- Unusual sulfanylation through ring transformation of arene-tethered 2H-pyran-2-ones by in situ built Michael adduct
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A novel synthesis of highly functionalized alkylsulfanylmethyl arenes 8a-m through the ring transformation of 6-aryl-4-methyl/ethylsulfanyl-2H-pyran-2-one-3-carbonitriles 1a-j, by reaction with methyl vinyl ketone 2, is delineated and illustrated. To asce
- Sil, Diptesh,Pratap, Ramendra,Kumar, Rishi,Maulik,Ram, Vishnu Ji
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Read Online
- A mild and chemoselective CALB biocatalysed synthesis of sulfoxides exploiting the dual role of AcOEt as solvent and reagent
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A mild, chemoselective and sustainable biocatalysed synthesis of sulfoxides has been developed exploiting CALB and using AcOEt with a dual role of more environmentally friendly reaction solvent and enzyme substrate. A series of sulfoxides, including the drug omeprazole, have been synthesised in high yields and with excellent E-factors.
- Anselmi, Silvia,Liu, Siyu,Kim, Seong-Heun,Barry, Sarah M.,Moody, Thomas S.,Castagnolo, Daniele
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supporting information
p. 156 - 161
(2021/01/14)
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- Photo-Biocatalytic Cascades for the Synthesis of Volatile Sulfur Compounds and Chemical Building Blocks
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Biocatalysis is a branch of catalysis that exploits enzymes to perform highly stereoselective chemical transformations under mild and sustainable conditions. This Synpact highlights how biocatalysis can be used in the synthesis of chiral 1,3-mercaptoalkan
- Castagnolo, Daniele,Lauder, Kate
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p. 737 - 744
(2020/05/19)
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- Photo-biocatalytic One-Pot Cascades for the Enantioselective Synthesis of 1,3-Mercaptoalkanol Volatile Sulfur Compounds
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The synthesis of enantiomerically pure 1,3-mercaptoalkanol volatile sulfur compounds through a one-pot photo-biocatalytic cascade reaction is described. Two new KRED biocatalysts with opposite enantioselectivity were discovered and proved to be efficient
- Lauder, Kate,Toscani, Anita,Qi, Yuyin,Lim, Jesmine,Charnock, Simon J.,Korah, Krupa,Castagnolo, Daniele
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supporting information
p. 5803 - 5807
(2018/04/19)
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- Enantioselective Synthesis of Quaternary Δ4- and Δ5-Dehydroprolines Based on a Two-Step Formal [3+2] Cycloaddition of α-Aryl and α-Alkyl Isocyano(thio)acetates with Vinyl Ketones
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A divergent synthesis of optically active quaternary Δ4- and Δ5-dehydro prolines is developed based on the first catalytic enantioselective conjugate addition of α-substituted isocyano(thio)acetates to vinyl ketones that is general for both α-aryl and α-alkyl isocyano(thio)acetates. The new tetrasubstituted C?N stereocenter is formed without the need of any metal salt due to a bifunctional tertiary amine/squaramide catalyst, featuring a bulky polyaryl sidearm and an unusually short squaramide diamide H???H interatomic distance in the solid state.
- Odriozola, Amaiur,Oiarbide, Mikel,Palomo, Claudio
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supporting information
p. 12758 - 12762
(2017/09/25)
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- Functionalized α-oximinoketones as building blocks for the construction of imidazoline-based potential chiral auxiliaries
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Functionalized α-oximinoketones with β-alkoxy, β-alkyl, and β-sulfenyl groups were used as efficient synthons for the preparation of chiral 1-acyl-4-imidazolin-2-ones and 1-acylimidazolidin-2-ones. For the preparation of the former heterocycles, α-oximinoketones were transformed into their respective imidazole N-oxides by neutral treatment with a chiral triazine, followed by reaction with acetic or propionic anhydrides to furnish the desired chiral 1-acetyl- or 1-propionyl-4-imidazolin-2-ones in moderate overall yields. Upon palladium hydroxide-catalyzed hydrogenation, these series were converted into their corresponding 1-acylimidazolidin-2-ones in high diastereoisomeric ratios. Thus, these novel chiral 1-acetyl- and 1-propionyl-imidazolidin-2-ones were obtained with a variety of alkyl groups at the C-4 and C-5 positions of the heterocycle, through a three-step methodology, and can be applied as new potential chiral auxiliaries.
