100-13-0Relevant articles and documents
Elimination in sulfobetaine micelles: Effects of head group bulk
Brinchi, Lucia,Germani, Raimondo,Savelli, Gianfranco,Bunton, Clifford A.
, p. 890 - 894 (1999)
Zwitterionic micelles of tetradecyldimethylammoniopropanesulfonate and tetradecyldibutylammoniopropanesulfonate, SB3-14 and SBBu3-14, respectively, accelerate the E2 reaction of OH- with 4-nitrophenethyl bromide (1b), but the reaction of phenet
Efficient Stille cross-coupling reaction catalyzed by the Pd(OAc) 2/Dabco catalytic system
Li, Jin-Heng,Liang, Yun,Wang, De-Ping,Liu, Wen-Jie,Xie, Ye-Xiang,Yin, Du-Lin
, p. 2832 - 2834 (2005)
(Chemical Equation Presented) An efficient Pd(OAc)2/Dabco- catalyzed Stille cross-coupling reaction procedure has been developed. In the presence of Pd(OAc)2 and Dabco (triethylenediamine), various aryl halides including aryl iodides, aryl bromides, and activated aryl chlorides were coupled efficiently with organotin compounds to afford the corresponding biaryls, alkene, and alkynes in good to excellent yields. Furthermore, high TONs [turnover numbers, up to 980 000 TONs for the coupling reaction of 1-bromo-4-nitrobenzene and furan-2-yltributyltin] for the Stille cross-coupling reaction were observed.
EFFECT OF CYCLIC ACETAL-TYPE CATIONIC SURFACTANTS ON THE BASIC DEHYDROBROMINATION REACTION
Wilk, Kazimiera A.,Bieniecki, Albert,Matuszewska, Barbara
, p. 646 - 651 (1994)
The reaction of 2-(p-nitrophenyl)ethyl bromide with hydroxide ion was studied at 50 and 25 deg C in the presence of cationic chemodegradable surfactants, i.e. trimethylammonium bromides Ia-c (alkyl: a = n-C9H19, b = n-C11H23, c = n-C13H27).The kinetic data were interpreted with the pseudo-phase ion-exchange (PIE) formalzm at both temperatures.The results indicate that the major source of rate enhancement is the increased reactant concentration in the small micellar reaction volume.The surfactant stability in micellar conditions was probed by means of a hydrolysis reaction of the surfactant 1,3-dioxolane ring.The kinetics of acid hydrolysis of Ia-c micelles, as a result of specific hydronium ion concentration, is one order of magnitude smaller than that of unaggregated systems.
P(CH3NCH2CH2)3N: A Nonionic Superbase for Efficient Dehydrohalogenation
Arumugam, Subramaniam,Verkade, John G.
, p. 4827 - 4828 (1997)
The commercially available nonionic Superbase P(CH3NH2CH2)3N (1) is far superior to DBU for the conversion of primary and secondary alkyl halides to alkenes. A reason for the efficacy of acetonitrile as a solvent for the halides requiring extended reaction times is presented.
Low pressure vinylation of aryl and vinyl halides via Heck-Mizoroki reactions using ethylene
Smith, Craig R.,RajanBabu
, p. 1102 - 1110 (2010)
Aryl bromides and iodides in the presence of catalytic amounts of a palladacycle derived from acetophenone oxime and 2 equiv of potassium acetate react with ethylene under ambient pressure (15-30 psi) to give the corresponding vinylarenes. The reactions work with both electron-deficient and electron-rich aryl compounds and tolerate wide variety of common functional groups. Vinyl bromides lead to 1,3-dienes in moderate yields.
Metal-free and base-free decarboxylation of substituted cinnamic acids in a deep eutectic solvent
Chen, Chen,Jian, Yuqing,Lei, Yuxin,Li, Bin,Peng, Caiyun,Sheng, Wen-Bing,Sumera, Yasmin,Wang, Wei,Zhang, Ming
, p. 558 - 563 (2020)
A metal-free and base-free strategy was developed in DES to synthesize styrenes for the first time by decarboxylation of cinnamic acid derivatives, which provided a renewable and cost efficiently protocol to access various styrenes including those with functional groups such as 4-vinylphenol and 1-chloro-4-vinylbenzene.
