- 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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- 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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- Synthesis of olefins via a Wittig reaction mediated by triphenylarsine
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An arsine-mediated Wittig reaction for the synthesis of olefins is described. After heating triphenylarsine in the presence of an activated alkyl bromide for 30?min, the resulting arsonium salt condensed with aldehydes in as little as 5?min at room temperature, yielding the olefins in high yields. Aromatic, heteroaromatic, and alkyl aldehydes were all suitable substrates for this process.
- Li, Lun,Stimac, Jared C.,Geary, Laina M.
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supporting information
p. 1379 - 1381
(2017/03/17)
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- Copper-catalyzed retro-aldol reaction of β-hydroxy ketones or nitriles with aldehydes: Chemo- and stereoselective access to (E)-enones and (E)-acrylonitriles
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A copper-catalyzed transfer aldol type reaction of β-hydroxy ketones or nitriles with aldehydes is reported, which enables chemo- and stereoselective access to (E)-α,β-unsaturated ketones and (E)-acrylonitriles. A key step of the in situ copper(i)-promoted retro-aldol reaction of β-hydroxy ketones or nitriles is proposed to generate a reactive Cu(i) enolate or cyanomethyl intermediate, which undergoes ensuing aldol condensation with aldehydes to deliver the products. This reaction uses 1.2 mol% Cu(IPr)Cl (IPr denotes 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) as the catalyst in the presence of 6.0 mol% NaOtBu cocatalyst at room temperature or 70 °C. A range of aryl and heteroaryl aldehydes as well as acrylaldehydes are compatible with many useful functional groups being tolerated. Under the mild and weakly basic conditions, competitive Cannizzaro-type reaction of benzaldehydes and side reactions of base-sensitive functional groups can be effectively suppressed, which show synthetic advantages of this reaction compared to classic aldol reactions. The synthetic potential of this reaction is further demonstrated by the one-step synthesis of biologically active quinolines and 1,8-naphthyridine in excellent yields (up to 91%). Finally, a full catalytic cycle for this reaction has been constructed using DFT computational studies in the context of a retro-aldol/aldol two-stage mechanism. A rather flat reaction energy profile is found indicating that both stages are kinetically facile, which is consistent with the mild reaction conditions.
- Zhang, Song-Lin,Deng, Zhu-Qin
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p. 7282 - 7294
(2016/08/05)
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- Cu-catalyzed debrominative cyanation of gem-dibromoolefins: A facile access to α,β-unsaturated nitriles
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An efficient catalytic route for the synthesis of α,β-unsaturated nitriles from easily accessible gem-dibromoolefins has been developed. The method utilized inexpensive reagents such as Cu2O as a catalyst, l-proline as a ligand and NaCN as a cyanide source to afford α,β-unsaturated nitriles in high yields (62-86%). A deuterium exchange study has shown that one of the bromide atoms of gem-dibromoolefins exchanges with cyanide while the other with a deuterium atom.
- Ahuja, Brij Bhushan,Sudalai, Arumugam
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p. 5918 - 5923
(2015/06/02)
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- Wittig Olefination Using Phosphonium Tetraphenylborate in the Absence of Additional Base
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The thermal decomposition of (substituted methyl)triphenylphosphonium tetraphenylborates, which can also be generated in situ from the corresponding phosphonium halide and NaBPh4, with an aldehyde affords olefins in 22-100% yields. This Wittig olefination does not need use additional base to form phosphorus ylide, and is highly tolerant of benzoic acid.
- Huang, Wenhua,Zhao, Shuang-Hong,Dong, Guang-Ping
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supporting information
p. 1802 - 1810
(2015/10/29)
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- Highly Z-selective synthesis of a,b-unsaturated nitriles using the Horner-Wadsworth-Emmons reaction
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A new HWE reagent, (o-tBuC6H4O)2P(O)CH2CN (2e), reacts with various types of aldehydes to give Z-a,bunsaturated nitriles with 86% to >99% Z-selectivity. Especially, the reaction of 2e with bulkier aldehydes, both aromatic and aliphatic, gave the Z-olefins with extremely high selectivity. The combination of t-BuOK and 18-crown-6 (1 equiv) is the base of choice for aromatic aldehydes and t-BuOK is generally the base of choice for aliphatic aldehydes.
