- Metal-free thermal organocatalytic pinacol coupling of arylaldehydes using an isonicotinate catalyst with bis(pinacolato)diboron
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The metal-free thermal organocatalytic pinacol coupling of arylaldehydes has been developed. The intermolecular coupling of arylaldehydes catalyzed byt-butyl isonicotinate with bis(pinacolato)diboron as the co-reducing agent afforded 1,2-diphenylethane-1,2-diols. This reaction was also applicable to the intramolecular coupling of 1,1′-biphenyl-2,2′-dicarbaldehydes to afford 9,10-dihydrophenanthrene-9,10-diols. Various functional groups were tolerated under this coupling condition.
- Hanaya, Kengo,Higashibayashi, Shuhei,Sugai, Takeshi,Yasui, Masamichi
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p. 24652 - 24655
(2021/07/29)
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- Crystal-to-Crystal Synthesis of Photocatalytic Metal–Organic Frameworks for Visible-Light Reductive Coupling and Mechanistic Investigations
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Postmodification of reticular materials with well-defined catalysts is an appealing approach to produce new catalytic functional materials with improved stability and recyclability, but also to study catalysis in confined spaces. A promising strategy to this end is the postfunctionalization of crystalline and robust metal–organic frameworks (MOFs) to exploit the potential of crystal-to-crystal transformations for further characterization of the catalysts. In this regard, two new photocatalytic materials, MOF-520-PC1 and MOF-520-PC2, are straightforwardly obtained by the postfunctionalization of MOF-520 with perylene-3-carboxylic acid (PC1) and perylene-3-butyric acid (PC2). The single crystal-to-crystal transformation yielded the X-ray diffraction structure of catalytic MOF-520-PC2. The well-defined disposition of the perylenes inside the MOF served as suitable model systems to gain insights into the photophysical properties and mechanism by combining steady-state, time-resolved, and transient absorption spectroscopy. The resulting materials are active organophotoredox catalysts in the reductive dimerization of aromatic aldehydes, benzophenones, and imines under mild reaction conditions. Moreover, MOF-520-PC2 can be applied for synthesizing gram-scale quantities of products in continuous-flow conditions under steady-state light irradiation. This work provides an alternative approach for the construction of well-defined, metal-free, MOF-based catalysts.
- Bucci, Alberto,Escudero-Adán, Eduardo C.,Gutiérrez, Luis,Kandoth, Noufal,Lloret-Fillol, Julio,Mondal, Suvendu Sekhar,Shafir, Alexandr
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- Method for preparing intermediate of chiral vicinal diamine
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The invention discloses a method for preparing an intermediate of chiral vicinal diamine. The method comprises the following steps: adding a compound IV into a solvent, stirring the compound IV and the solvent in an ice water bath, adding an initiator into the obtained reaction system, adding a reducing agent into the reaction system in batches, heating the reaction system to 20-80 DEG C, and stirring the reaction system; and extracting the reaction system after the reaction is completed, drying the obtained organic phase, filtering the dried organic phase, and performing rotary drying to obtain a compound V that is the intermediate. The preparation method of the invention has the advantages of simplicity and mild reaction conditions, and can be widely applied to industrial production.
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Paragraph 0034; 0035; 0037
(2019/01/06)
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- MeOH or H2O as efficient additive to switch the reactivity of allylSmBr towards carbonyl compounds
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A variety of carbonyl compounds were treated by allylSmBr (allylSmBr) with MeOH as the cosolvent to have further insights on the previously reported reductive coupling of aryl ketones mediated by Sm/alkyl halide/MeOH. The results demonstrate that the real reducing species in Sm/alkyl halide/MeOH system should be allylSmBr, and MeOH has elegantly switched the reactivity of allylSmBr from being nucleophilic to being good reductive coupling reagent. Besides, H2O was also found to be a useful additive to realize the pinacol coupling of aliphatic aldehydes and ketones promoted by allylSmBr.