- Gutiérrez, Rsuini U.,Rebollar, Araceli,Bautista, Rafael,Pelayo, Vanessa,Várgas, José Luis,Montenegro, Mabel M.,Espinoza-Hicks, Carlos,Ayala, Francisco,Bernal, Pablo M.,Carrasco, Cuauhtemoc,Zepeda, L. Gerardo,Delgado, Francisco,Tamariz, Joaquín
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p. 230 - 246
(2015/03/04)
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- N-heterocyclic carbene catalyzed carba-, sulfa-, and phospha-Michael additions with NHC·CO2 adducts as precatalysts
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N-heterocyclic carbene catalyzed Michael additions have been revisited with 1,3-dialkyl- or 1,3-diarylimidazol(in)ium-2-carboxylates, that is, NHC·CO2 adducts, as the source of the free NHC catalysts in solution. Using these precatalysts, a number of efficient carba-, sulfa-, and phospha-Michael additions were achieved very conveniently, without the need for an external strong base to generate the NHC by deprotonation of an azolium salt. To further expand the scope of the procedure, some NHC-catalyzed sulfa-Michael/aldol organocascades were also investigated.
- Hans, Morgan,Delaude, Lionel,Rodriguez, Jean,Coquerel, Yoann
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p. 2758 - 2764
(2014/04/17)
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- PYRONE COMPOUNDS AND HERBICIDES COMPRISING THE SAME
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The present invention provides a compound having an excellent efficacy for controlling weeds. A pyrone compound of formula (I): wherein m is 1, 2 or 3; n is an integer of any one of 1 to 5; X represents O, S, S(O) or S(O)2; R1 repres
- -
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Paragraph 0062
(2014/05/07)
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- Selectivity reversal during thia-Michael additions using tetrabutylammonium hydroxide: Operationally simple and extremely high turnover
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The use of tetrabutylammonium hydroxide as a novel and exceedingly efficient thia-Michael addition catalyst is herein described. This extremely simple methodology allows for the conjugate addition of a wide variety of mercaptan nucleophiles, and functions remarkably well with a very wide range of both classical and non-classical Michael acceptors. Contradistinctive to current literature reports, the use of this catalyst more efficiently promotes the addition of more basic thiols. This methodology is especially attractive and operationally simple, as it generally proceeds with only 1 mol% catalytic loading and without excess reagent, and the produced products typically require no purification. Georg Thieme Verlag Stuttgart New York.
- Nicponski, Daniel R.,Marchi, Jennifer M.
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supporting information
p. 1725 - 1730
(2014/07/08)
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- O-benzenedisulfonimide as a reusable brnsted acid catalyst for hetero-michael reactions
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The hetero-Michael reactions among various oxygen, sulfur, and nitrogen nucleophiles and ,-unsaturated compounds were carried out in the presence of catalytic amounts of o-benzenedisulfonimide as Brnsted acid organocatalyst. The reaction conditions were very mild, and the yields of target products were good. The catalyst was easily recovered and purified, ready to be used in further reactions. This ability grants economic and ecological advantages. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
- Barbero, Margherita,Cadamuro, Silvano,Dughera, Stefano
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p. 758 - 767
(2013/01/15)
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- Ionic liquid/PPh3 promoted cleavage of diphenyl disulfide and diselenide: A straight-forward metal-free one-pot route to the synthesis of unsymmetrical sulfides and selenides
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A metal-free cleavage of diphenyl disulfide and diphenyl diselenide has been achieved using ionic liquid/triphenyl phosphine (PPh3) and a convenient protocol for the one-pot synthesis of unsymmetrical sulfides and selenides by condensing 'in situ' generated thiolate or selenate anion with alkyl halides has been developed. In addition, 1,4-conjugate addition of the generated thiolate anions to activated alkenes has also been demonstrated. The ionic liquid, 1-methyl-3-pentyl imidazolium bromide, [pmIm]Br plays a crucial role in promoting the course of the reactions and shows superior activity and selectivity compared to other solvents. The [pmIm]Br has been reused for at least five times without appreciable loss of activity.
