62510-08-1Relevant articles and documents
Photocatalytic Stoichiometric Oxidant-Free Synthesis of Linear Unsaturated Ketones from 1,2-Disubstituted Cyclopropanols
Laktsevich-Iskryk, Marharyta V.,Krech, Anastasiya V.,Zhabinskii, Vladimir N.,Khripach, Vladimir A.,Hurski, Alaksiej L.
, p. 1077 - 1086 (2020/12/14)
A one-step catalytic oxidant-free synthesis of unsaturated ketones from 1,2-disubstituted cyclopropanols is reported. Previously for this transformation, only two- and three-step protocols have been developed. The reaction proceeds under irradiation with visible light in the presence of catalytic amounts of both an acridinium photocatalyst and a cobaloxime complex. 2-Aryl-substituted cyclopropanols react giving α,β-unsaturated ketones, while dehydrogenative ring opening of 2-alkyl-substituted substrates affords mixtures of α,β- and β,γ-enones. The reaction starts with one-electron oxidation of a cyclopropanol to cyclopropyloxy radical, presumably, by the photoexcited acridinium catalyst. We also found that Co(dmgBF 2) 2(MeCN) 2complex under an air atmosphere and irradiation with blue LEDs or upon heating can serve as a hydroxycyclopropane oxidant.
Recyclable Polyisobutylene-Bound HMPA as an Organocatalyst in Recyclable Poly(α-olefin) Solvents
Fu, Ying-Hua,Bergbreiter, David E.
, p. 6050 - 6058 (2020/10/19)
This work describes the synthesis of a PIB-bound hexamethylphosphoramide (HMPA) analog and its applications as a recyclable catalyst in allylation of aldehydes and reduction of enones in a recyclable poly(α-olefin) (PAO) polymeric solvent. Kinetic studies of the allylation reaction show that this PIB-bound HMPA analog is as active as HMPA in dichloromethane and PAO and that this PIB-bound catalyst is comparably reactive in heptane and in a PAO solvent. The PIB-bound HMPA catalyst has high phase selective solubility in PAO versus a polar solvent. By using this catalyst in a nonvolatile separable PAO solvent, this catalyst recyclability can be coupled to solvent recyclability, something that is less feasible in a conventional heptane solvent. The result is good recycling of catalyst and solvent through at least 5 cycles using simple gravity-based liquid/liquid extractions. This is in contrast to HMPA or conventional solvents which are less recyclable.
C?C Bond Formation of Benzyl Alcohols and Alkynes Using a Catalytic Amount of KOtBu: Unusual Regioselectivity through a Radical Mechanism
Kumar, Amit,Janes, Trevor,Chakraborty, Subrata,Daw, Prosenjit,von Wolff, Niklas,Carmieli, Raanan,Diskin-Posner, Yael,Milstein, David
supporting information, p. 3373 - 3377 (2019/02/14)
We report a C?C bond-forming reaction between benzyl alcohols and alkynes in the presence of a catalytic amount of KOtBu to form α-alkylated ketones in which the C=O group is located on the side derived from the alcohol. The reaction proceeds under thermal conditions (125 °C) and produces no waste, making the reaction highly atom efficient, environmentally benign, and sustainable. Based on our mechanistic investigations, we propose that the reaction proceeds through radical pathways.
Kinetic Resolution of β-Hydroxy Carbonyl Compounds via Enantioselective Dehydration Using a Cation-Binding Catalyst: Facile Access to Enantiopure Chiral Aldols
Paladhi, Sushovan,Hwang, In-Soo,Yoo, Eun Jeong,Ryu, Do Hyun,Song, Choong Eui
supporting information, p. 2003 - 2006 (2018/04/16)
A practical and highly enantioselective nonenzymatic kinetic resolution of racemic β-hydroxy carbonyl (aldol) compounds through enantioselective dehydration process was developed using a cation-binding Song's oligoethylene glycol (oligoEG) catalyst with p
Hydrogenation of Ketones and Esters Catalyzed by Pd/C?SiO2
Akchurin,Baibulatov,Dokichev
, p. 195 - 198 (2018/03/26)
Hydrogenation of unsaturated ketones and esters with molecular hydrogen on the 5%Pd/C?SiO2 heterogeneous catalyst has been studied. The reaction direction and yield are determined by the starting compounds structure. Hydrogenation of unsaturated ketones containing phenyl group at the double carbon–carbon atom is accompanied by the reduction of the ketone group into the alcohol one. Hydrogenation of unsaturated esters is accompanied by transesterification.
