- Direct organocatalytic oxo-metathesis, a trans-selective carbocation-catalyzed olefination of aldehydes
-
A direct organocatalytic carbonyl/olefin oxo-metathesis has been developed. The reaction is catalyzed by trityl tetrafluoroborate (TrBF4) and utilizes unactivated alkenes for the olefination of aromatic aldehydes to give trans β-alkylstyrenes in yields of 44-85% with only acetone as the byproduct. The pronounced Lewis acidity of the carbocation results in unusual reactivity that is proposed to catalyze a stepwise [2+2] cycloaddition to give an oxetane intermediate. Fragmentation of the latter in a formal retro [2+2] reaction gives the oxo-metathesis product.
- Naidu, Veluru Ramesh,Bah, Juho,Franzén, Johan
-
-
Read Online
- Convenient preparation of trans-arylalkenes via palladium(II)-catalyzed isomerization of cis-arylalkenes
-
A convenient method for the isomerization of cisarylalkenes to their trans isomers using a palladium(II) catalyst is described. The reaction conditions are mild and general across a range of arylalkenes. The synthesis of a trans-resveratrol derivative from a mixture of alkene isomers was also completed.
- Yu, Jinquan,Gaunt, Matthew J.,Spencer, Jonathan B.
-
-
Read Online
- Method for synthesizing alkyl olefin through coupling of double-bond carbon-hydrogen bond and saturated carbon-hydrogen bond
-
The invention discloses a method for synthesizing alkyl olefin through coupling of a double-bond carbon-hydrogen bond and a saturated carbon-hydrogen bond. According to to the method, one-pot reactionis implemented on olefin and sulfoxide in the presence of ferric salt and hydrogen peroxide to generate alkyl olefin; in the method, sulfoxide is simultaneously used as a hydrocarbylation reagent anda solvent of olefin, and a reaction product is alkyl olefin from sulfoxide alkyl coupled with olefin carbon atoms, so that an olefin carbon chain is increased; the reaction conditions are mild, the selectivity is good, the yield is high, and industrial production is facilitated.
- -
-
Paragraph 0060-0064; 0086
(2021/02/10)
-
- Method for synthesizing 1, 2-disubstituted olefin through reaction of terminal group olefin and sulfoxide
-
The invention discloses a method for synthesizing 1, 2-disubstituted olefin by reaction of terminal olefin and sulfoxide. According to the method, terminal olefin with sulfoxide make reaction in one pot in the presence of ferric salt and hydrogen peroxide to generate the 1, 2-disubstituted olefin. sulfoxide is simultaneously used as a hydrocarbylation reagent and a solvent of olefin, and a reaction product is 1, 2-disubstituted olefin of which a terminal carbon atom in terminal olefin is coupled with a sulfoxide alkyl group, so that an olefin carbon chain is increased; the reaction conditionsare mild, the selectivity is high, the yield is high, and industrial production is facilitated.
- -
-
Paragraph 0053-0054; 0057-0062; 0073
(2021/02/10)
-
- Iron Catalyzed Double Bond Isomerization: Evidence for an FeI/FeIII Catalytic Cycle
-
Iron-catalyzed isomerization of alkenes is reported using an iron(II) β-diketiminate pre-catalyst. The reaction proceeds with a catalytic amount of a hydride source, such as pinacol borane (HBpin) or ammonia borane (H3N?BH3). Reactivity with both allyl arenes and aliphatic alkenes has been studied. The catalytic mechanism was investigated by a variety of means, including deuteration studies, Density Functional Theory (DFT) and Electron Paramagnetic Resonance (EPR) spectroscopy. The data obtained support a pre-catalyst activation step that gives access to an η2-coordinated alkene FeI complex, followed by oxidative addition of the alkene to give an FeIII intermediate, which then undergoes reductive elimination to allow release of the isomerization product.
- Woof, Callum R.,Durand, Derek J.,Fey, Natalie,Richards, Emma,Webster, Ruth L.