Electrostatic Stabilization of the Transition State in Proton Transfer from Carbon
Thibblin, Alf
, p. 183 - 186 (1984)
The base-promoted reactions of 2-(p-nitrophenyl)ethyl chloride (1), 9-(chloromethyl)fluorene (2), 1-(2-chloro-2-propyl)indene (3), and 1-(2-acetoxy-2-propyl)indene (4) have been studied in 28 molpercent Me2SO4-H2O.They all exhibit rate-limiting proton transfer.Quinuclidine (Q) was found to be a more effective general base "catalyst" than hexafluoro-2-propanol anion (P-) in these reactions.Thus, after correction for the small difference in thermodinamic basicity, the following rate constant ratios kQ/kp- were obtained: 1.2, 4.4, 3.6, and 16, respectively.The small ratio for 1 indicates that partial desolvation of P- is responsible fo not more than a minor part of the rate differences between Q and P- in these reactions.It is concluded that the reactions of 2, 3, and 4 are accelerated by electrostatic interaction between the developing positive charge on the tertiary amine and the partial negative charge on the carbon atom in the transition state.This favorable electrostatic interaction seems to be considerably larger in methanol.
Pd-grafted periodic mesoporous organosilica: An efficient heterogeneous catalyst for Hiyama and Sonogashira couplings, and cyanation reactions
Modak, Arindam,Mondal, John,Bhaumik, Asim
, p. 2840 - 2855 (2012)
The high surface area of 2D-hexagonal periodic mesoporous organosilica (PMO) containing a phloroglucinol-diimine moiety inside the pore wall has been utilized for grafting Pd(ii) at the surface of the mesopores. This Pd-containing PMO material (Pd-LHMS-3) shows excellent catalytic activity in fluoride-free Hiyama cross-coupling reactions in water at alkaline pH conditions. Sonogashira cross-couplings between terminal alkynes and aryl halides take place in the presence of water and hexamine as base in the absence of any Cu co-catalyst. Cyanation of aryl halides is equally promoted with K4[Fe(CN) 6] as the cyanide source (in the absence of poisonous KCN, NaCN or Zn(CN)2) over Pd-LHMS-3. Excellent yield of the products, reusability and the facile work-up could make this Pd-grafted PMO material a unique catalyst for the synthesis of substituted benzonitriles, unsymmetrical biphenyls and di-substituted alkynes under environmentally benign reaction conditions. Further good yield of products and no evidence of leached Pd from the catalyst surface during the reaction and its smooth recovery confirm the true heterogeneity in these catalytic reactions.
Synthesis of Stilbene-Quinone Hybrids through Heck Reactions in PEG-400
Demidoff, Felipe C.,De Souza, Fabrícia P.,Netto, Chaquip D.
, p. 5217 - 5223 (2017)
Styrenes were coupled with 3-iodolawsone in PEG-400 at 90 °C, leading stereoselectively to (E)-stilbene-quinone hybrids through Heck reactions. The best reaction conditions were found to be the use of NaOH (3 equiv) and 10 mol% of palladium acetate at 90 °C for 15 minutes. The chemical yields of the Heck reactions using styrenes with electron-withdrawing groups (65-98%) were greater than styrenes bearing electron-donating groups (7-32%) on the aromatic ring. In particular, the chemical yields of Heck reactions involving nitrostyrenes were the best ones observed.
Phosphane-free hiyama cross-coupling of aryl and heteroaryl halides catalyzed by palladium nanoparticles in ionic liquids
Premi, Chanchal,Jain, Nidhi
, p. 5493 - 5499 (2013)
Palladium nanoparticles (NPs) 2-5 nm in size and preformed by thermal reduction in nitrile-functionalized 3-(3-cyanopropyl)-1-methyl-1H-imidazol-3-ium hexafluorophosphate {[CN-bmim]PF6} act as an in situ catalyst for carbon-carbon bond-forming reactions of aromatic and heterocyclic halides with aryl- and vinyltrimethoxysilanes. A variety of biphenyl derivatives, substituted styrenes, and aromatic heterocycles were obtained in 76 to 98 % yield. We demonstrate for the first time the use of 1-butyl-3-methylimidazolium fluoride as an activator of the organosilanes with easy handling, storage, and workup in comparison to conventional fluorine sources such as tetrabutylammonium fluoride, which is indispensable for Hiyama coupling. Pd NPs immobilized in [CN-bmim]PF6 gave high yields of the cross-coupled products at a low catalyst loading of only 4 mol-%, and the catalyst could be reused and recycled up to four times with only a slight loss in catalytic activity. Phosphane-free Hiyama coupling of aryl- and vinyltrimethoxysilanes with aromatic and heterocyclic halides catalyzed by palladium nanoparticles in nitrile-functionalized ionic liquids to yield a range of biphenyl derivatives, substituted styrenes, and aromatic heterocycles is reported. The catalytic system can be recycled at least four times with only a slight loss in catalytic activity. Copyright