- Ando, Kaori,Okumura, Miho,Nagaya, Shigeo
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p. 2026 - 2028
(2013/04/23)
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- A facile, one-pot synthesis of β-substituted (Z)-acrylonitriles utilizing an α-diaminoboryl carbanion
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A simple three-step single-pot procedure for Z-stereoselective synthesis of β-monosubstituted acrylonitriles has been established. The reaction involves olefination of aldehydes with an in situ generated α-diaminoboryl carbanion species. Various aromatic and aliphatic aldehydes were smoothly converted into the corresponding (Z)-olefin products (up to 96:4 ratio) in good yields (80-98%).
- Tomioka, Takashi,Takahashi, Yusuke,Vaughan, Trey G.,Yanase, Takayoshi
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supporting information; experimental part
p. 2171 - 2173
(2010/07/08)
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- Direct oxidative coupling of benzenes with acrylonitriles to cinnamonitriles catalyzed by Pd(OAc)2/HPMoV/O2 system
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A facile direct synthesis of cinnamonitriles from acrylonitriles and benzenes is successfully achieved by using Pd(OAc)2/HPMoV/O 2 catalyst system via the direct C-H bond activation of benzenes using molecular oxygen as a terminal oxidant.
- Obora, Yasushi,Okabe, Yoshihisa,Ishii, Yasutaka
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supporting information; experimental part
p. 4071 - 4073
(2010/11/04)
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- Indium(I) bromide-mediated coupling of dibromoacetonitrile with aldehydes followed by Boord elimination of bromine and oxygen of β-bromo alkoxides for preparation of 3-organyl-2-alkenenitriles
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The organoindium compound derived from indium monobromide and dibromoacetonitrile reacts with carbonyl compounds to afford the corresponding 2-bromo-2-cyano-indium(III) alkoxide. The action of a second equivalent of indium monobromide onto the alkoxides derived from aldehydes promotes the Boord elimination of the β-related oxygen and bromine atoms leading to 2-alkenenitriles.
- Peppe, Clovis,de Azevedo Mello, Paola,das Chagas, Rafael Pav?o
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p. 2335 - 2339
(2007/10/03)
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- Phosphine-free palladium catalyzed Mizoroki-Heck reaction using hydrazone as a ligand
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Glyoxal bishydrazones 1 and pyridyl-hydrazone 2b were prepared and examined as a ligand for the Mizoroki-Heck cross-coupling reaction of aryl halides and olefin. We found that PdCl2(MeCN)2/hydrazone ligand 1e was a phosphine-free efficient catalyst system for a variety of substrates to produce the Mizoroki-Heck coupling products in good yields.
- Mino, Takashi,Shirae, Yoshiaki,Sasai, Yousuke,Sakamoto, Masami,Fujita, Tsutomu
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p. 6834 - 6839
(2007/10/03)
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- Synthetic studies related to diketopyrrolopyrrole (DPP) pigments. Part 1: The search for alkenyl-DPPs. Unsaturated nitriles in standard DPP syntheses: A novel cyclopenta[c]pyrrolone chromophore
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Reactions of the anion of ethyl 4,5-dihydro-5-oxo-2-phenylpyrrole-3-carboxylate with the Diels-Alder adducts of acrylonitrile and various dienes rarely yield the expected DPP derivatives. The reaction with cyclohex-3-enecarbonitrile provides a noteworthy exception: thermolysis of the resulting cyclohexenyl-DPP gives butadiene and impure 3-ethenyl-6-phenyl-DPP, the latter being thermally unstable. Michael additions predominate when the above anion reacts with α,β-unsaturated nitriles: acrylonitrile and methacrylonitrile give 4,4-bis(cyanoethyl) and 4,4-bis(2-cyanopropyl) derivatives, and cinnamonitrile, substituted cinnamonitriles and 3-(2-thienyl)acrylonitrile give deep red 3-aryl-5-cyano-4-hydroxy-2H-cyclopenta[c]pyrrol-1-ones. These ambident nucleophiles may undergo N- and either O- or C-alkylation according to the alkylating agent used.
