii) direct one pot-two step sequential conversion of 2° aryl alcohols into corresponding one or two carbons shorter aryl aldehydes through oxidative cleavage pathway, thus providing a new facet to metal-free oxidations. The key operational parameters such as substrate concentration, incubation temperature, incubation time, ionic liquid type and ionic liquid concentration are also optimized. Graphical Abstract: [Figure not available: see fulltext.]
Sharma, Nandini,Sharma, Upendra K.,Salwan, Richa,Kasana, Ramesh C.,Sinha, Arun K.
scheme or table
p. 616 - 622
(2012/01/14)

Selective palladium-loaded MIL-101 catalysts
Palladium nanoparticles (NPs) of different mean particle size have been synthesized in the host structure of the porous coordination polymer (or metal-organic framework: MOF) MIL-101. The metal-organic chemical vapor deposition method was used to load MIL-101 with the Pd precursor complex [(η5-C5H5)Pd(η3-C 3H5)]. Loadings higher than 50 wt.% could be accomplished. Reduction of the Pd precursor complex with H2 gave rise to Pd NPs inside the MIL-101 (Pd@MIL-101). The reduction conditions, especially the temperature, allows us to make size-conform (size of the Pd NPs correlates with the size of the cavities of the host structure of MIL-101) and undersized Pd NPs. The Pd@MIL-101 samples were characterized by X-ray diffraction, IR spectroscopy, Brauner-Emmett-Teller (BET) analysis, elemental analysis, and transmission electron microscopy (TEM). Catalytic studies, hydrogenation of ketones, were performed with selected Pd@MIL-101 catalysts. Activity, selectivity, and recyclability of the catalyst family are discussed.
Hermannsdoerfer, Justus,Kempe, Rhett
experimental part
p. 8071 - 8077
(2011/09/12)

Synthesis and structural features of chiral cyclic squaramides and their application in asymmetric catalytic reaction
We report the synthesis and structural elucidation of two series of chiral cyclic squaramides, i.e. six-and twelve-membered ring squaramides 4 and 6, based on the cyclobutenedione structure, containing enantiomerically pure (1R,2R)-1,2-diphenylethylenediamine as the chiral element. Compounds 4a-d obtained from alkylation of 3, crystallize in space groups of monoclinic P2 1, monoclinic P21, monoclinic chiral P212 121, and the orthorhombic C2221, respectively. For the first time the crystal structures of six-membered ring chiral cyclic squaramides are reported. These novel ligands have been tested in the enantioselective addition of diethylzinc to aryl aldehydes to give the corresponding alcohols in moderate yields, albeit with low enantioselectivity. ARKAT-USA, Inc.
Jin, Xiaoqing,Min, Qiaoqiao,Zheng, Yangfan,Wang, Pengcheng,Zhu, Jun,Zhou, Hai-Bing
experimental part
p. 322 - 335
(2011/03/17)

Chemoselective and regiospecific suzuki coupling on a multisubstituted sp3-Carbon in 1,1-diborylalkanes at room temperature
The palladium-catalyzed Suzuki-Miyaura cross-coupling on a multisubstituted sp3-carbon in 1,1-diborylalkanes was achieved at room temperature. The generation of a monoborate intermediate by virtue of the adjacent B atom could result in the chemoselective coupling reaction under ambient conditions.
Endo, Kohei,Ohkubo, Takahiro,Hirokami, Munenao,Shibata, Takanori
supporting information; experimental part
p. 11033 - 11035
(2010/09/16)

Ruthenium-catalyzed redox isomerization/transfer hydrogenation in organic and aqueous media: A one-pot tandem process for the reduction of allylic alcohols
The hexamethylbenzene-ruthenium(ii) dimer [{RuCl(μ-Cl) (η6-C6Me6)}2] 1 and the mononuclear bis(allyl)-ruthenium(iv) complex [RuCl2(η 3:η2:η3-C12H 18)]2, associated with base and a hydrogen donor, were found to be active catalysts for the selective reduction of the CC bond of allylic alcohols both in organic and aqueous media. The process, which proceeds in a one-pot manner, involves a sequence of two independent reactions: (i) the initial redox-isomerization of the allylic alcohol, and (ii) subsequent transfer hydrogenation of the resulting carbonyl compound. The highly efficient transformation reported herein represents, not only an illustrative example of auto-tandem catalysis, but also an appealing alternative to the classical transition-metal catalyzed CC hydrogenations of allylic alcohols. The process has been successfully applied to aromatic as well as aliphatic substrates affording the corresponding saturated alcohols in 45-100% yields after 1.5-24 h. The best performances were reached using (i) 1-5 mol% of 1 or 2, 2-10 mol% of Cs2CO3, and propan-2-ol or (ii) 1-5 mol% of 1 or 2, 10-15 equivalents of NaO2CH, and water. The catalytic efficiency is strongly related to the structure of the allylic alcohol employed. Thus, in propan-2-ol, the reaction rate essentially depends on the steric requirement around the CC bond, therefore decreasing with the increasing number of substituents. On other hand, in water the transformation is favoured for primary allylic alcohols vs. secondary ones.
Cadierno, Victorio,Crochet, Pascale,Francos, Javier,Garcia-Garrido, Sergio E.,Gimeno, Jose,Nebra, Noel
scheme or table
p. 1992 - 2000
(2010/06/19)