- Li, Jianyong,Niu, Qingsheng,Li, Shanchan,Sun, Yuehao,Zhou, Qian,Lv, Xin,Wang, Xiaoxia
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supporting information
p. 1250 - 1253
(2017/03/10)
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- Selective Pinacol Coupling on Regeneratable Supported Acids in Sole Water
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Efficient pinacol coupling was developed in sole water, using a reusable heterogeneous supported acid source and zinc as cheap available metal source. This medium can be easily regenerated up to 10-fold without loss of activity. Moreover, supported acids enhance the selectivity of the pinacol coupling reaction compared with homogeneous acids.
- Sotto, Nicolas,Billamboz, Muriel,Chevrin-Villette, Carole,Len, Christophe
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p. 6375 - 6380
(2015/06/30)
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- Reductive coupling of aromatic aldehydes and acetophenone induced by TiCl4-Al/CH2(COOEt)2
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Induced by TiCl4-Al/CH2(COOEt)2 in CH 2Cl2, some aromatic aldehydes and acetophenone can afford the corresponding 1,2-diols in 13-91 % yields with good dl- diastereoselectivities within 45-60 min at room temperature.
- Song, Chang-Ying,Wang, Shu-Xiang,Chu, Wen-Hao,Li, Ji-Tai,Zhou, Zheng,Li, Hong-Yu,Cao, Zi-Qing
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p. 7993 - 7996
(2013/09/23)
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- A samarium "soluble" anode: A new source of SmI2 reagent for electrosynthetic application
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An electrochemical method to prepare solutions of samarium diiodide in THF is reported. The simple electrolysis of a samarium rod provides a rapid and straightforward in situ synthesis of SmI2. The electrogenerated complex catalyzes various C-C bond formations. The reagent is produced continuously (see scheme) and leads to efficient organic electrosynthesis with significantly smaller amounts of solvent than usually required. Copyright
- Sahloul, Kamar,Sun, Linhao,Requet, Alexandre,Chahine, Youhana,Mellah, Mohamed
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supporting information
p. 11205 - 11209,5
(2012/12/11)
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- A samarium "soluble" anode: A new source of SmI2 reagent for electrosynthetic application
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An electrochemical method to prepare solutions of samarium diiodide in THF is reported. The simple electrolysis of a samarium rod provides a rapid and straightforward in situ synthesis of SmI2. The electrogenerated complex catalyzes various C-C bond formations. The reagent is produced continuously (see scheme) and leads to efficient organic electrosynthesis with significantly smaller amounts of solvent than usually required. Copyright
- Sahloul, Kamar,Sun, Linhao,Requet, Alexandre,Chahine, Youhana,Mellah, Mohamed
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supporting information
p. 11205 - 11209
(2013/01/14)
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- Synthesis and evaluation of quinoxaline derivatives as potential influenza NS1A protein inhibitors
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A library of quinoxaline derivatives were prepared to target non-structural protein 1 of influenza A (NS1A) as a means to develop anti-influenza drug leads. An in vitro fluorescence polarization assay demonstrated that these compounds disrupted the dsRNA-NS1A interaction to varying extents. Changes of substituent at positions 2, 3 and 6 on the quinoxaline ring led to variance in responses. The most active compounds (35 and 44) had IC50 values in the range of low micromolar concentration without exhibiting significant dsRNA intercalation. Compound 44 was able to inhibit influenza A/Udorn/72 virus growth.
- You, Lei,Cho, Eun Jeong,Leavitt, John,Ma, Li-Chung,Montelione, Gaetano T.,Anslyn, Eric V.,Krug, Robert M.,Ellington, Andrew,Robertus, Jon D.
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supporting information; scheme or table
p. 3007 - 3011
(2011/06/24)
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- McMurry coupling of aryl aldehydes and imino pinacol coupling mediated by Ti(O-i-Pr)4/Me3SiCl/Mg reagent
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Ti(O-i-Pr)4/Me3SiCl/Mg reagent mediated McMurry coupling of aryl aldehydes to biaryl olefins at near room temperature. This low valent titanium (LVT) reagent also mediated the coupling of aldimines to 1,2-diamines (imino pinacol coupling).
