- Regio- And diastereoselective Pd-catalyzed aminochlorocyclization of allylic carbamates: scope, derivatization, and mechanism
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The regio- and diastereoselective synthesis of oxazolidinonesviaa Pd-catalyzed vicinal C-N/C-Cl bond-forming reaction from internal alkenes of allylic carbamates is reported. The oxazolidinones are obtained in yields of 44 to 95% with high to excellent diastereoselectivities (from 6?:?1 to >20?:?1 dr) from readily available precursors. This process is scalable, and the products are suitable for the synthesis of useful amino alcohols. A detailed theoretical and experimental mechanistic study was carried out to describe that the reaction proceeds through ananti-aminopalladation of the alkene followed by an oxidative C-Pd(ii) cleavage with retention of the carbon stereochemistry to yield the major diastereomer. The role of Cu(ii) in a C-Cl bond-forming mechanism step has also been proposed.
- Ariga, Elaine Miho,Carita Correra, Thiago,Matsushima, Jullyane Emi,McIndoe, J. Scott,Moreira Ribeiro, Francisco Wanderson,Omari, Isaac,Papa Spadafora, Bruna,Rodrigues, Alessandro,Soares, Priscila Machado Arruda,Vinhato, Elisangela,de Oliveira-Silva, Diogo
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supporting information
p. 5595 - 5606
(2021/07/02)
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- Gold-catalyzed partial hydrogenation of activated alkynes mediated by triphenylphosphine
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Gold(I) can exhibit a cooperative effect with triphenylphosphine, accelerating the triphenylphosphine-mediated partial hydrogenation of activated alkynes. In this protocol, 3-arylpropiolates are selectively reduced to the Z -isomer when the aryl ring bears an electron-donor substituent, whereas 3-arylpropynones are reduced to the E-isomers.
- Cocoletzi-Xochitiotzi, Ana Patricia,Hernández-Hernández, Miguel,Medina-Mercado, Ignacio,Jiménez-Martínez, Williams De Jesús,Mastranzo, Virginia Maricela,Porcel, Susana
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supporting information
p. 2379 - 2386
(2020/08/19)
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- Phosphorus-recycling wittig reaction: Design and facile synthesis of a fluorous phosphine and its reusable process in the wittig reaction
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This study shows that phosphorus sources can be recycled using the appropriate fluorous phosphine in the Wittig reaction. The designed fluorous phosphine, which has an ethylene spacer between its phosphorus atom and the perfluoroalkyl group, was synthesized from air-stable phosphine reagents. The synthesized phosphine can be used for the Wittig reaction process to obtain various alkenes in adequate yields and stereoselectivity. The concomitantly formed fluorous phosphine oxide was extracted from the reaction mixture using a fluorous biphasic system. The fluorous phosphine was regenerated by reducing the fluorous phosphine oxide with diisobutylaluminum hydride. Finally, a series of gram scale phosphorus recycling processes were performed, which included the Wittig reaction, separation, reduction, and reuse.
- Yamamoto, Yuki,Kawaguchi, Shin-Ichi,Nishimura, Misaki,Sato, Yuki,Shimada, Yoshihisa,Tabuchi, Akihiro,Nomoto, Akihiro,Ogawa, Akiya
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p. 14684 - 14696
(2020/11/30)
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- Atomically precise palladium nanocluster catalyzed tandem oxidation processes of alcohols and phosphorous ylides: Facile access to α,β-unsaturated esters
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The mesoporous silica nanosphere supported palladium nanocluster was synthesized through a simple impregnation method and well characterized. The as prepared catalyst shows excellent catalytic performance in tandem oxidation process (TOP) of alcohol and phosphorous ylide, which provides an efficient access to α,β-unsaturated esters with high yields utilizes 1 atmosphere of molecular oxygen as sole oxidant. This work represents the first example of atomically precise palladium nanocluster catalyzed tandem oxidation process of alcohol and phosphorous ylide and is expected to open new horizons for nanoclusters in the tandem reactions.