An iron-catalysed hydrosilylation of ketones
The combination of Fe(OAc)2 and multi-nitrogen-based ligands such as N,N,N′,N′-tetramethyethylenediamine, bis-tert-butyl- bipyridine, or bis(oxazolinyl)pyridine can efficiently catalyse hydrosilylation of ketones to give the corresponding alcohols in high yields including asymmetric catalysis. The Royal Society of Chemistry.
Nishiyama, Hisao,Furuta, Akihiro
p. 760 - 762
(2007/10/03)

Ruthenium-catalyzed reduction of allylic alcohols: An efficient isomerization/transfer hydrogenation tandem process
A simple and highly efficient method for the selective reduction of the C=C bond in allylic alcohols has been developed using the ruthenium(ii) catalyst [{RuCl(μ-Cl)(η6-C6Me6)}2]. The Royal Society of Chemistry.
Cadierno, Victorio,Francos, Javier,Gimeno, Jose,Nebra, Noel
p. 2536 - 2538
(2008/02/11)

Methoxy-substituted stilbenes, styrenes, and 1-arylpropenes: Photophysical properties and photoadditions of alcohols
The photochemistry of trans-stilbene and four methoxy-substituted stilbene derivatives has been investigated in a variety of solvents. The fluorescence of all five trans isomers was quenched by 2,2,2-trifluoroethanol (TFE). Upon irradiation of the five substrates in TFE, the products derived from photoaddition of the solvent were detected. Nuclear magnetic resonance spectroscopy of the products formed by irradiation in TFE-OD indicated that the proton and nucleophile are attached to two adjacent atoms of the original alkene double bond. Irradiation of the corresponding methoxy-substituted styrenes and trans-1-arylpropenes in TFE produced the analogous solvent adducts. The photoaddition of TFE proceeded with the general order of reactivity: styre > trans-1-arylpropenes > trans-stilbenes. Transient carbocation intermediates were observed following laser flash photolysis of the stilbenes in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP). The results are consistent with a mechanism that involves photoprotonation of the substrates by TFE or HFIP, followed by nucleophilic trapping of short-lived carbocation intermediates. Compared to the other stilbene derivatives, trans-3,5-dimethoxystilbene displayed a large quantum yield of fluorescence and a low quantum yield of trans-cis isomerization in polar organic solvents. The unique photophysical properties of trans-3,5-dimethoxystilbene are attributed to formation of a highly polarized charge-transfer excited state (μe = 13.2 D).
Roberts, Jeffrey C.,Pincock, James A.
p. 1480 - 1492
(2007/10/03)

Alkylation of aldehydes with trialkylboranes in water
Water enables the alkylation of aldehydes with trialkylboranes under nickel catalysis without the addition of a base. Trialkylboranes prepared from borane-dimethyl sulfide and terminal olefins via hydroboration as well as commercially available trialkylboranes could be employed for the reaction. The reaction would proceed via η2-coordinated nickel complexes with aldehydes as the key intermediates.
Hirano, Koji,Yorimitsu, Hideki,Oshima, Koichiro
p. 1543 - 1546
(2007/10/03)

Solvent-free direct aza-Friedel-Crafts reactions between 3,4-dihydroisoquinoline and 1- or 2-naphthols
A self-catalytic aza-Friedel-Crafts method was employed to generate 1-naphtholyl tetrahydroisoquinoline products under neat conditions. In addition, a derivative was prepared in its enantiomerically pure form and has shown moderate activity for asymmetric catalysis in the asymmetric diethylzinc addition to aldehydes.
MacLeod, Patricia D.,Li, Zhiping,Feng, Jianqing,Li, Chao-Jun
p. 6791 - 6794
(2007/10/03)

