1121-18-2Relevant academic research and scientific papers
PALLADIUM-CATALYZED SYNTHESIS OF α,β-UNSATURATED KETONES FROM KETONES VIA ALLYL ENOL CARBONATES
Shimizu, Isao,Minami, Ichiro,Tsuji, Jiro
, p. 1797 - 1800 (1983)
Allyl enol carbonates, prepared by quenching ketone enolates with allyl chloroformate, are converted to α,β-unsaturated ketones with Pd(OAc)2-dppe catalyst in CH3CN.
Aqueous Microdroplets Capture Elusive Carbocations
Kumar, Anubhav,Mondal, Supratim,Banerjee, Shibdas
, p. 2459 - 2463 (2021)
Carbocations are short-lived reactive intermediates in many organic and biological reactions that are difficult to observe. This field sprung to life with the discovery by Olah that a superacidic solution allowed the successful capture and nuclear magnetic resonance characterization of transient carbocations. We report here that water microdroplets can directly capture the fleeting carbocation from a reaction aliquot followed by its desorption to the gas phase for mass spectrometric detection. This was accomplished by employing desorption electrospray ionization mass spectrometry to detect a variety of short-lived carbocations (average lifetime ranges from nanoseconds to picoseconds) obtained from different reactions (e.g., elimination, substitution, and oxidation). Solvent-dependent studies revealed that aqueous microdroplets outperform organic microdroplets in the capture of carbocations. We provide a mechanistic insight demonstrating the survival of the reactive carbocation in a positively charged aqueous microdroplet and its subsequent ejection to the gas phase for mass spectrometric analysis.
Oxidation of ketone by palladium(II), α-hydroxyketone synthesis catalyzed by a bimetallic palladium(II) complex
El-Qisairi, Arab K,Qaseer, Hanan A
, p. 50 - 55 (2002)
A bimetallic palladium(II) complex containing a triketone ligand and a bridging dinitrogen ligand oxidizes ketones in aqueous THF to α-hydroxyketone by a direct air oxidation. While the normal synthesis of α-hydroxyketones involves a series of reactions, this synthesis performs the transformation in one step in a catalytic air oxidation. This synthesis does not involve an olefin and is almost unprecedented in transition metal catalysis. Its main virtue is its simplicity and actually it is an enolization reaction. Methanesulfonic acid is used to accelerate the enolization of ketones. The reaction is carried out in the presence of CuCl2 and/or dioxygen only. In particular, it is found that the hydroxyketone formation does not require the presence of CuCl2. Matrix assisted laser desorption ionization (MALDI) and time-of-flight mass spectrometry (TOFMS) are used to record the mass spectra of α-hydroxyketones products. α-Cyano-4-hydroxycinnamic acid (CHCA) matrix promoted the molecular ion detection when 180 pmol of α-hydroxyketones is introduced into the TOFMS.
ENONE FORMATION FROM ALLYL β-KETO ESTERS ALKENYL ELLYL CARBONATES, SILYL ENOL ETHERS, AND ENOL ACETATES BY THE PHOSPHINE-FREE PALLADIUM CATALYST
Tsuji, Jiro,Minami, Ichiro,Shimizu, Isao,Kataoka, Hideaki
, p. 1133 - 1136 (1984)
The effect of phosphine ligands on the palladium catalyzed enone formation from allyl β-keto esters, alkenyl allyl carbonates, silyl enol ethers, and enol acetates has been reinvestigated, and clean enone formation was observed by a phosphine-free palladium catalyst.
A NOVEL PALLADIUM-CATALYZED PREPARATIVE METHOD OF α,β-UNSATURATED KETONES AND ALDEHYDES FROM SATURATED KETONES AND ALDEHYDES VIA THEIR SILYL ENOL ETHERS
Tsuji, Jiro,Minami, Ichiro,Shimizu, Isao
, p. 5635 - 5638 (1983)
Silyl enol ethers prepared from saturated ketones and aldehydes can be converted to α,β-unsaturated ketones and aldehydes by the reaction of allyl carbonate in the presence of palladium-phosphine complexes as a catalyst.The selection of solvent is crucial and nitriles are most effective as the solvent.