- Gao, Taiping,Du, Jialei,Liu, Wenyan,Ren, Mingxia
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supporting information
(2020/09/17)
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- Phosphine-mediated partial reduction of alkynes to form both (E)- and (Z)-alkenes
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A mild, phosphine-mediated partial reduction of alkynyl carbonyls to the corresponding alkenes was developed. Tuning of the reaction conditions led to either the (E)- or (Z)-diastereomer with high selectivity. A range of alkynyl esters, amides, and ketones were reduced to form alkenes in good to high yields and with excellent functional group tolerance.
- Pierce, Brett M.,Simpson, Brittany F.,Ferguson, Kane H.,Whittaker, Rachel E.
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supporting information
p. 6659 - 6662
(2018/09/29)
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- One-Pot Synthesis of α,β-Unsaturated Esters, Ketones, and Nitriles from Alcohols and Phosphonium Salts
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A general method for the synthesis of α,β-unsaturated esters, ketones, and nitriles is successfully achieved by a one-pot copper-catalyzed oxidation with O 2 in air as oxidant. The solvent mixture of acetonitrile and formamide (1:1) is optimized to ensure the oxidation of alcohols, deprotonation of phosphonium salt, and Wittig reaction occur efficiently in one pot. A broad range of substrates has been explored for this process, including three electron-withdrawing group (CO 2 Et, COPh, CN) functionalized phosphonium salts. They reacted not only with benzylic and heteroaromatic alcohols, but also with aliphatic alcohols, forming the corresponding α,β-unsaturated esters, ketones, and nitriles in moderate to excellent yields.
- Ding, Weijie,Hu, Juan,Jin, Huile,Yu, Xiaochun,Wang, Shun
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p. 107 - 118
(2017/09/28)
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- ATP3 and MTP3: Easily Prepared Stable Perruthenate Salts for Oxidation Applications in Synthesis
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The Ley–Griffith tetra-n-propylammonium perruthenate (TPAP) catalyst has been widely deployed by the synthesis community, mainly for the oxidation of alcohols to aldehydes and ketones, but also for a variety of other synthetic transformations (e.g. diol cleavage, isomerizations, imine formation and heterocyclic synthesis). Such popularity has been forged on broad reaction scope, functional group tolerance, mild conditions, and commercial catalyst supply. However, the mild instability of TPAP creates preparation, storage, and reaction reproducibility issues, due to unpreventable slow decomposition. In search of attributes conducive to catalyst longevity an extensive range of novel perruthenate salts were prepared. Subsequent evaluation unearthed a set of readily synthesized, bench stable, phosphonium perruthenates (ATP3 and MTP3) that mirror the reactivity of TPAP, but avoid storage decomposition issues.
- Moore, Peter W.,Read, Christopher D. G.,Bernhardt, Paul V.,Williams, Craig M.
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supporting information
p. 4556 - 4561
(2018/03/13)
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- Tandem Palladium and Isothiourea Relay Catalysis: Enantioselective Synthesis of α-Amino Acid Derivatives via Allylic Amination and [2,3]-Sigmatropic Rearrangement
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A tandem relay catalytic protocol using both Pd and isothiourea catalysis has been developed for the enantioselective synthesis of α-amino acid derivatives containing two stereogenic centers from readily accessible N,N-disubstituted glycine aryl esters and allylic phosphates. The optimized process uses a bench-stable succinimide-based Pd precatalyst (FurCat) to promote Pd-catalyzed allylic ammonium salt generation from the allylic phosphate and the glycine aryl ester. Subsequent in situ enantioselective [2,3]-sigmatropic rearrangement catalyzed by the isothiourea benzotetramisole forms syn-α-amino acid derivatives with high diastereo- and enantioselectivity. This methodology is most effective using 4-nitrophenylglycine esters and tolerates a variety of substituted cinnamic and styrenyl allylic ethyl phosphates. The use of challenging unsymmetrical N-allyl-N-methylglycine esters is also tolerated under the catalytic relay conditions without compromising stereoselectivity.