- Banerjee, Subhash,Adak, Laksmikanta,Ranu, Brindaban C.
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supporting information; experimental part
p. 2149 - 2152
(2012/05/05)
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- Anodic generation of a zirconium catalyst for Ferrier rearrangement and hetero Michael addition
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An efficient catalyst for Ferrier rearrangement and hetero-Michael addition was successfully generated from a sacrificial zirconium anode into media containing reactants for these reactions. Thus, the catalyst generated, successfully promoted the allylic
- Stevanovic, Dragana,Pejovic, Anka,Damljanovic, Ivan,Vukic evic, Rastko D.,VukiC evic, Mirjana,Bogdanovic, Goran A.
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p. 6257 - 6260,4
(2012/12/11)
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- Squaric acid as an impressive organocatalyst for Michael addition in water
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A simple, green, and environmentally benign protocol for squaric acid (5 mg) catalyst conjugate addition of aromatic amines and thiols to unsaturated carbonyl compounds in water in good to excellent yields is developed. The advantages of low sensitivity toward moisture and oxygen, high tolerance of different functional groups, green reaction media and efficient recyclability make this organocatalyst suitable for both laboratory and industrial scale synthesis of β-substituted carbonyls under very mild conditions.
- Azizi, Najmadin,Saki, Elham,Edrisi, Mahtab
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experimental part
p. 973 - 977
(2012/05/20)
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- Synthesis and application of modified silica sulfuric acid as a solid acid heterogeneous catalyst in Michael addition reactions
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Figure represented. Modified silica sulfuric acid (MSSA) as a new type of silica sulfuric acid was prepared and effectively used in the conjugate addition of indole, pyrrole, and thiols with Michael acceptors under mild conditions at room temperature. Als
- Zolfigol, Mohammad Ali,Veisi, Hojat,Mohanazadeh, Farajollah,Sedrpoushan, Alireza
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experimental part
p. 977 - 986
(2011/09/16)
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- α-Sulfonyl succinimides: Versatile sulfinate donors in Fe-catalyzed, salt-free, neutral allylic substitution
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Allyl sulfones are versatile intermediates in organic chemistry. The presence of two distinct functional groups sets the stage for a plethora of subsequent transformations. However, despite these advantages the preparation of regioisomerically enriched sulfones is not easy. The use of sulfinate salts as nucleophiles in substitutions is frequently accompanied by side reactions such as π-bond migration, β-elimination, and so on. Herein we present a preparatively simple way to synthesize a variety of different aryl or alkyl allyl sulfones starting from readily accessible allylic carbonates. By employing aryl or alkyl α-sulfonyl succinimides as sulfinate synthons, mild and regioselective ipso substitution of diverse allylic carbonates was realized.
- Jegelka, Markus,Plietker, Bernd
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supporting information; experimental part
p. 10417 - 10430
(2011/10/31)
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- Supported cobalt complex-catalysed conjugate addition of indoles, amines and thiols to α,β-unsaturated compounds
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A highly active and reusable supported Co(ii) complex on SBA-15 shows an excellent activity and selectivity to target products in aza- and thia-Michael conjugate additions of indoles, amines and thiols to α,β-unsaturated compounds under solventless mild reaction conditions. The Co-catalyst was also highly reusable and comparably more active than related catalysts in the reaction.
- Rajabi, Fatemeh,Razavi, Sepideh,Luque, Rafael
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experimental part
p. 786 - 789
(2010/09/05)
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- Silica nanoparticles as a reusable catalyst: A straightforward route for the synthesis of thioethers, thioesters, vinyl thioethers and thio-Michael adducts under neutral reaction conditions
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A simple and straightforward route for the synthesis of thioethers, thioesters, vinyl thioethers and thio-Michael adducts has been demonstrated using silica nanoparticles (NPs) as a reusable catalyst via the 1,2-addition of thiols to alkenes, alkynes and alkyl/acyl halides, and the 1,4-addition of thiols to conjugated alkenes at room temperature.
