cas 35845-66-0, (E)-1-phenylbut-2-en-1-one

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Modular access to 1,2-allenyl ketones based on a photoredox-catalysed radical-polar crossover process
Herein, a new protocol dealing with the preparation of 1,2-allenyl ketones has been successfully developedviathe reactions of enynes with radicals enabled by dual photoredox/copper catalysis. Based on the results of a deuteration experiment and the competition reaction between cyclopropanation and allenation, the mechanism based on a photoredox-neutral-catalysed radical-polar crossover process has been proposed. Synthetic applications of allenes have also been demonstrated.
Du, Chan,Fang, Jianghua,Fang, Yewen,Lei, Wan,Li, Yan,Liu, Yongjun
supporting information
p. 8502 - 8506
(2021/10/20)

N-Heterocyclic Iod(az)olium Salts – Potent Halogen-Bond Donors in Organocatalysis
This article describes the application of N-heterocyclic iod(az)olium salts (NHISs) as highly reactive organocatalysts. A variety of mono- and dicationic NHISs are described and utilized as potent XB-donors in halogen-bond catalysis. They were benchmarked in seven diverse test reactions in which the activation of carbon- and metal-chloride bonds as well as carbonyl and nitro groups was achieved. N-methylated dicationic NHISs rendered the highest reactivity in all investigated catalytic applications with reactivities even higher than all previously described monodentate XB-donors based on iodine(I) and (III) and the strong Lewis acid BF3.
Boelke, Andreas,Kuczmera, Thomas J.,Lork, Enno,Nachtsheim, Boris J.
supporting information
p. 13128 - 13134
(2021/08/09)

Mild Darzens Annulations for the Assembly of Trifluoromethylthiolated (SCF3) Aziridine and Cyclopropane Structures
We report mild new annulation approaches to trisubstituted trifluoromethylthiolated (SCF3) aziridines and cyclopropanes via Darzens inspired protocols. The products of these anionic annulations, rarely studied previously, possess attractive features rendering them valuable building blocks for synthesis platforms. In this study, trisubstituted acetophenone nucleophiles bearing SCF3 and bromine substituents in their α position were shown to undergo [2 + 1] annulations with vinyl ketones and tosyl-protected imines under mild reaction conditions.
Delost, Michael D.,Njardarson, Jon T.
supporting information
p. 6121 - 6125
(2021/08/16)

Photocatalytic Stoichiometric Oxidant-Free Synthesis of Linear Unsaturated Ketones from 1,2-Disubstituted Cyclopropanols
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.
Laktsevich-Iskryk, Marharyta V.,Krech, Anastasiya V.,Zhabinskii, Vladimir N.,Khripach, Vladimir A.,Hurski, Alaksiej L.
p. 1077 - 1086
(2020/12/14)

Photoredox/Cobalt Dual-Catalyzed Decarboxylative Elimination of Carboxylic Acids: Development and Mechanistic Insight
Recently, dual-catalytic strategies towards the decarboxylative elimination of carboxylic acids have gained attention. Our lab previously reported a photoredox/cobaloxime dual catalytic method that allows the synthesis of enamides and enecarbamates directly from N-acyl amino acids and avoids the use of any stoichiometric reagents. Further development, detailed herein, has improved upon this transformation's utility and further experimentation has provided new insights into the reaction mechanism. These new developments and insights are anticipated to aid in the expansion of photoredox/cobalt dual-catalytic systems.
Cartwright, Kaitie C.,Joseph, Ebbin,Comadoll, Chelsea G.,Tunge, Jon A.
p. 12454 - 12471
(2020/09/09)

Enantioselective N -Alkylation of Nitroindoles under Phase-Transfer Catalysis
An asymmetric phase-transfer-catalyzed N -alkylation of substituted indoles with various Michael acceptors was studied. Acidities of nitroindoles were determined in acetonitrile by UV-Vis spectrophotometric titration. There was essentially no correlation between acidity and reactivity in the aza-Michael reaction. The position of the nitro group on the indole ring was essential to control the stereoselectivity of the reaction. Michael adducts were obtained in high yields and moderate enantioselectivities in the reaction between 4-nitroindole and various Michael acceptors in the presence of cinchona alkaloid based phase-transfer catalysts. In addition to outlining the scope and limitations of the method, the geometries of the transition states of the reaction were calculated.
Erkman, Kristin,J?rving, Ivar,K?ster, Kristjan,Kanger, T?nis,Leito, Ivo,Mart?nova, Jevgenija,Metsala, Andrus,Saame, Jaan,Trubits?n, Dmitri
p. 1047 - 1059
(2020/04/01)