- Spoehrle, Stéphanie S. M.,West, Thomas H.,Taylor, James E.,Slawin, Alexandra M. Z.,Smith, Andrew D.
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supporting information
p. 11895 - 11902
(2017/09/07)
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- BF3·OEt2-mediated: Syn -selective Meyer-Schuster rearrangement of phenoxy propargyl alcohols for Z -β-aryl-α,β-unsaturated esters
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Synthesis of Z-β-aryl-α,β-unsaturated esters from readily available 1-aryl-3-phenoxy propargyl alcohols is achieved via a BF3-mediated syn-selective Meyer-Schuster rearrangement under ambient conditions. The reaction mechanism is postulated to involve an electrophilic borylation of an allene intermediate as the key step to kinetically control the stereoselectivity.
- Puri, Surendra,Hari Babu, Madala,Sridhar Reddy, Maddi
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p. 7001 - 7009
(2016/07/30)
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- Iron(IV)-Corrole Catalyzed Stereoselective Olefination of Aldehydes with Ethyl Diazoacetate
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Iron(IV)-corrole complexes were first investigated as catalysts for olefination of aldehydes with ethyl diazoacetate in the presence of triphenylphosphine. Efficient olefination of aromatic aldehydes with high trans-selectivity was observed, showing iron corrole is a new kind of promising catalyst for olefination reaction. Transformation of the phosphazine to ylide by iron(IV) corrole was proved to be the key step in the present system.
- Zou, Huai-Bo,Yang, Hong,Liu, Ze-Yu,Mahmood, Mian H.R.,Mei, Guang-Quan,Liu, Hai-Yang,Chang, Chi-Kwong
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supporting information
p. 2791 - 2795
(2015/06/30)
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- A graphene/hemin hybrid material as an efficient green catalyst for stereoselective olefination of aldehydes
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A hemin/graphene composite, prepared by mixing an aqueous solution of graphene oxide (GO) with hemin and sonicating the suspension for 5 h at room temperature, was investigated for olefination of aldehydes using ethyl diazoacetate in the presence of triphenylphosphine. Efficient olefination of aromatic aldehydes with high (E)-selectivity was obtained, revealing that rGO/hemin is a promising heterogeneous catalyst for the olefination reaction. The as-synthesized catalyst could easily be recovered from the reaction mixture and was subsequently used for several runs without any significantly loss in activity and selectivity.
- Joshi, Chetan,Kumar, Pawan,Behera, Babita,Barras, Alexandre,Szunerits, Sabine,Boukherroub, Rabah,Jain, Suman L.
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p. 100011 - 100017
(2015/12/04)
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- N,N,N′,N′-Tetramethylenediamine dioxide (TMEDAO2) facilitates atom economical/open atmosphere Ley-Griffith (TPAP) tandem oxidation-Wittig reactions
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N,N,N′,N′-Tetramethylethylenediamine dioxide (TMEDAO2) was explored as a more atom economical co-oxidant for the Ley-Griffith oxidation of alcohols to aldehydes. TMEDAO2 was found to selectivity oxidise benzylic and allylic alcohols in comparable yields to that of the standard Ley-Griffith co-oxidant (NMO). Importantly TMEDAO2 facilitated tandem Ley-Griffith-Wittig reactions with stabilised ylides, in good to excellent yields, without the requirement of anhydrous conditions.
- Read, Christopher D. G.,Moore, Peter W.,Williams, Craig M.