- Banerjee, Subhash,Das, Jayanta,Alvarez, Richard P.,Santra, Swadeshmukul
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experimental part
p. 302 - 306
(2010/06/13)
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- "On-water" conjugate additions of anilines
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The conjugate addition of anilines onto unsaturated ketones, esters and N-acylpyrroles was investigated. Based on a recently proposed explanation for the phenomenon of on-water catalysis, operationally simple and mild reaction conditions for effecting these addition reactions have been developed. The success of these additions provides further support for the acid-catalysed nature of on-water chemistry.
- Phippen, Christopher B. W.,Beattie, James K.,McErlean, Christopher S. P.
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supporting information; experimental part
p. 8234 - 8236
(2010/12/20)
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- Efficient synthesis of vinyl and alkyl sulfides via hydrothiolation of alkynes and electron-deficient olefins using soluble and heterogenized gold complexes catalysts
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Soluble and heterogenized gold complexes catalyze the hydrothiolation of alkynes and electron-deficient olefins in high yields and with high anti-Markovnikov selectivity. Moreover heterogenized catalysts could be recycled in several successive runs withou
- Corma, Avelino,González-Arellano, Camino,Iglesias, Marta,Sánchez, Félix
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experimental part
p. 49 - 54
(2010/08/06)
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- Reduction cleavage of S-S bond by Zn/Cp2tiCl2: Application for the synthesis of β-arylthiocarbonyl compounds
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Diaryl disulfides were reduced efficiently by a Zn/Cp2TiCl 2 system at room temperature in dry THF to give the corresponding nucleophilic sulfur anion-titanocene complex, followed by reaction with α, β-unsaturated esters (ketones or nitriles) to afford the corresponding β-arylthioesters(ketone or nitrile) in good yields.
- Xu, Xiao Bo,Yin, Xian Hong,Zhu, Yu Yang,Xu, Xin Hua,Luo, Tao,Li, Yin Hui,Lu, Xiong,Shao, Ling Ling,Pan, Jian Gao,Yang, Rong Hua
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experimental part
p. 750 - 752
(2010/03/24)
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- Triethylammonium acetate (TEAA): A recyclable inexpensive ionic liquid promotes the chemoselective aza- and thia-Michael reactions
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A new, highly efficient, inexpensive, recyclable, mild, convenient, and green protocol for chemoselective aza/thia-Michael addition reactions of amines/thiols to α,β-unsaturated compounds using triethylammonium acetate (TEAA) ionic liquid was developed. The catalyst can be recycled ten times and obviate the need for toxic and expensive catalysts.
- Verma, Akhilesh K.,Attri, Pankaj,Chopra, Varun,Tiwari, Rakesh K.,Chandra, Ramesh
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experimental part
p. 1041 - 1047
(2009/11/30)
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- Fluoroboric acid adsorbed on silica-gel (HBF4-SiO2) as a new, highly efficient and reusable heterogeneous catalyst for thia-Michael addition to α,β-unsaturated carbonyl compounds
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Fluoroboric acid adsorbed on silica-gel (HBF4-SiO2) has been found to be a new and highly efficient heterogeneous catalyst for thia-Michael addition to α,β-unsaturated carbonyl compounds under solvent-free conditions. In the case of
- Sharma, Gaurav,Kumar, Raj,Chakraborti, Asit K.
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p. 4272 - 4275
(2008/09/21)
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- New, general, and practical preparation of methyl ketones via the direct coupling of amides with CH2CI2 promoted by TiCI 4/Mg
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The direct coupling of a variety of amides with CH2CI 2 or CD2CI2 promoted by TiCI4/Mg/THF provides an extremely simple, practical, selective, and efficient approach for the construction of methyl ketones. The efficiency and practicability of this chemistry is illustrated by the very simple synthesis of deuterated methyl ketones.