ONE-STEP SYNTHESIS OF α,β-UNSATURATED KETONES BY THE REACTION OF ENOL ACETATES WITH ALLYL METHYL CARBONATE CATALYZED BY PALLADIUM AND TIN COMPOUNDS
Tsuji, Jiro,Minami, Ichiro,Shimizu, Isao
, p. 5639 - 5640 (1983)
Enol acetates derived from saturated ketones are converted to α,β-unsaturated ketones by heating with allyl methyl carbonate in MeCN by bimetallic catalysis of palladiumphosphine complex and tin methoxide.
Syntesis of 2-Cycloalken-1-ones
Shimazaki, Makoto,Huang, Zhi-Hui,Goto, Mikiko,Suzuki, Noriko,Ohta, Akihiro
, p. 677 - 678 (1990)
The bromination of 2-alkyl- and 2-phenyl-1-cycloalkanones with N-bromosuccinimide and subsequent dehydrobromination with aniline gave the corresponding 2-cycloalken-1-ones.
Improved robustness of heterogeneous Fe-non-heme oxidation catalysts: A catalytic and EPR study
Bilis,Stathi,Mavrogiorgou,Deligiannakis,Louloudi
, p. 376 - 389 (2014)
There is currently a rarity in production and in-depth catalytic study of heterogeneous non-heme Fe catalysts. Herein, two heterogeneous catalysts have been synthesized by covalent grafting of non-heme Fe-complexes, DPEIFe IIICl and HFEIFeIIICl, on SiO2. The catalytic performance of the obtained DPEIFeIII@SiO2 and HFEIFe III@SiO2 materials has been systematically studied for catalytic oxidation of cyclohexene. The catalytic data show that the present non-heme Fe catalysts are functional and can achieve higher activity compared to other non-heme Fe reported so far in the literature. Importantly, the heterogeneneous catalysts show a remarkable robustness and improved oxidative stability vs. the homogeneous ones. Studies by UV-vis and EPR reveal a common mechanistic pattern: CH3CN interacts with the Fe-atom promoting the formation of a Low-Spin (S = 1/2) intermediate, in the presence of H 2O2, probably a FeIII-OOH hydroperoxide. The role of radical intermediates was investigated in detail by spin-trapping techniques. Finally, taking into account the nature of oxidation products, a consistent catalytic mechanism, valid for both homogeneous and heterogeneous catalysts, is discussed.
Total Synthesis and Structure Revision of Halioxepine
Poock, Caroline,Kalesse, Markus
, p. 1615 - 1619 (2020/12/23)
The first total synthesis of halioxepine is accomplished using a 1,4-addition for constructing the quaternary center at C10 and a halo etherification for the generation of the tertiary ether at C7. The correct structure of halioxepine was determined by assembling different enantiomeric building blocks and by changing the relative configuration between C10 and C15.
CeO2-Supported Pd(II)-on-Au Nanoparticle Catalyst for Aerobic Selective α,β-Desaturation of Carbonyl Compounds Applicable to Cyclohexanones
Jin, Xiongjie,Mizuno, Noritaka,Takei, Daisuke,Yabe, Tomohiro,Yamaguchi, Kazuya,Yatabe, Takafumi
, p. 5057 - 5063 (2020/05/27)
Direct selective desaturation of carbonyl compounds to synthesize α,β-unsaturated carbonyl compounds represents an environmentally benign alternative to classical stepwise procedures. In this study, we designed an ideal CeO2-supported Pd(II)-on-Au nanoparticle catalyst (Pd/Au/CeO2) and successfully achieved heterogeneously catalyzed selective desaturation of cyclohexanones to cyclohexenones using O2 in air as the oxidant. Besides cyclohexenones, various bioactive enones can also be synthesized from the corresponding saturated ketones under open air conditions in the presence of Pd/Au/CeO2. Preliminary mechanistic studies revealed that α-C-H bond cleavage in the substrates is the turnover-limiting step of this desaturation reaction.