- Okamoto, Sentaro,He, Jing-Qian,Ohno, Chihaya,Oh-iwa, Yuhji,Kawaguchi, Yuhki
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experimental part
p. 387 - 390
(2010/03/03)
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- A convenient synthesis of unsymmetrical pinacols by coupling of structurally similar aromatic aldehydes mediated by low-valent titanium
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The one-pot, selective cross pinacol-type couplings between two structurally similar aromatic aldehydes promoted by low-valent titanium generated unsymmetrical pinacols in moderate to good isolated yields in an erythrolthreo ratio of up to 91:9. This synt
- Duan, Xin-Fang,Feng, Jian-Xia,Zi, Guo-Fu,Zhang, Zhan-Bin
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experimental part
p. 277 - 282
(2009/06/24)
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- Reductive dehalogenation of arylhalides and alkylhalides with zinc in THF saturated aqueous ammonium chloride
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A low-cost and highly effective zinc/THF-saturated aqueous ammonium chloride has been developed for dehalogenation of arylhalides and alkylhalides in aqueous systems.
- Hekmatshoar, Rahim,Sajadi, Sodeh,Heravi, Majid M.
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experimental part
p. 616 - 618
(2009/05/07)
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- Pinacol coupling of aromatic aldehydes and ketones mediated by TiCl 4-Zn in ethyl acetate under ultrasound
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Zinc powder can reduce titanium tetrachloride to the corresponding low valent titanium complexes, which can promote coupling of some aromatic aldehydes and ketones to the corresponding pinacols in 35-99% yield in ethyl acetate at 20-25°C within 20-45 min under ultrasound irradiation.
- Li, Ji-Tai,Sun, Xue-Li,Lin, Zhi-Ping,Chen, Yan-Xue,Li, Tong-Shuang
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p. 1303 - 1307
(2008/09/18)
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- Pinacol coupling of aromatic aldehydes and ketones in ethyl acetate mediated by TiCl4-Mg
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Titanium tetrachloride in ethyl acetate can be reduced by Mg powder to the corresponding low-valent titanium complexes, which can reduce some aromatic aldehydes and ketones to the corresponding pinacols in 38-85% yields within 15-60 min at rt with stirring. Copyright Taylor & Francis Group, LLC.
- Wang, Ke,Wang, Shu-Xiang,Gao, Ming-Zhu,Li, Ji-Tai
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p. 1391 - 1399
(2007/10/03)
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- Novel and efficient Ni-mediated pinacol coupling of carbonyl compounds
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It was firstly found that the Rieke Ni generated in situ was able to promote the pinacol coupling of various carbonyls efficiently. Based on this information, another catalytically effective, cheaper and more convenient NiCl2(Cat.)/Mg/TMSCl system was designed and developed further successfully. The interesting single-electron transfer (SET) mechanisms for the coupling reactions were proposed. Additionally, the DL/meso diastereoselectivity and some additive effects were also explained in terms of the proposed mechanisms.
- Shi, Lei,Fan, Chun-An,Tu, Yong-Qiang,Wang, Min,Zhang, Fu-Min
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p. 2851 - 2855
(2007/10/03)
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- Stereoselectivity in Pinacol-Homocoupling Mediated by Samarium Diiodide
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The stereoselectivity of the pinacol-coupling of various substituted benzaldehydes mediated by samarium diiodide was investigated. The dependence of product-ratios, yields, and stereoselectivities on the substrate, the substrate-reagent-ratio, and the solvent is described.
- Gaertner, Peter,Knollmueller, Max,Broeker, Joachim
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p. 1607 - 1615
(2007/10/03)
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- Asymmetric synthesis of anti- and syn-β-amino alcohols by reductive cross-coupling of transition metal-coordinated planar chiral arylaldehydes with aldimines
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Samarium iodide-mediated cross-coupling of N-tosyl ferrocenylideneamine with planar chiral ferrocenecarboxaldehydes or benzaldehyde chromium complexes gave diastereoselectively the corresponding anti-β-amino alcohol derivatives in good yields, while N-tosyl benzylideneamine produced syn-β-amino alcohols by coupling with planar chiral arylaldehydes. Dynamic kinetic resolution of a configurationally equilibrated reactive species generated from achiral N-tosyl ferrocenilideneamine and benzylideneamine by reduction with samarium iodide was observed in the cross-coupling with planar chiral arylaldehydes giving both antipodes of β-amino alcohols depending on the planar chirality. The obtained anti-β-amino alcohol with the ferrocene ring was utilized as a chiral ligand for catalytic asymmetric reduction of acetophenone.