- Lin, Kuo-Wei,Tsai, Chi-Hui,Hsieh, L-Lin,Yan, Tu-Hsin
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supporting information; experimental part
p. 1927 - 1930
(2009/04/10)
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- Efficient synthesis of β-alkyl/arylsulfanyl carbonyl compounds by In-TMSCl-promoted cleavage of dialkyl/diaryl disulfides and subsequent Michael addition
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A convenient and efficient procedure for the synthesis of β-alkyl/arylsulfanyl carbonyl compounds has been developed by a simple one-pot reaction of dialkyl/diaryl sulfides with α,β-unsaturated aldehydes, ketones, carboxylic esters, and nitriles in presence of indium and trimethylsilyl chloride under sonication. Copyright Taylor & Francis Group, LLC.
- Ranu, Brindaban C.,Mandal, Tanmay
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p. 1517 - 1523
(2008/02/03)
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- Ceric ammonium nitrate (CAN) as a green and highly efficient promoter for the 1,4-addition of thiols and benzeneselenol to α,β-unsaturated ketones
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A mild and efficient process for the 1,4-addition of thiols and benzeneselenols to various α,β-unsaturated ketones using a catalytic amount of CAN with excellent product yields is described. This inexpensive, nontoxic, and readily available catalytic ceric(IV) ammonium nitrate system efficiently catalyzes conjugate addition reactions between thiol derivatives and various α,β-unsaturated ketones under solvent-free conditions. A plausible mechanism for the role of CAN, both as a promoter in free radical chain addition reactions as well as a catalyst for the conjugate addition process is proposed.
- Chu, Cheng-Ming,Gao, Shijay,Sastry,Kuo, Chun-Wei,Lu, Chaowei,Liu, Ju-Tsung,Yao, Ching-Fa
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p. 1863 - 1871
(2007/10/03)
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- Amino acid catalyzed thio-Michael addition reactions
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Using amino acid as a catalyst, an inexpensive, nontoxic, environmentally friendly, metal-free reaction procedure for C-S bond formation via thio-Michael addition reaction has been developed. The thio-Michael addition products were obtained in excellent yields under mild and neutral conditions. This metal-free catalytic protocol was found to be a good alternative to the existing metal catalyst methodology for the thio-Michael addition reaction.
- Kumar, Atul,Akanksha
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p. 11086 - 11092
(2008/02/12)
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- Scope and limitations of HClO4-SiO2 as an extremely efficient, inexpensive, and reusable catalyst for chemoselective carbon-sulfur bond formation
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The scope and limitations of perchloric acid adsorbed on silica gel (HClO4-SiO2) as a highly efficient, inexpensive, and reusable catalyst for chemoselective carbon-sulfur bond formation by conjugate addition of thiols to α,β-unsatur
- Khatik, Gopal L.,Sharma, Gaurav,Kumar, Raj,Chakraborti, Asit K.
