1466-20-2Relevant academic research and scientific papers
Catalysis by ionic liquids: Cyclopropyl carbinyl rearrangements catalyzed by [pmim]Br under organic solvent free conditions
Ranu, Brindaban C.,Banerjee, Subhash,Das, Arijit
, p. 881 - 884 (2006)
Aryl substituted cyclopropyl carbinol derivatives undergo stereoselective rearrangements catalyzed by the ionic liquid, 1-methyl-3-pentylimidazolium bromide, under sonication, without any organic solvent, to produce the substituted conjugated all-trans-butadienes.
A new access to 4 h-quinolizines from 2-vinylpyridine and alkynes promoted by rhodium-N-heterocyclic-carbene catalysts
Azpíroz, Ram?n,Di Giuseppe, Andrea,Castarlenas, Ricardo,Pérez-Torrente, Jesús J.,Oro, Luis A.
, p. 3812 - 3816 (2013)
Forging the lock that autolocks! Rh-NHC catalysts promote a new access to 4 H-quinolizine species from 2-vinylpyridine and terminal and internal alkynes through C-H activation and C-C coupling reactions (see figure). N-Bridgehead heterocycle formation is favored for internal- over terminal-substituted butadienylpyridine derivatives in a thermal 6π-electrocyclization process. Copyright
Cascade 8πElectrocyclization/Benzannulation to Access Highly Substituted Phenylpyridines
Du, Luan,Gong, Yiliang,Han, Jingpeng,Li, Baosheng,Li, You,Luo, Han,Tian, Yi,Xin, Xiaolan
supporting information, p. 7966 - 7971 (2021/10/25)
A cascade 8πelectrocyclization/benzannulation reaction was developed to obtain the synthetically important highly substituted phenyl-pyridines. This method shows great potential in the rapid and inexpensive application of the scalable and operationally simple production of accessible substrates. On the basis of the resulting phenyl-pyridine products, a new Ru catalyst and bidentate ligand were designed and prepared, further demonstrating its high practicability.
Direct Wittig Olefination of Alcohols
Li, Qiang-Qiang,Shah, Zaher,Qu, Jian-Ping,Kang, Yan-Biao
, p. 296 - 302 (2018/02/19)
A base-promoted transition metal-free approach to substituted alkenes using alcohols under aerobic conditions using air as the inexpensive and clean oxidant is described. Aldehydes are relatively difficult to handle compared to corresponding alcohols due to their volatility and penchant to polymerize and autoxidize. Wittig ylides are easily oxidized to aldehydes and consequently form homo-olefination products. By the strategy of simultaneously in situ generation of ylides and aldehydes, for the first time, alcohols are directly transferred to olefins with no need of prepreparation of either aldehydes or ylides. Thus, the di/monocontrollable olefination of diols is accomplished. This synthetically practical method has been applied in the gram-scale synthesis of pharmaceuticals, such as DMU-212 and resveratrol from alcohols.
A highly tunable stereoselective olefination of semistabilized triphenylphosphonium ylides with N -Sulfonyl imines
Dong, De-Jun,Li, Hai-Hua,Tian, Shi-Kai
supporting information; experimental part, p. 5018 - 5020 (2010/06/13)
The Wittig reaction involving direct olefination of triphenylphosphonium ylides (Ph3PCHR) with aldehydes is arguably the most often used method for alkene synthesis, but in general it yields mixtures of Z- and E-alkenes for semistabilized triphenylphosphonium ylides (R = aryl or vinyl). We have developed a simple and efficient protocol to improve the stereoselectivity significantly by replacing the aldehydes used in the Wittig reaction with N-sulfonyl imines, which possess distinct electronic and steric properties relative to aldehydes. A broad range of aromatic, α,β-unsaturated, and aliphatic imines bearing appropriate N-sulfonyl groups smoothly undergo olefination reaction with various benzylidenetriphenylphosphoranes or allylidenetriphenylphosphoranes under mild reaction conditions to afford an array of both Z- and E-isomers of conjugated alkenes in good to excellent yields and with greater than 99:1 stereoselectivity. Moreover, this tunable protocol has been successfully applied to the highly stereoselective synthesis of two anticancer agents, DMU-212 and its Z-isomer.
