165754-26-7Relevant academic research and scientific papers
Ternary Catalysis Enabled Three-Component Asymmetric Allylic Alkylation as a Concise Track to Chiral α,α-Disubstituted Ketones
Chang, Wenju,Fu, Xiang,Hu, Wenhao,Kang, Zhenghui,Liang, Yong,Tian, Xue,Xu, Xinfang,Zhao, Wenxuan
, p. 20818 - 20827 (2021/12/17)
Multicomponent reactions that involve interception of onium ylides through Aldol, Mannich, and Michael addition with corresponding bench-stable acceptors have demonstrated broad applications in synthetic chemistry. However, because of the high reactivity and transient survival of these in situ generated intermediates, the substitution-type interception process, especially the asymmetric catalytic version, remains hitherto unknown. Herein, a three-component asymmetric allylation of α-diazo carbonyl compounds with alcohols and allyl carbonates is disclosed by employing a ternary cooperative catalysis of achiral Pd-complex, Rh2(OAc)4, and chiral phosphoric acid CPA. This method represents the first example of three-component asymmetric allylic alkylation through an SN1-type trapping process, which involves a convergent assembly of two active intermediates, Pd-allyl species, and enol derived from onium ylides, providing an expeditious access to chiral α,α-disubstituted ketones in good to high yields with high to excellent enantioselectivity. Combined experimental and computational studies have shed light on the mechanism of this novel three-component reaction, including the critical role of Xantphos ligand and the origin of enantioselectivity.
Dibromination of alkenes with LiBr and H2O2 under mild conditions
Martins, Nayara Silva,Alberto, Eduardo E.
supporting information, p. 161 - 167 (2017/12/28)
Electron-rich and electron-poor alkenes, and alkenes bearing protecting groups can be efficiently and stereoselectively converted to trans-dibromides using LiBr/H2O2 and AcOH as a proton source in 1,4-dioxane. For most substrates addition of 0.1 mol% of PhTeTePh enhances the reaction rate and the yield of the products. Experimental data suggest that the brominating agent prepared in situ is molecular bromine and that LiBr assists the activation of H2O2 allowing bromination to occur using AcOH as a mild proton source in uncatalyzed experiments. Scale-up is feasible: 10.0 mmol of 1-octene was quantitatively converted to 1,2-dibromooctene in one hour of reaction at room temperature.
Electrochemical properties and reactions of organoboronic acid esters containing unsaturated bonds at their α-position
Ohtsuka, Kazuhiro,Inagi, Shinsuke,Fuchigami, Toshio
, p. G23 - G28 (2017/12/26)
Electrochemical analyses of 2-(cynnamyl)boronic acid pinacol ester and (3-phenyl-2-propynyl)boronic acid pinacol ester, and their trimethylsilyl analogues as well as their parent compounds were comparatively studied by cyclic voltammetry measurements. We
Tetrahydroxydiboron-Mediated Palladium-Catalyzed Transfer Hydrogenation and Deuteriation of Alkenes and Alkynes Using Water as the Stoichiometric H or D Atom Donor
Cummings, Steven P.,Le, Thanh-Ngoc,Fernandez, Gilberto E.,Quiambao, Lorenzo G.,Stokes, Benjamin J.
supporting information, p. 6107 - 6110 (2016/06/09)
There are few examples of catalytic transfer hydrogenations of simple alkenes and alkynes that use water as a stoichiometric H or D atom donor. We have found that diboron reagents efficiently mediate the transfer of H or D atoms from water directly onto unsaturated C-C bonds using a palladium catalyst. This reaction is conducted on a broad variety of alkenes and alkynes at ambient temperature, and boric acid is the sole byproduct. Mechanistic experiments suggest that this reaction is made possible by a hydrogen atom transfer from water that generates a Pd-hydride intermediate. Importantly, complete deuterium incorporation from stoichiometric D2O has also been achieved.
Organohalide-catalyzed dehydrative O-alkylation between alcohols: A facile etherification method for aliphatic ether synthesis
Xu, Qing,Xie, Huamei,Chen, Pingliang,Yu, Lei,Chen, Jianhui,Hu, Xingen
supporting information, p. 2774 - 2779 (2015/05/27)
Organohalides are found to be effective catalysts for dehydrative O-alkylation reactions between alcohols, providing selective, practical, green, and easily scalable homo- and cross-etherification methods for the preparation of useful symmetrical and unsymmetrical aliphatic ethers from the readily available alcohols. Mechanistic studies revealed that organohalides are regenerated as reactive intermediates and recycled to catalyze the reactions.