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p. 1200 - 1210
(2007/10/03)
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- A simple, efficient, and green procedure for the 1,4-addition of thiols to conjugated alkenes and alkynes catalyzed by sodium acetate in aqueous medium
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A benign and inexpensive salt, sodium acetate, efficiently catalyzes 1,4-addition of thiols to a variety of conjugated alkenes such as ?,?-unsaturated ketones, aldehydes, carboxylic esters, nitriles, nitro compounds, and chalcones in aqueous THF. The reac
- Ranu, Brindaban C.,Mandal, Tanmay
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p. 223 - 227
(2008/02/10)
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- Stereoselective biocatalytic synthesis of (S)-2-hydroxy-2-methylbutyric acid via substrate engineering by using "thio-disguised" precursors and oxynitrilase catalysis
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3-Tetrahydrothiophenone (4) and 4-phenylthiobutan-2-one (7) were used as masked 2-butanone equivalents to give the corresponding cyanohydrins 5 (79% yield, 91% ee) and 8 (95% yield, 96% ee) in an enzymatic cyanohydrin reaction applying the hydroxynitrile
- Fechter, Martin H.,Gruber, Karl,Avi, Manuela,Skranc, Wolfgang,Schuster, Christian,Poechlauer, Peter,Klepp, Kurt O.,Griengl, Herfried
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p. 3369 - 3376
(2008/01/06)
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- Indium(I) iodide promoted cleavage of dialkyl disulfides - Application of the Michael addition of thiolate anions to conjugated carbonyl compounds and regioselective ring opening of epoxides
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Indium(I) iodide promotes cleavage of dialkyl disulfides generating thiolate anions that then undergo facile addition to α,β-unsaturated ketones, aldehydes, carboxylic esters, and nitriles under neutral conditions producing corresponding β-ketosulfides or β-cyanosulfides. This strategy has also been used for the regioselective nucleophilic ring opening of epoxides by thiolate anions in presence of indium(III) chloride producing corresponding β-hydroxyphenyl sulfides. The reactions are in general, very clean, high yielding, and reasonably fast. Thus, simple and convenient procedures for the synthesis of β-ketosulfides or β-cyanosulfides and β-hydroxyalkyl sulfides have been developed using this cleavage reaction.
- Ranu, Brindaban C.,Mandal, Tanmay
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p. 762 - 770
(2007/10/03)
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- Formation of zinc thiolates by reductive cleavage of disulfides with the Zn/AlCl3 system in aqueous media, and their use for Michael addition
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A simple, convenient, and efficient one-pot protocol for the reductive cleavage of disulfides and Michael addition to α,β-unsaturated carbonyl compounds mediated by the Zn/AlCl3 system in aqueous media is reported.
- Movassagh, Barahman,Zakinezhad, Yousef
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- [HP(HNCH2CH2)3N]NO3: An efficient homogeneous and solid-supported promoter for aza and thia-Michael reactions and for Strecker reactions
-
In the presence of a catalytic amount of an azaphosphatrane nitrate salt, amines and thiols react readily with Michael acceptors. The salt is also an efficient promoter for the one pot synthesis of α-amino and α-amidonitriles. By anchoring the salt to Merrifield Resin, a reusable heterogeneous catalyst is obtained for these reactions. Evidence is presented for catalysis being attributable solely to the NO3- ion.
- Fetterly, Brandon M.,Jana, Nirmal K.,Verkade, John G.
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p. 440 - 456
(2007/10/03)
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- Synthesis of novel β-functionalized α-oximinoketones via hetero-Michael addition of alcohols and mercaptans to enones
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A new methodology has been developed for the preparation of β-alkoxy and β-sulfenyl ketones by hetero-Michael addition of the corresponding alcohols and thiols to enones under acidic and basic conditions. The direct conversion of enones into β-alkoxy and
- Bernal, Pablo,Tamariz, Joaquín
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p. 2905 - 2909
(2007/10/03)
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- L-proline catalyzed michael additions of thiophenols to α,βunsaturated compounds, particularly α-enones, in the ionic liquid [bmim]PF6
-
L-Proline catalyzed additions of 13 different thiols to 11 different a-enone Michael acceptors in [bmim] PF6 are reported. Reasonable to high yields of the reaction products were isolated in most cases.
- Kotrusz, Peter,Toma, Stefan
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p. 197 - 205
(2007/10/03)
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- Catalyst-free conjugated addition of thiols to α,β-unsaturated carbonyl compounds in water
-
Catalyst-free conjugate addition of thiols to α,β-unsaturated carbonyl compounds in water is reported. β-Sulfido carbonyl compounds were formed at room temperature, in short times and with excellent chemoselectivity. Competitive dithiane/dithiolane format
- Khatik, Gopal L.,Kumar, Raj,Chakraborti, Asit K.