-
supporting information
p. 5972 - 5977
(2021/03/17)
-
- Cobalt-Catalyzed Z to e Isomerization of Alkenes: An Approach to (E)-β-Substituted Styrenes
-
An efficient cobalt-catalyzed Z to E isomerization of β-substituted styrenes using the amido-diphosphine ligand was developed, delivering the (E)-isomers with good functional tolerance and high stereoselectivity. The reaction could be scaled up to gram-scale with a catalyst loading of 0.1 mol %, using a mixture of (Z)- and (E)-alkene as the starting material. Preliminary mechanistic studies indicated that cobalt(I)-hydride and a benzylic-cobalt species were probably involved in the reaction, as supported by experiments and DFT calculations.
- Liu, Hongmei,Xu, Man,Cai, Cheng,Chen, Jianhui,Gu, Yugui,Xia, Yuanzhi
-
supporting information
p. 1193 - 1198
(2020/02/04)
-
- Superelectrophilic Fe(III)-Ion Pairs as Stronger Lewis Acid Catalysts for (E)-Selective Intermolecular Carbonyl-Olefin Metathesis
-
An intermolecular carbonyl-olefin metathesis reaction is described that relies on superelectrophilic Fe(III)-based ion pairs as stronger Lewis acid catalysts. This new catalytic system enables selective access to (E)-olefins as carbonyl-olefin metathesis products. Mechanistic investigations suggest the regioselective formation and stereospecific fragmentation of intermediate oxetanes to be the origin of this selectivity. The optimized conditions are general for a variety of aryl aldehydes and trisubstituted olefins and are demonstrated for 28 examples in up to 64% overall yield.
- Albright, Haley,Schindler, Corinna S.,Vonesh, Hannah L.
-
supporting information
p. 3155 - 3160
(2020/04/21)
-
- Process for isomerizing and converting (Z)-olefins to (E)-olefins
-
The invention belongs to the technical field of metal catalytic synthesis, and discloses a method for isomerizing and converting (Z)-olefins into (E)-olefins. The (E)-olefins are prepared through a reaction at -30-80 DEG C for 0.5-48 h by using a combination of CoX2 and a PNP or PAO ligand as a catalyst in the presence of an activating reagent; and a molar ratio of the (Z)-olefins to the CoX2 to the PNP or PAO ligand to the activating reagent is 1:(0.00001-0.10):(0.00001-0.10):(0.00003-0.30). The catalyst used in the invention is the combination of the cheap metal cobalt salt and the simple and easily available ligand, no other toxic transition metal (such as ruthenium, rhodium and palladium) salt is added in the reaction, and the method also has the advantages of cheap and easily available raw material, good functional group tolerance, mild reaction conditions, simplicity in operation, and e atom economy of 100%.
- -
-
Paragraph 0048-0050; 0066-0068; 0084-0086
(2020/03/25)
-
- PICOLINAMIDES AS FUNGICIDES
-
This disclosure relates to picolinamides of Formula I and their use as fungicides.
- -
-
Paragraph 0068-0069
(2018/03/25)
-
- PICOLINAMIDES AS FUNGICIDES
-
This disclosure relates to picolinamides of Formula I and their use as fungicides.
- -
-
Paragraph 0081; 0082
(2018/07/29)
-
- Nitrogen-Doped Carbon-Encapsulated Nickel/Cobalt Nanoparticle Catalysts for Olefin Migration in Allylarenes
-
Olefin migration in allylarenes is typically performed with precious-metal-based homogeneous catalysts. In contrast, very limited progress has been made with the use of cheap, Earth-abundant base metals as heterogeneous catalysts for these transformations—in spite of the obvious economic and environmental advantages. Herein, we report on the use of an easily prepared heterogeneous catalyst material for the migration of olefins, in particular, for allylarenes. The catalyst material consists of nickel/cobalt alloy nanoparticles encapsulated in nitrogen-doped carbon shells. The encapsulated nanoparticles are stable in air and are easily collected by centrifugation, filtration, or magnetic separation. Furthermore, we demonstrate that the catalysts can be reused several times and provide continuously high yields of the olefin-migration product.