- Tanaka, Yoshie,Taniguchi, Nobukazu,Kimura, Takayuki,Uemura, Motokazu
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p. 9227 - 9237
(2007/10/03)
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- Asymmetric synthesis of β-amino alcohols by reductive cross-coupling of benzylideneamine with planar chiral benzaldehydes
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(equation presented) Samarium iodide mediated reductive cross-coupling of N-tosyl benzylideneamine with benzaldehydes or the corresponding chromium complexes gave syn-β-amino alcohol derivatives. A dynamic kinetic resolution of a configurationally equilibrated reactive species occurred in the cross-coupling with planar chiral benzaldehyde chromium complexes.
- Tanaka, Yoshie,Taniguchi, Nobukazu,Uemura, Motokazu
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p. 835 - 838
(2007/10/03)
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- Reductive coupling of carbonyl compounds to pinacols with zinc in THF-saturated aqueous ammonium chloride
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In the presence of metallic zinc, aldehydes and ketones experience reductive coupling in tetrahydrofuran-saturated aqueous ammonium chloride (5:3) to afford the corresponding pinacols in moderate to high yields.
- Hekmatshoar,Yavari,Beheshtiha,Heravi
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p. 689 - 691
(2007/10/03)
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- Improved synthesis and crystal structure of TiCl3(tmeda)(thf): A highly stereoselective pinacol coupling reagent for aromatic aldehydes
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A monomeric titanium(III) complex, TiCl3(tmeda)(thf) (1), has been prepared by a reaction of TiCl4 with TMEDA, Zn, and a catalytic amount of PbCl2 in an almost quantitative yield. The solid state structure of 1 is revealed by X-ray crystallographic analysis. The complex 1 couples aromatic aldehydes under mild conditions to give 1,2-diols in good to excellent yields with high d/-selectivities.
- Oshiki, Toshiyuki,Kiriyama, Takayuki,Tsuchida, Kazuaki,Takai, Kazuhiko
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p. 334 - 335
(2007/10/03)
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- The effect of Lewis acids on the pinacol homocoupling reaction of aldehydes promoted by samarium diiodide
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The effect of various Lewis acids on the samarium diiodide promoted pinacol homocoupling of aldehydes was investigated. The reaction of benzaldehyde proceeded with fair to good 1,2-anti-stereoselectivity, while in the case of other aromatic and aliphatic aldehydes syn-stereoselectivity was generally observed. Chiral α-alkylaldehydes allowed for an almost complete stereocontrol favoring syn-1,2-diols.
- Annunziata, Rita,Benaglia, Maurizio,Cinquini, Mauro,Raimondi, Laura
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p. 3369 - 3374
(2007/10/03)
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- Studies on oxygen heterocycles part 2: Synthesis of 2-arylcoumaranones and 2-phenylbenzofuran
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The synthesis of 2-arylcoumaranones and 2-phenyllbenzofuran has been achieved in good yields under acid catalysed conditions from readily accessible and suitably substituted aryl α-diazo-arylmethyl ketones.
- Ghosh, Somnath,Banerjee, Indira,Baul, Susmita
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p. 11537 - 11546
(2007/10/03)
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- Stereoselective pinacol coupling of planar chiral (benzaldehyde)Cr(Co)3, (benzaldimine)Cr(CO)3, ferrocenecarboxaldehyde and (dienal)Fe(CO)3 complexes with samarium diiodide
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An intermolecular pinacol coupling of the Planar chiral tricarbonylchromium complexes of o-substituted benzaldehydes or benzaldimines with samarium(II) diiodide in THF produces exclusively threo 1.2-diols or 1,2-diamines in an optically pure form, while the corresponding racemic o- substituted benzaldehyde or benzaldimine chromium complexes give a mixture of threo and erythro pinacol coupling products in a various ratio depending upon the nature of o-substituent. Similarly, planar chiral 2-substituted ferrocenecarboxaldehydes and (dienal)Fe(CO)3 produce the corresponding 1.2- diols with high stereoselectivity. The generated transition metal-complexed ketyl radical intermediates are configurationally stable with restriction to a rotation about C(α)-C(ipso) bond.