The synthesis of N,O-ferrocenyl pyrrolidine-containing ligands and their application in the diethyl- and diphenylzinc addition to aromatic aldehydes
(Chemical Equation Presented) A facile route to a series of planar chiral N,O-ferrocenyl pyrrolidine-containing ligands with varying substituents at the nitrogen and oxygen donor atoms is described. The oxygen donor atom was introduced via a diastereoselective ortho-metalation of N-methylpyrrolidinyl and N-allylpyrrolidinyl ferrocene intermediates and was quenched with various ketones. The nitrogen substituent was varied through deallylation and subsequent derivatization of a secondary pyrrolidine. The efficacy of these novel ligands was investigated in the enantioselective addition of diethylzinc and diphenylzinc to aromatic aldehydes. The ligands proved highly effective in the diethylzinc addition to benzaldehyde that resulted in high yields of up to 99% and enantioselectivities (ee's) of up to 95%. The role of planar chirality was explored and the results indicated that the planar chirality, and not the central chirality, of the ferrocenyl ligands was the dominant stereo-controlling element. Employment of a mixed ethyl-phenylzinc reagent in the phenylation of aromatic aldehydes led to a mixture of the two additional products, and the phenylated product was obtained in up to 37% ee.
Ahern, Theresa,Mueller-Bunz, Helge,Guiry, Patrick J.
p. 7596 - 7602
(2007/10/03)

Unexpected formation of aryl dialkyl carbinol as a side product from the reaction of methoxyarylaldehydes with Grignard reagents
In the attempted formation of secondary aryl alkyl carbinols from the reaction of methoxyarylaldehydes with Grignard reagents, aryl dialkyl carbinols were formed as unexpected side products. A mechanism for their formation is proposed.
Sharma, Anuj,Joshi, Bhupendra P.,Singh, Narendra P.,Sinha, Arun K.
p. 847 - 851
(2007/10/03)

Synthesis and antioxidant, anti-inflammatory and gastroprotector activities of anethole and related compounds
Some derivatives of trans-anethole [1-methoxy-4-(1-propenyl)-benzene] (1) were synthesized, by introducing hydroxyl groups in the double bond of the propenyl moiety. Two types of reactions were performed: (i) oxymercuration/ demercuration that formed two products, the mono-hydroxyl derivative, 1-hydroxy-1-(4-methoxyphenyl)-propane (2) and in lesser extent the dihydroxyl derivative, 1,2-dihydroxy-1-(4-methoxyphenyl)-propane (3) and (ii) epoxidation with m-chloroperbenzoic acid that also led to the formation of two products, the dihydroxyl derivative (3) and the correspondent m-chloro-benzoic acid mono-ester, 1-hydroxy-1(4-methoxyphenyl)-2-m-chlorobenzoyl-propane (4). The structures of these compounds were confirmed mainly by mass, IR, 1H and 13C NMR spectral data. The activity of anethole and hydroxylated derivatives was evaluated using antioxidant, anti-inflammatory and gastroprotector tests. Compounds (2) and (3) were more active antioxidant agents than (1) and (4). In the anti-inflammatory assay, anethole showed lower activity than hydroxylated derivatives. Anethole and in lesser extent its derivatives 2 and 4 showed significant gastroprotector activity. All tested compounds do not alter significantly the total number of white blood cells.
Freire, Rosemayre S.,Morais, Selene M.,Catunda Jr., Francisco Eduardo A.,Pinheiro, Diana C. S. N.
p. 4353 - 4358
(2007/10/03)

Nickel-catalyzed alkylation of aldehydes with trialkylboranes
(Chemical Equation Presented) Nickel-catalyzed alkylation of aldehydes with trialkylboranes proceeds smoothly in the presence of a catalytic amount of 5-allyl-1,2,3,4,5-pentamethyl-1,3-cyclopentadiene or an excess of cesium carbonate to afford the corresponding secondary alcohols.
Hirano, Koji,Yorimitsu, Hideki,Oshima, Koichiro
p. 4689 - 4691
(2007/10/03)

Radical hydroxyalkylation of C-H bond adjacent to nitrogen of tertiary amides, ureas, and amines
Tertiary amides, ureas, and amines undergo direct intermolecular addition to aldehydes under the Et3B/air conditions, thereby providing a unique and simple means for the radical sp3 C-H transformation of nitrogen-containing molecules. Copyright
Yoshimitsu, Takehiko,Arano, Yoshimasa,Nagaoka, Hiroto
p. 11610 - 11611
(2007/10/03)

Formation and reactions of alkylzinc reagents in room-temperature ionic liquids
The presence of a suitable amount of bromide or chloride ions was found to be critical in forming the alkylzinc reagents from alkyl iodides and zinc metal in the room-temperature ionic liquid, N-butylpyridinium tetrafluoroborate. β-Hydride transfer in the reactions of butylzinc reagents with aldehydes can also be reduced by a bromide ion.
Law, Man Chun,Wong, Kwok-Yin,Chan, Tak Hang
p. 10434 - 10439
(2007/10/03)

Radical α-C-H hydroxyalkylation of ethers and acetal
(Chemical Equation Presented) Ethers and an acetal were found to undergo direct intermolecular addition to aldehydes under the Et3B/air conditions. This study presents a very unique and simple means for the radical α-C-H hydroxyalkylation of oxygen-containing compounds.
Yoshimitsu, Takehiko,Arano, Yoshimasa,Nagaoka, Hiroto
p. 2342 - 2345
(2007/10/03)