Electrochemical C(sp 3)-H Fluorination
A simple and robust method for electrochemical alkyl C-H fluorination is presented. Using a simple nitrate additive, a widely available fluorine source (Selectfluor), and carbon-based electrodes, a wide variety of activated and unactivated C-H bonds are converted into their C-F congeners. The scalability of the reaction is also demonstrated with a 100 gram preparation of fluorovaline.
Baran, Phil S.,Chen, Longrui,Chen, Miao,Hoshikawa, Tamaki,Kawamata, Yu,Li, Chao,Mykhailiuk, Pavel,Nakamura, Hugh,Peters, Byron K.,Reisberg, Solomon H.,Shibuguchi, Tomoyuki,Takahira, Yusuke
supporting information
p. 1178 - 1182
(2019/06/08)

Organocatalytic Enantioselective Selenosulfonylation of a C-C Double Bond to Form Two Stereogenic Centers in an Aqueous Medium
Organocatalytic selenosulfonylation of the C-C double bond of α,β-unsaturated ketones to construct two contiguous stereogenic centers in an aqueous medium was described. A series of α-selenyl and β-sulfonyl ketones with various functional groups were synthesized in good yields and enantioselectivities with saturated NaCl solution as the solvent. In addition, this protocol had been successfully scaled up to a decagram scale via a simple workup procedure.
Chen, Zhili,Hu, Fangli,Huang, Shengli,Zhao, Zhengxing,Mao, Hui,Qin, Wenling
p. 8100 - 8111
(2019/06/17)

Synthesis of Enones and Enals via Dehydrogenation of Saturated Ketones and Aldehydes
A general, efficient and economic palladium-catalyzed dehydrogenation to form enones or enals has been developed. The approach possesses extremely broad substrate scope including various linear or cyclic saturated ketones and aldehydes. The protocol is ligand-free, and molecular oxygen is used as the sole clean oxidant in the reaction. Due to mild reaction conditions, good functional group compatibility, and versatile utilities of enones and enals, the method can be applied in the late-stage synthesis of natural products, pharmaceuticals and fine chemicals. (Figure presented.).
Pan, Gao-Fei,Zhu, Xue-Qing,Guo, Rui-Li,Gao, Ya-Ru,Wang, Yong-Qiang
p. 4774 - 4783
(2018/11/10)

Activation of Michael Acceptors by Halogen-Bond Donors
Extending earlier studies on iodine catalysis, experimental investigations show that various halogen-bond donors can also be employed to accelerate the Michael addition between trans -crotonophenone and indole. Solvent as well as counteranion effects have been analyzed, and kinetic and computational investigations provide additional insights into the mode of activation.
Von Der Heiden, Daniel,Detmar, Eric,Kuchta, Robert,Breugst, Martin
supporting information
p. 1307 - 1313
(2017/12/08)

Indium(III)-Catalyzed Hydration and Hydroalkoxylation of α,β-Unsaturated Ketones in Aqueous Media
The hydration of α,β-unsaturated ketones with water proceeded efficiently in the presence of In(OTf)3 (20 mol%) in aqueous media to afford synthetically versatile β-hydroxyketones in moderate to good yields with good functional group compatibility. The method also can be extended to the hydroalkoxylation of α,β-unsaturated ketones with various alcohols for the efficient synthesis of β-alkoxyketones as well as tetrahydrofuran derivatives. (Figure presented.).
Yun, Jin-Jin,Zhi, Man-Ling,Shi, Wen-Xiao,Chu, Xue-Qiang,Shen, Zhi-Liang,Loh, Teck-Peng
supporting information
p. 2632 - 2637
(2018/05/30)