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supporting information
p. 4537 - 4540
(2015/09/15)
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- OMS-2 for aerobic, catalytic, one-pot alcohol oxidation-wittig reactions: Efficient access to α,β-unsaturated esters
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Manganese oxide octahedral molecular sieve (OMS) materials with well-defined pores have been extensively studied over two decades due to their intriguing chemical and physical properties. OMS-2, the synthetic cryptomelane form of manganese oxide, was synthesized by a modified reflux method and was found to be highly active for obtaining α,β-unsaturated esters (up to 95 % yield and with high diastereoselectivities) from a variety of benzyl, heteroaryl, allyl and alkyl alcohols via one-pot alcohol oxidation-Wittig reaction. The transformation utilizes air as the stoichiometric oxidant, and the inexpensive catalyst can be recovered and reused. Filter and use again! Porous manganese oxide molecular sieve based catalysts were found to efficiently promote the oxidation of a variety of alcohols to the aldehydes, which reacted insitu with stabilized Wittig reagent, providing almost exclusively E-α,β-unsaturated esters in good to excellent yields. The heterogeneous catalyst used was made from inexpensive starting materials, and the recovered catalyst was found to be reusable with a modest loss in activity.
- Kona, Jagadeswara R.,King'Ondu, Cecil K.,Howell, Amy R.,Suib, Steven L.
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p. 749 - 752
(2014/03/21)
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- PDC-mediated tandem oxidative-wittig olefination
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A convenient tandem oxidative-Wittig olefination of a primary alcohols to α,β-unsaturated compounds using pyridinium dichromate (PDC) is described.
- Dhumaskar, Kashinath L.,Bhat, Chinmay,Tilve, Santosh G.
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supporting information
p. 1501 - 1506
(2014/05/20)
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- Substituent effects of cis-cinnamic acid analogues as plant growh inhibitors
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1-O-cis-Cinnamoyl-β-d-glucopyranose is one of the most potent allelochemicals that has been isolated from Spiraea thunbergii Sieb by Hiradate et al. It derives its strong inhibitory activity from cis-cinnamic acid (cis-CA), which is crucial for phytotoxicity. By preparing and assaying a series of cis-CA analogues, it was previously found that the key features of cis-CA for lettuce root growth inhibition are a phenyl ring, cis-configuration of the alkene moiety, and carboxylic acid. On the basis of a structure-activity relationship study, the substituent effects on the aromatic ring of cis-CA were examined by systematic synthesis and the lettuce root growth inhibition assay of a series of cis-CA analogues having substituents on the aromatic ring. While ortho- and para-substituted analogues exhibited low potency in most cases, meta-substitution was not critical for potency, and analogues having a hydrophobic and sterically small substituent were more likely to be potent. Finally, several cis-CA analogues were found to be more potent root growth inhibitors than cis-CA.
- Nishikawa, Keisuke,Fukuda, Hiroshi,Abe, Masato,Nakanishi, Kazunari,Taniguchi, Tomoya,Nomura, Takashi,Yamaguchi, Chihiro,Hiradate, Syuntaro,Fujii, Yoshiharu,Okuda, Katsuhiro,Shindo, Mitsuru
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p. 132 - 147
(2014/01/06)
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- Diastereoselective liquid assisted grinding: 'Cracking' functional resins to advance chromatography-free synthesis
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As regulations that restrict the use of organic solvents become more stringent, ball milling remains an attractive substitute for traditional organic synthesis. However, the mechanochemistry community does not have a purification pathway to complement the solvent-free, ball milling process. Functional resins have proven to be powerful synthetic tools that simplify purification, but traditional handling of these resins restricts their utility, as hazardous organic solvents are needed to swell the resin. Ball milling the functional resin exposes the functional groups as a function of surface area. This report details the use of ball milling and functional resins to perform an environmentally attractive version of the Wittig reaction.