Zinc mediated direct transformation of propargyl N-hydroxylamines to α,β-unsaturated ketones and mechanistic insight
Das, Prasanta,Hamme, Ashton T.
, p. 1086 - 1089 (2017/03/02)
A Lewis acid catalyzed direct transformation of propargyl N-hydroxylamines to α,β-unsaturated ketones in the presence of aqueous Zn(II)-salts has been described. This investigation also provides a novel observation for the stoichiometric role of Zn-halides over what is known to date for catalytic processes. A thorough mechanistic study has been established based on the experiment using18O-labeled water in optimized reaction conditions; the incorporation of18O in the desired product was also substantiated by HRMS. This methodology is also a mild, inexpensive, and an efficient approach for this unusual conversion.
Kinetic Resolution of Racemic Allylic Alcohols by Catalytic Asymmetric Substitution of the OH Group with Monosubstituted Hydrazines
Yan, Liang,Xu, Jing-Kun,Huang, Chao-Fan,He, Zeng-Yang,Xu, Ya-Nan,Tian, Shi-Kai
supporting information, p. 13041 - 13045 (2016/09/09)
A new strategy has been established for the kinetic resolution of racemic allylic alcohols through a palladium/sulfonyl-hydrazide-catalyzed asymmetric OH-substitution under mild conditions. In the presence of 1 mol % [Pd(allyl)Cl]2, 4 mol % (S)-SegPhos, and 10 mol % 2,5-dichlorobenzenesulfonyl hydrazide, a range of racemic allylic alcohols were smoothly resolved with selectivity factors of more than 400 through an asymmetric allylic alkylation of monosubstituted hydrazines under air at room temperature. Importantly, this kinetic resolution process provided various allylic alcohols and allylic hydrazine derivatives with high enantiopurity.
Ruthenium-catalyzed conjugate hydrogenation of ?±,?2-enones by in situ generated dihydrogen from paraformaldehyde and water
Li, Wanfang,Wu, Xiao-Feng
supporting information, p. 331 - 335 (2015/03/05)
Notwithstanding that the highly selective hydrogenation of ?±,?2-enones to allylic alcohols can be realized by using Noyori's Ru bifunctional system, the selective reduction of the C=C bonds in ?±,?2-enones without touching the C=O bonds still lacks a general, simple, and efficient procedure. Ruthenium-catalyzed conjugate hydrogenation of various ?±,?2-enones to saturated ketones with high selectivity was investigated. The most important feature of this procedure was that hydrogen in situ generated from paraformaldehyde (or formalin) and water was employed as the reductant.
Palladium nanoparticles supported on fibrous-structured silica nanospheres (KCC-1): An efficient and selective catalyst for the transfer hydrogenation of alkenes
Qureshi, Ziyauddin S.,Sarawade, Pradip B.,Albert, Matthias,D'Elia, Valerio,Hedhili, Mohamed N.,K?hler, Klaus,Basset, Jean-Marie
, p. 635 - 642 (2015/03/05)
An efficient palladium catalyst supported on fibrous silica nanospheres (KCC-1) has been developed for the hydrogenation of alkenes and α,β-unsaturated carbonyl compounds, providing excellent yields of the corresponding products with remarkable chemoselectivity. Comparison (high-resolution TEM, chemisorption) with analogous mesoporous (MCM-41, SBA-15) silica-supported Pd nanocatalysts prepared under identical conditions, demonstrates the advantage of employing the fibrous KCC-1 morphology versus traditional supports because it ensures superior accessibility of the catalytically active cores along with excellent Pd dispersion at high metal loading. This morphology ultimately leads to higher catalytic activity for the KCC-1-supported nanoparticles. The protocol developed for hydrogenation is advantageous and environmentally benign owing to the use of HCOOH as a source of hydrogen, water as a solvent, and because of efficient catalyst recyclability and durability. The recycled catalyst has been analyzed by XPS spectroscopy and TEM showing only minor changes in the oxidation state of Pd and in the morphology after the reaction, thus confirming the robustness of the catalyst.
Palladium-catalyzed carbonylative dimerization of styrenes to 1,5-diarylpent-1-en-3-ones
Wu, Xiao-Feng,Neumann, Helfried,Beller, Matthias
supporting information; experimental part, p. 1199 - 1202 (2012/08/08)
A general palladium-catalyzed carbonylative dimerization of styrenes has been developed. Starting from commercial available styrenes, symmetrical 1,5-diarylpent-1-en-3-ones were produced in good to excellent yields (see scheme; dppp=1,3-bis(diphenylphosphino)propane). Copyright