- Kramer, S?ren,Mielby, Jerrik,Buss, Kasper,Kasama, Takeshi,Kegn?s, S?ren
-
p. 2930 - 2934
(2017/08/14)
-
- Nickel-Catalyzed Allylic C(sp2)–H Activation: Stereoselective Allyl Isomerization and Regiospecific Allyl Arylation of Allylarenes
-
Stereoselective allyl isomerization and regiospecific allyl arylation reactions of allylarenes with a catalytic system comprising nickel(II) with an aryl Grignard reagent were studied. Both reactions are triggered by allylic internal C(sp2)–H activation by in-situ-formed Ni0, which is inserted into the C–H bond at the 2-position of the allyl moiety without a directing group. The isomerization of allylarene to 1-propenylarene favors the E isomer and proceeds with quantitative conversion. The arylation takes place through oxidative cross-coupling of allylarenes with excess Grignard reagent. It occurs regiospecifically at the position of C(sp2)–H activation and represents a new method for the synthesis of 1,1-disubstituted olefins. The results of deuterium labeling experiments reveal an alkenyl/alkyl mechanism involving allylic internal C(sp2)–H activation and multiple intermolecular 1,2-, 1,3-, and 2,3-hydride shifts. These methods represent new approaches to the functionalization of olefins, and the mechanistic investigations could be helpful for the discovery and design of new strategies for olefin functionalization.
- Wu, Qiang,Wang, Lanlan,Jin, Rizhe,Kang, Chuanqing,Bian, Zheng,Du, Zhijun,Ma, Xiaoye,Guo, Haiquan,Gao, Lianxun
-
p. 5415 - 5422
(2016/11/22)
-
- Method for synthesizing (E)-Anethol and Related Compounds By Cross Coupling Reaction of Potassium alllyltrifluroborate and 4-bromoanisole and aryl halides
-
Methods of producing substituted and non-substituted beta-methyl styrene by a cross-coupling reaction are provided. The disclosure also provides for methods of preparing (E)-Anethol and related compounds by a cross coupling reaction of potassium allyltrifluoroborate and 4-bromoanisole and aryl halides. Compounds, compositions, and methods of treating disorders utilizing beta-methyl styrene are also provided.
- -
-
Page/Page column 4
(2012/01/15)
-
- Remarkable regioselectivity in microwave-enhanced palladium-catalyzed allylation reaction involving allyltrifluoroborates and aryl halides
-
An unprecedented cross-coupling reaction of potassium allyltrifluoroborates and aryl halides to the corresponding trans-β-methylstyrenes in the presence of PdCl2(dtbpf) catalyst under microwave heating was developed.
- Al-Masum, Mohammad,Alam, Shahrina
-
experimental part
p. 5201 - 5204
(2009/12/06)
-
- A convenient synthesis of episulfides and their conversion into alkenes
-
A convenient and stereoselective synthesis of episulfides based on the reaction of readily available S-(β-oxoalkyl) thiophosphate with sodium borohydride and their conversion into alkenes is described.
- Dybowski, Piotr,Skowrońska, Aleksandra
-
p. 1134 - 1136
(2007/10/03)
-
- KINETICS OF ISOMERIZATION OF ALLYLBENZENE AND ITS DERIVATIVES
-
The kinetics of isomerization with migration of the double bond in allylbenzene and its derivatives were measured in the lithium tert-butoxide-N,N-dimethylacetamide and potassium tert-butoxide-tert-butyl alcohol catalytic systems.The composition of the catalytically active particles in these solvents was established.The dependence of the isomerization rate of substitued allylbenzenes on the position and electronic chracteristics of the substituents is described by the Hammett equation.The effects of substituents and the characteristics of the catalytic systems on thekinetics of the ionization of substituted toluenes and the isomerization of substituted allylbenzenes are similar.It is concluded that these reactions have a common mechanism.
- Polkanov, M. A.,Shapiro, I. O.,Chernoplekova, V. A.,Shatenshtein, A. I.
-
p. 1123 - 1127
(2007/10/02)
-