Nanoporous gold catalyst for highly selective semihydrogenation of alkynes: Remarkable effect of amine additives
Yan, Mei,Jin, Tienan,Ishikawa, Yoshifumi,Fujita, Takeshi,Chen, Lu-Yang,Asao, Naoki,Chen, Ming-Wei,Yamamoto, Yoshinori,Minato, Taketoshi,Bao, Ming
supporting information, p. 17536 - 17542,7 (2020/09/16)
We report for the first time the highly selective semihydrogenation of alkynes using the unsupported nanoporous gold (AuNPore) as a catalyst and organosilanes with water as a hydrogen source. Under the optimized reaction conditions, the present semihydrogenation of various terminal- and internal-alkynes affords the corresponding alkenes in high chemical yields and excellent Z-selectivity without any over-reduced alkanes. The use of DMF as solvent, which generates amines in situ, or pyridine as an additive is crucial to suppress the association of hydrogen atoms on AuNPore to form H2 gas, which is unable to reduce alkynes on the unsupported gold catalysts. The AuNPore catalyst can be readily recovered and reused without any loss of catalytic activity. In addition, the SEM and TEM characterization of nanoporosity show that the AuNPore catalyst has a bicontinuous 3D structure and a high density of atomic steps and kinks on ligament surfaces, which should be one of the important origins of catalytic activity.
Pd(OAc)2/dppf as an efficient and highly active catalyst for the allylation of amines, alcohols and carboxylic acids with 1-phenyl-1-propyne
Wagh, Yogesh S.,Sawant, Dinesh N.,Tambade, Pawan J.,Dhake, Kishor P.,Bhanage, Bhalchandra M.
experimental part, p. 2414 - 2421 (2011/04/26)
Pd(OAc)2/1,1′-bis(diphenylphosphino)ferrocene as an efficient, highly active catalyst for the allylation of amines, alcohols and carboxylic acids with 1-phenyl-1-propyne has been developed. The effect of various reaction parameters, such as ligand, time, solvent, temperature, metal: ligand ratio and catalyst concentration on yields of the product were investigated. The optimized procedure works well under mild operating conditions and permits rapid generation of a library for various allylated products.
Allylation of 1-phenyl-1-propyne with N- and O-pronucleophiles using polymer supported triphenylphosphine palladium complex as a heterogeneous and recyclable catalyst
Wagh, Yogesh S.,Sawant, Dinesh N.,Dhake, Kishor P.,Deshmukh, Krishna M.,Bhanage, Bhalchandra M.
experimental part, p. 5676 - 5679 (2011/11/06)
Simple methodology for the allylation of various N- and O-pronucleophiles with 1-phenyl-1-propyne as an allylating agent, using PS-TPP-Pd (polymer supported triphenylphosphine palladium) as a highly active heterogeneous recyclable catalyst has been developed. The protocol is applicable for a wide variety of hindered and functionalized aromatic amines, alcohols, and carboxylic acids. The catalyst exhibited remarkable catalytic activity for five consecutive recycles.
Gas-phase pyrolytic reaction of 4-Aryl-3-buten-2-ols and allyl benzyl ethers: Kinetic and mechanistic study
Al-Etaibi, Alya M.,Al-Awadi, Nouria A.,Ibrahim, Maher R.,Ibrahim, Yehia A.
experimental part, p. 407 - 419 (2010/05/02)
Flash vacuum pyrolysis (FVP) of 4-aryl-3-buten-2-ols [ArCH=CHCH(CHs)OH, where Ar is phenyl, p-MeO, p-Me, p-Cl, p-NO2] gave the corresponding buta-1,3-dien-1-ylbenzene (ArCH=CH-CH=CH2, where Ar is Ph, p-MeO, p-Me, p-Cl, pNO2) and 7-×-1,2-dihydronaphthalene derivatives (where X is H, MeO); FVP of 1-aryl-3benzyloxyl-1-butenes and benzyl cinnamyl ethers [ArCH=CHCH(X)OCH2Ph, where Ar is phenyl, p-MeO, p-Me, p-Cl, X is H, Me, Ph] gave the corresponding but-2-en-l-ylbenzene derivatives (ArCH 2CH=CH-X, where X is H, Me, Ph) together with benzaldehyde. The proposed mechanism of these pyrolytic transformations was supported by kinetic and product analysis.
Palladium-catalyzed regio-and enantio-selective allylic substitution reaction of monosubstituted allyl substrates with benzyl alcohols
Fang, Ping,Ding, Chang-Hua,Hou, Xue-Long,Dai, Li-Xin
scheme or table, p. 1176 - 1178 (2010/11/02)
Regio-and enantio-selectivities in Pd-catalyzed allylic substitution reaction of monosubstituted allylic substrates with substituted benzyl alcohols were realized, affording the corresponding products in high regioselectivity (up to 93/7) and enantioselec