- Taniguchi, Nobukazu,Uemura, Motokazu
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p. 12775 - 12788
(2007/10/03)
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- Coupling of fluoroform with aldehydes using an electrogenerated base
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Trifluoromethylated alcohols are easily obtained in a one pot electroreaction in which cathodic reduction of iodobenzene generates a strong base which deprotonates fluoroform, inducing its coupling with aldehydes.
- Barhdadi, Rachid,Troupel, Michel,Perichon, Jacques
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p. 1251 - 1252
(2007/10/03)
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- Reductive coupling of carbonyl compounds to pinacols by using Sm-I2MeOH or Sm-I2-Ti(O(i)Pr)4-MeOH systems
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The coupling reaction of aromatic carbonyl compounds was performed with Sm-I2 or Sm-I2-Ti(O(i)Pr)4 in methanol. Meso isomer was mainly produced in the presence of Ti(O(i)Pr4.
- Yanada, Reiko,Negoro, Nobuyuki,Yanada, Kazuo,Fujita, Tetsuro
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p. 3271 - 3274
(2007/10/03)
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- Pinacolic coupling of aromatic carbonyl compounds using Zn powder in aqueous basic media without organic solvents
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Treatment of aromatic carbonyl compounds with Zn powder in 10% aq NaOH solution without using any organic solvents under the mild conditions afforded the corresponding 1,2-diols in good yields.
- Tsukinoki, Takehito,Kawaji, Takatoshi,Hashimoto, Iwao,Mataka, Shuntaro,Tashiro, Masashi
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p. 235 - 236
(2007/10/03)
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- Pinacolization and reduction of aromatic carbonyls with aluminium-KOH
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A simple and rapid procedure for the pinacolization of aromatic aldehydes and reduction of hindered ketones with inexpensive aluminium and KOH in methanol at ambient temperature is reported. The pinacolization and reduction are proposed to be proceeding via single electron transfer from aluminium. Copyright 1996 by the Royal Society of Chemistry.
- Khurana, Jitender M.,Sehgal, Arti,Gogia, Amita,Manian, Aparna,Maikap, Golak C.
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p. 2213 - 2215
(2007/10/03)
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- Heterodiene cycloadditoins of C2 symmetric 4,5-disubstituted ketene acetals: the nett asymmetric conjugate addition of recyclable acetic ester enolate equivalents to an activated enone
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Heterodiene cycloadditions of 3-formylchromone 2 to a series of ketene acetals 1 derived from C2 symmetric 1,2-diarylethane-1,2-diols are diastereoselective.From (S,S)-1,2-di(o-tolyl)ethane-1,2-diol 6c the major cycloadduct 3c was isolated by crystallization and transformed by acid-catalysed methanolysis into (S)-methyl 4-oxo-3,4-dihydro-2H-1-benzopyran-2-ylacetate 5, together with the original 1,2-diol 6c which could be recycled.The structures of two cyclic carbonates 22a and 22c were determined by X-ray diffraction and used as models in seeking a mechanistic rationale for the stereoselective cycloadditions of the analogous ketene acetals 1a and 1c.
- Wallace, Timothy W.,Wardell, Ian,Li, Ke-Dong,Leeming, Peter,Redhouse, Alan D.,Challand, S. Richard
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p. 2293 - 2308
(2007/10/02)
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- PHOTOCHEMICAL REACTION OF ALCOHOLS - II. IRRADIATION OF AROMATIC ALCOHOLS
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The UV irradiation of aromatic alcohols leads to the formation of several products: carbonyl compounds, ethers, α-glycols and tetra-aryl-1,4-dioxanes.The photoformation of α-glycols is qualitatively and quantitatively compared to the photoreduction of the carbonyl compounds.It is noteworthy that the glycols are formed with a stereochemistry very different depending upon whether the substrate is an alcohol or a carbonyl compound.The structure, configuration and conformation of the 1,4-dioxanes obtained are studied as well as their origin.Other aspects of the photochemistry of the alcohols are analyzed using hydroperoxides as model substrates.
- Balsells, R. Erra,Frasca, A. R.
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p. 2525 - 2538
(2007/10/02)
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