- Shearouse, William C.,MacK, James
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p. 2771 - 2775,5
(2020/09/14)
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- Update: An efficient synthesis of poly(ethylene glycol)-supported iron(II) porphyrin using a click reaction and its application for the catalytic olefination of aldehydes
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The facile synthesis of polyethylene glycol (PEG)-immobilized iron(II) porphyrin using a copper-catalyzed azide-alkyne [3+2] cycloaddition "click" reaction is reported. The prepared complex 5 (PEG-C 51H39FeN7O) was found to be an efficient catalyst for the selective olefination of aldehydes with ethyl diazoacetate in the presence of triphenylphosphine, and afforded excellent olefin yields with high (E) selectivities. The PEG-supported catalyst 5 was readily recovered by precipitation and filtration, and was recycled through ten runs without significant activity loss. Copyright
- Chinnusamy, Tamilselvi,Rodionov, Valentin,Kuehn, Fritz E.,Reiser, Oliver
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supporting information; experimental part
p. 1827 - 1831
(2012/08/08)
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- Olefination reactions using tetraarylphosphonium (TAP)-supported phosphorus ylides
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Tetraarylphosphonium (TAP)-supported phosphorus ylides were prepared and used in copper-catalyzed olefination reactions with diazo compounds to produce conjugated esters, amides, and phosphonates. The TAP-phosphine oxide can easily be separated from the alkene product, recycled, and reused. Georg Thieme Verlag Stuttgart ? New York.
- Lebel, Helene,Davi, Michael,Roy, Marie-Noelle,Zeghida, Walid,Charette, Andre B.
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experimental part
p. 2275 - 2280
(2011/09/15)
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- An efficient synthesis of poly(ethylene glycol)-supported iron(II) porphyrin using a click reaction and its application for the catalytic olefination of aldehydes
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The first successful synthesis of poly(ethylene glycol) (PEG) immobilized iron(II) porphyrin using a copper-catalyzed azide-alkyne [3+2] cycloaddition is reported. In contrast to the existing methods for the synthesis of PEG-immobilized metalloporphyrins, the click method offers better catalyst loading under comparatively mild reaction conditions. The prepared complex 5 (PEG-C51H39FeN7O) was found to be an efficient catalyst for the selective olefination of aldehydes with ethyl diazoacetate in the presence of triphenylphosphine and afforded excellent olefin yields with high (E) selectivities. The PEG-supported catalyst 5 was readily recovered by precipitation and filtration and was recycled for up to ten runs without significant loss of activity.
- Jain, Suman L.,Joseph, Jomy K.,Kuehn, Fritz E.,Reiser, Oliver
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supporting information; experimental part
p. 230 - 234
(2009/09/06)
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- SYNTHESIS OF CHLORINS AND PHORBINES WITH ENHANCED RED SPECTRAL FEATURES
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The present invention provides compounds of the general Formula DI: along with methods of making such compounds, formulations containing the same, and methods of using the same (e.g., in photodynamic therapy, for the production of solar cells, etc.).
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Page/Page column 126-127; 138
(2008/06/13)
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- One-pot Wittig reactions in aqueous media: A rapid and environmentally benign synthesis of α,β-unsaturated carboxylic esters and nitriles
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One-pot Wittig reactions of ethyl bromoacetate and bromoacetonitrile with aldehydes in the presence of PPh3 and LiOH in water were investigated. Most of the olefination reactions completed within 5-120 min in refluxing water containing 1.2 M LiCl to afford the olefin products in 71-97% yields with 100:0-55:45 ratios of E:Z isomers. Copyright Taylor & Francis Group, LLC.
- Wu, Jinlong,Yue, Congyong
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p. 2939 - 2947
(2007/10/03)
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- Wittig reactions of stabilized phosphorus ylides with aldehydes in water
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The Wittig reactions of three stabilized phosphorus ylides with aldehydes in water were investigated. Most of the olefination reactions completed within 5-60 min in refluxing water in the presence of 1.2 M LiCl to afford the olefin products in 65-98% yields. It was found that the Wittig reactions of stabilized phosphorus ylides with aldehydes in water were faster than those carried out in organic solvents. Copyright Taylor & Francis, Inc.