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p. 2433 - 2436
(2007/10/03)
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- The iron(III) chloride-mediated 1,4-addition of mercaptans to α,β-unsaturated ketones and esters under solvent free conditions
-
The 1,4-addition of various thiols to α,β-unsaturated ketones was completed rapidly in the presence of a catalytic amount (2-3 mol %) of anhydrous iron(III) chloride under solvent free conditions and an air atmosphere. Anhydrous iron(III) chloride is more active than that of other ferric salts. With more reactive and/or less steric reagents (1a-c and/or 2a-2c), expeditious conditions (short reaction times at room temperature) could be employed. With less reactive and/or steric reagents (1d-g and/or 2d-e), a slight increase in reaction time was required, but high yields were obtained. The FeCl3 catalyst causes preferential interactions with α,β-unsaturated ketones present in the reaction.
- Chu, Cheng-Ming,Huang, Wan-Ju,Lu, Chaowei,Wu, Pohsi,Liu, Ju-Tsung,Yao, Ching-Fa
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p. 7375 - 7380
(2007/10/03)
-
- The ionic liquid ethyltri-n-butylphosphonium tosylate as solvent for the acid-catalysed hetero-Michael reaction
-
A new and convenient method for the acid-catalysed Michael addition reactions of alcohols, thiols and amines to methyl vinyl ketone has been developed using the ionic liquid ethyltri-n-butylphosphonium tosylate. The reaction conditions are mild and obviat
- Karodia, Nazira,Liu, Xihan,Ludley, Petra,Pletsas, Dimitrios,Stevenson, Grace
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p. 11039 - 11043
(2007/10/03)
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- Liquid/liquid separation of polysiloxane-supported catalysts
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Liquid/liquid separation after monophasic reactions is a viable way to use and recover polysiloxane-supported catalysts. The Royal Society of Chemistry 2006.
- Grunlan, Melissa A.,Regan, Katherine R.,Bergbreiter, David E.
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p. 1715 - 1717
(2008/10/09)
-
- Improved heteroatom nucleophilic addition to electron-poor alkenes promoted by CeCl3·7H2O/NaI system supported on alumina in solvent-free conditions
-
(Chemical Equation Presented). Conjugate addition of heteroatom nucleophiles to carbon-carbon double bonds conjugated with a strong electron-withdrawing group is one of the most important new bond-forming strategies in synthetic organic chemistry. Among the methods for these Michael additions, Lewis acids have shown the best promoter activity, and in particular, the use of reagents impregnated over inorganic supports is rapidly increased. With the increase of environmental consciousness in chemical research, the solvent-free Michael addition has attracted our attention. In continuation of our ongoing program to develop synthetic protocols utilizing cerium trichloride, we report an extension of the CeCl3·7H2O/NaI combination supported under solvent-free conditions to promote heteroatom Michael addition. Using neutral alumina (Al2O3) as solid support permits us to circumvent some of the problems associated with the procedure where the inorganic support is silica gel. The CeCl 3· 7H2O/NaI/Al2O3 system works well for hetero-Michael additions utilizing weakly nucleophiles such as imidazoles and carbamates, and also the reaction proceeds with good yields in the case of Michael acceptors different from α,β-unsaturated carbonyl compounds. An important synthetic application of this our methodology is the intramolecular aza-Michael reaction in producing 4-piperidinone derivatives, which are of interest as synthetic intermediates toward important classes of heterocycles.