- Morton, Colin J.H,Gilmour, Ryan,Smith, David M,Lightfoot, Philip,Slawin, Alexandra M.Z,MacLean, Elizabeth J
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p. 5547 - 5565
(2007/10/03)
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- A polymer-supported β-ketoesterate complex of palladium as an efficient, phosphane-free, air-stable, recyclable catalyst for the heck reaction
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The coupling between aryl iodides and bromides with olefins (Heck reaction) has been studied with a polymer-supported palladium catalyst in the presence of sodium or potassium acetate. The reactions can be performed in air without any activating phosphorus ligands and with non dried solvents. Under suitable conditions the catalyst, which exhibits high activity and selectivity, is recyclable several times with negligible leaching of metal. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
- Dell'Anna, Maria M.,Mastrorilli, Piero,Muscio, Francesco,Nobile, Cosimo F.,Suranna, Gian P.
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p. 1094 - 1099
(2007/10/03)
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- A New Version of the Peterson Olefination Using Bis(trimethylsilyl)methyl Derivatives and Fluoride Ion as Catalyst
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Reaction between a variety of bis(trimethylsilyl)methyl derivatives and carbonyl compounds under fluoride ion as catalyst is described.The reaction works especially well with nonenolizable carbonyl compounds to give the expected alkenes in high yields and, in some cases, with high stereoselectivity.Application of this methodology to an intramolecular alkenation providing a tricyclic benzocarbacephem ring system is also described.
- Palomo, Claudio,Aizpurua, Jesus M.,Garcia, Jesus M.,Ganboa, Inaki,Cossio, F. P.,et al.
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p. 2498 - 2503
(2007/10/02)
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- A Convenient Synthesis of α,β-Unsaturated Nitriles
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α,β-Unsaturated nitriles were synthesized by the reaction of aldehydes with bromoacetonitrile promoted by tri-n-butylphosphine and zinc.
- Zheng, Jianhua,Yu, Yang,Shen, Yanchang
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p. 3277 - 3282
(2007/10/02)
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- A stereoselective synthesis of cis-alkenenitriles through reformatsky-Peterson reaction
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A new procedure for the preparation of alkenenitriles from trimethylsilylchloroacetonitrile and carbonyl compounds promoted by zinc is described.
- Palomo, Claudio,Aizpurua, Jesus M.,Aurrekoetxea, Natalia
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p. 2209 - 2210
(2007/10/02)
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- Thermolysis of Polyazapentadienes. Part 7. An Unambiguous Route to 7-Substituted Quinolines from Cinnamaldehyde Derivatives
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Flash vacuum pyrolysis of the cinnamaldehyde phenylhydrazone derivatives (4) - (6) or O-alkyl oxime derivatives (7) - (12) at 600 -650 deg C and 10-2 - 10-3 Torr leads to approximately equal quantities of cinnamonitriles and quinolines.Use of a p-substituted cinnamaldehyde derivatives gives the appropriate 7-substituted quinoline in high isomeric purity; the reactions take place via conjugated iminyl radicals.
- Hickson, Clare L.,McNab, Hamish
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p. 1569 - 1572
(2007/10/02)
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- Transmiision of substituent effects through extended systems II. Substituted cis and trans cinnamonitriles
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Infrared data and 13C chemical shifts are reported for a series of p-substituted cis and m-substituted trans cinnamonitriles.The i.r. values include intensities for the benzene, ethylene and cyanide vibrations which allow an estimation of resonance effect
- Butt, G.,Topsom, R. D.
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p. 301 - 306
(2007/10/02)
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