Palladium-tetraphosphine complex catalysed heck reaction of vinyl bromides with alkenes: A powerful access to conjugated dienes
Lemhadri, Mhamed,Battace, Ahmed,Berthiol, Florian,Zair, Touriya,Doucet, Henri,Santelli, Maurice
, p. 1142 - 1152 (2008/12/22)
A wide variety of 1,3-dienes have been prepared by the Heck vinylation of vinyl bromides using [Pd(η3-C3H5)Cl] 2/cis,cis,cis-1,2,3,4-tetrakis[(diphenylphosphino)methyl] cyclopentane (Tedicyp) as the catalyst precursor. Both α- and β-substituted vinyl bromides undergo the Heck reaction with functionalised alkenes such as acrylates, enones, styrenes or a vinyl sulfone, and also with nonfunctionalised alkenes such as dec-1-ene, leading stereoselectively, in most cases, to the corresponding E- or E,E-1,3-dienes in good yields. Furthermore, this catalyst can be used at low loading for several reactions. Georg Thieme Verlag Stuttgart.
Utilities of olefin derivatives
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Page/Page column 23; 32, (2008/06/13)
Compounds having an activity to enhance the expression of apoAI are provided. Compounds of formula (I): in which Ar1 and Ar2 are independently a phenyl, naphthyl, or monocyclic or bicyclic aromatic heterocyclic group, which may be optionally substituted; —X— is —N═CZ2-, —CY2═CZ2-, —CY2Y3—CHZ2-, —S—, —O—, or the like; Y1, Y2, Y3, Z1 and Z2 are independently a hydrogen, a halogen, a lower alkyl, a phenyl, or the like; Z1 and Z2 may be independently a linker group that may combine with Ar2 and Ar1 to form a condensed ring; m is 0 or 1, and n is 0 to 2; a prodrug thereof, a pharmaceutically acceptable salt or solvate of them; are disclosed.
Heck reaction of vinyl bromides with alkenes in the presence of a tetraphosphine/palladium catalyst
Berthiol, Florian,Doucet, Henri,Santelli, Maurice
, p. 841 - 844 (2007/10/03)
Through the use of [PdCl(C3H5)]2- cis,cis,cis-1,2,3,4-tetrakis(diphenylphosphinomethyl)cyclopentane as a catalyst, a range of vinyl bromides undergo Heck reaction with a wide variety of alkenes leading selectively to the corresponding 1,3-dienes in good yields. Furthermore, it can be used at low loading even for reactions of sterically hindered vinyl bromides.
Photoisomerization mechanisms and photoselectivity of the stereoisomers of 1-(pyrid-n-yl),4-phenylbuta-1,3-diene
Bartocci,Galiazzo,Latterini,Marri,Mazzucato,Spalletti
, p. 2911 - 2916 (2007/10/03)
The positional isomers of 1-(pyrid-n-yl),4-phenylbuta-1,3-diene (n = 2, 3 and 4) have been synthesized and characterized by spectrometric techniques. All the four expected stereoisomers (EE, EZ, ZE and ZZ) were prepared for n = 2 while only three and two geometrical isomers were obtained for the positional isomers with n = 3 and 4, respectively. Their excited state properties were investigated by stationary and pulsed fluorimetric techniques and by laser flash photolysis. This paper describes the photochemical behaviour under direct and triplet sensitized excitation. The selective formation of photoproducts and the role of diabatic/adiabatic mechanisms are reported and compared with the results on the direct photoisomerization of the EE and ZE isomers in the singlet manifold described in a previous paper (G. Bartocci, G. Galiazzo, U. Mazzucato and A. Spalletti, Phys. Chem. Chem. Phys., 2001, 3, 379-386).
Photophysics and photochemistry of the EE and ZE isomers of 1-(n-pyridyl)-4-phenyl-1,3-butadiene (n = 2, 3 and 4)
Bartocci,Galiazzo,Mazzucato,Spalletti
, p. 379 - 386 (2007/10/03)
The positional isomers of 1-(n-pyridyl)-4-phenyl-1,3-butadiene (n = 2, 3 and 4) have been synthesized in the EE and ZE geometries by common routes and characterized by spectrometric techniques. Their excited state properties were investigated by stationary and pulsed fluorimetric techniques and by laser flash photolysis. This paper reports the spectral, photophysical and photochemical behaviour of the EE and ZE isomers in a non-polar solvent. The photoisomerization proceeds through singlet, diabatic and/or adiabatic mechanisms with generally low quantum yield, owing to the role of internal conversion (markedly more important for n = 2). The role of intramolecular hydrogen bonds on the excited state properties of the ZE isomer of the 2-pyridyl derivative is particularly described.