- Bartoli, Giuseppe,Bartolacci, Massimo,Giuliani, Arianna,Marcantoni, Enrico,Massaccesi, Massimo,Torregiani, Elisabetta
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p. 169 - 174
(2007/10/03)
-
- Study of the Michael addition of β-cyclodextrin-thiol complexes to conjugated alkenes in water
-
An environmentally benign and highly efficient supramolecular Michael addition of thiols from the secondary side of β-cyclodextrin to α,β-unsaturated compounds at the primary side in water is described in quantitative yields; products of undesirable side
- Krishnaveni, N. Srilakshmi,Surendra,Rao, K. Rama
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p. 669 - 671
(2007/10/03)
-
- Iodine-catalyzed Michael addition of mercaptans to α,β- unsaturated ketones under solvent-free conditions
-
A simple and efficient method for the Michael reaction between various mercaptans and α,β-unsaturated ketones using a catalytic amount of iodine (5 mol %) to generate the 1,4-adduct has been reported. The significant features of the iodine catalyzed Micha
- Chu, Cheng-Ming,Gao, Shijay,Sastry,Yao, Ching-Fa
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p. 4971 - 4974
(2007/10/03)
-
- A simple and green procedure for the conjugate addition of thiols to conjugated alkenes employing polyethylene glycol (PEG) as an efficient recyclable medium
-
Polyethylene glycol (PEG) is found to be an inexpensive, nontoxic, environmentally friendly reaction medium for the conjugate addition of thiols to conjugated alkenes to afford the corresponding adducts in excellent yields under mild and neutral condition
- Kamal, Ahmed,Reddy, D. Rajasekhar,Rajendar
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p. 7951 - 7953
(2007/10/03)
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- H3PW12O40 as a useful recyclable heterogeneous catalyst for the facile and highly efficient Michael addition reaction of thiols to α,β-unsaturated ketones
-
Solid H3PW12O40 is easily used as a heterogeneous, reusable and efficient catalyst (1 mol%) for the selective addition of thiols and dithiols to α,β-unsaturated ketones in MeCN to afford the corresponding Michael adducts i
- Firouzabadi, Habib,Iranpoor, Nasser,Jafari, Abbas Ali
-
p. 299 - 303
(2007/10/03)
-
- Micellar solution of sodium dodecyl sulfate (SDS) catalyzes facile Michael addition of amines and thiols to α,β-unsaturated ketones in water under neutral conditions
-
Sodium dodecyl sulfate (SDS) catalyzes facile Michael additions of amines and thiols to α,β-unsaturated ketones under neutral micellar conditions to afford the corresponding Michael adducts in good to high yields.
- Firouzabadi,Iranpoor,Jafari
-
p. 655 - 661
(2007/10/03)
-
- KF/Al2O3-mediated Michael addition of thiols to electron-deficient olefins
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Potassium fluoride supported on alumina efficiently catalyzes Michael addition of aromatic and aliphatic thiols to a variety of conjugated alkenes such as α,β-unsaturated carbonyl compounds, carboxylic esters, amides, nitriles and chalcones. The Michael adducts are produced in good to excellent yields and relatively in short times. The catalyst can be recycled for subsequent reactions without any appreciable loss of efficiency. Copyright Taylor & Francis, Inc.
- Moghaddam, F. Matloubi,Bardajee, G. Rezanejade,Veranlou, R. Oftadeh Chadorneshine
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p. 2427 - 2433
(2007/10/03)
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- Copper(II) tetrafluoroborate as a novel and highly efficient catalyst for Michael addition of mercaptans to α,β-unsaturated carbonyl compounds
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Copper(II) tetrafluoroborate has been found to be a new and highly efficient catalyst for Michael addition of thiols to α,β-unsaturated carbonyl compounds under solvent-free conditions and in H2O at room temperature. The reactions are very fast
- Garg, Sanjeev K.,Kumar, Raj,Chakraborti, Asit K.
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p. 1721 - 1724
(2007/10/03)
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- Zinc perchlorate hexahydrate catalysed conjugate addition of thiols to α,β-unsaturated ketones
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Zn(II) perchlorate hexahydrate has been found to be a new and efficient catalyst for conjugate addition of thiols to α,β-unsaturated ketones under solvent-free conditions at room temperature. The reaction of aryl, arylalkyl and alkyl thiols with cyclic an
- Garg, Sanjeev K.,Kumar, Raj,Chakraborti, Asit K.
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p. 1370 - 1374
(2007/10/03)
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- Indium(I) iodide-promoted cleavage of dialkyl disulfides and subsequent Michael addition of thiolate anions to conjugated carbonyl compounds
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Indium(I) iodide promotes cleavage of dialkyl disulfides generating thiolate anions which then undergo facile addition to α,β-unsaturated ketones, aldehydes, carboxylic esters and nitriles under neutral conditions producing corresponding β-keto or β-cyano
- Ranu, Brindaban C.,Mandal, Tanmay
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p. 1239 - 1242
(2007/10/03)
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