- Wu, Jinlong,Zhang, Da,Wei, Shaoyong
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p. 1213 - 1222
(2007/10/03)
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- Oxorhenium complexes as aldehyde-olefination catalysts
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Several oxorhenium compounds in the formal oxidation states V and VII are examined as catalysts for the aldehyde-olefination starting from diazo compounds, phosphines, and aldehydes. Of these, [ReMeO2(η 2-alkyne)] complexes provide the simplest catalysts to study, although [ReOCl3(PPh3)2] still remains the most efficient rhenium catalyst for aldehydeolefination described to date. Prior to the reaction with the Re catalysts the phosphine and the diazo compound react to form a phosphazine. No catalytic reaction occurs in cases where no phosphazine formation is observed. The first step of the catalytic cycle involves the formation of a carbene intermediate by the reaction of phosphazine and catalyst under extrusion of phosphine oxide and dinitrogen. In a second step the carbene reacts with aldehyde under olefin formation and catalyst regeneration. Excess of alkyne as well as the presence of ketones slows down the catalytic reaction. The olefination of 4-nitrobenzaldehyde with diazomalonate is possible with these Re catalysts. In contrast, this reaction does not take place either in the classical Wittig fashion from Ph3P=C(CO2Et)2 and aldehyde or by use of all other catalysts for aldehyde olefination reactions reported to date. Catalytic ylide formation from diazo compounds seems therefore not to be the only pathway through which catalytic aldehyde-olefination reactions can proceed.
- Santos, Ana M.,Pedro, Filipe M.,Yogalekar, Ameya A.,Lucas, Isabel S.,Romao, Carlos C.,Kuehn, Fritz E.
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p. 6313 - 6321
(2007/10/03)
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- Solvent-free Wittig olefination with stabilized phosphoranes - Scope and limitations
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Neat mixtures of arene/hetarenecarbaldehydes, alkanals as well as alkenals with alkyl (triphenylphosphoranylidene)acetates react exothermally to furnish the corresponding alkenes. In certain cases, heating has to be provided externally. Reaction times are short and yields are generally very high. Neat mixtures of ketones and alkyl (triphenylphosphoranylidene)acetates react preferentially under microwave irradiation. The better stabilized phosphoranes do not react in the solid state with aldehydes or ketones under conventional heating, but necessitate microwave irradiation, although not all of the phosphoranes have been found to be stable under microwave irradiation at 500 W (2450 MHz).
- Thiemann, Thies,Watanabe, Masataka,Tanaka, Yasuko,Mataka, Shuntaro
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p. 578 - 584
(2007/10/03)
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- Iron(III) and ruthenium(II) porphyrin complex-catalyzed selective olefination of aldehydes with ethyl diazoacetate
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The commercially available Fe(III) and Ru(II) porphyrin complexes Fe(TPP)Cl and Ru(TPP)(CO) are efficient catalysts for selective olefination of a variety of aldehydes with ethyl diazoacetate in the presence of triphenylphosphine. The reactions were carried out under mild conditions in a one-pot fashion with the use of a stoichiometrical amount of EDA, which proceeded with excellent yields and high (E)-selectivity. Air atmosphere, low catalyst loadings, and functional group tolerance were also demonstrated.
- Chen, Ying,Huang, Lingyu,Ranade, Meera A.,Zhang, X. Peter
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p. 3714 - 3717
(2007/10/03)
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- A new and efficient method for the selective olefination of aldehydes with ethyl diazoacetate catalyzed by an iron(II) porphyrin complex
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Olefination of aromatic and aliphatic aldehydes with ethyl diazoacetate was achieved in excellent yields with triphenylphosphine and catalytic amounts of iron(II) meso-tetra(p-tolyl)porphyrin. The reaction conditions are mild and the process is efficient and highly selective (>90%) for the synthesis of the trans-olefin isomer. Results of mechanistic studies are discussed. Copyright
- Mirafzal, Gholam A.,Cheng, Guilong,Woo, L. Keith
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p. 176 - 177
(2007/10/03)
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- Palladium-catalyzed conversion of aldehydes to alkenes in the presence of tri-n-butylphosphine
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Palladium-catalyzed conversion of aldehydes to alkenes in the presence of tri-n-butylphosphine is described.
- Shen, Yanchang,Zhou, Yuefen
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p. 513 - 514
(2007/10/02)
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