Chromium(III)-Catalyzed Addition of Water and Alcohol to α,β-Unsaturated Ketones for the Synthesis of β-Hydroxyl and β-Alkoxyl Ketones in Aqueous Media
An efficient chromium(III) chloride-catalyzed Michael-type reaction of water or alcohol with α,β-unsaturated ketones is developed. A variety of α,β-unsaturated ketones effectively reacted with either water or alcohols to give the corresponding β-hydroxyl ketones or β-alkoxyl ketones in modest to high yields with excellent compatibility to various functional groups. The approach was further utilized for the preparation of synthetically useful compounds containing tetrahydrofuran skeleton.
Yun, Jin-Jin,Liu, Xuan-Yu,Deng, Wei,Chu, Xue-Qiang,Shen, Zhi-Liang,Loh, Teck-Peng
p. 10898 - 10907
(2018/09/06)

Reaction Mechanism of Iodine-Catalyzed Michael Additions
Molecular iodine, an easy to handle solid, has been successfully employed as a catalyst in different organic transformations for more than 100 years. Despite being active even in very small amounts, the origin of this remarkable catalytic effect is still unknown. Both a halogen bond mechanism as well as hidden Br?nsted acid catalysis are frequently discussed as possible explanations. Our kinetic analyses reveal a reaction order of 1 in iodine, indicating that higher iodine species are not involved in the rate-limiting transition state. Our experimental investigations rule out hidden Br?nsted acid catalysis by partial decomposition of I2 to HI and suggest a halogen bond activation instead. Finally, molecular iodine turned out to be a similar if not superior catalyst for Michael additions compared with typical Lewis acids.
Von Der Heiden, Daniel,Bozkus, Seyma,Klussmann, Martin,Breugst, Martin
p. 4037 - 4043
(2017/04/28)

An iron-catalyzed hydroalkylation reaction of α,β-unsaturated ketones with ethers
A general strategy for the hydroalkylation of vinyl ketones using ethers catalyzed by an iron catalyst is described. This catalytic method permits direct transformation of easily accessible and abundant precursors into highly substituted, structurally diverse and functionally concentrated products.
Lan, Yun,Fan, Pei,Liu, Xiao-Wei,Meng, Fei-Fan,Ahmad, Tanveer,Xu, Yun-He,Loh, Teck-Peng
supporting information
p. 12353 - 12356
(2017/11/20)

Halogen-bonded iodonium ion catalysis: A route to α-hydroxy ketones: Via domino oxidations of secondary alcohols and aliphatic C-H bonds with high selectivity and control
A domino synthesis of α-hydroxy ketones has been developed from benzylic secondary alcohols employing catalytic iodonium ions stabilized by DMSO. The reaction proceeds through an unprecedented sequential oxidation of alcohols to ketone and its α-hydroxylation in a controlled manner. The spectroscopic evidence establishes the possibility of formation of a stable halogen-bonded adduct between DMSO and iodonium ions.
Guha, Somraj,Kazi, Imran,Mukherjee, Pranamita,Sekar, Govindasamy
supporting information
p. 10942 - 10945
(2017/10/13)

Copper-Catalyzed Carbenoid Insertion Reactions of α-Diazoesters and α-Diazoketones into Si-H and S-H Bonds
An efficient copper-catalyzed carbenoid insertion reaction of α-diazo carbonyl compounds into Si-H and S-H bonds was developed. A wide range of α-silylesters and α-thioesters was obtained in high yields (up to 98%) from α-diazoesters using 5 mol% of a simple copper(I) salt as catalyst. Using 0.05 mol% of the same catalyst, α-diazoketones led to α-silylketones in low to good yields (up to 70%).
Keipour, Hoda,Jalba, Angela,Delage-Laurin, Léo,Ollevier, Thierry
p. 3000 - 3010
(2017/03/23)

Bifunctional Thiourea-Catalyzed Stereoablative Retro-Sulfa-Michael Reaction: Concise and Diastereoselective Access to Chiral 2,4-Diarylthietanes
Owing to the chiral recognition capacity of bifunctional thioureas, a stereoablative retro-sulfa-Michael reaction has been developed. Utilization of a biphasic system enabled us to render the process catalytic. The usefulness of this methodology was further illustrated by the diastereoselective synthesis of all possible stereoisomers of 2,4-diarylthiethanes.
Bacsó, András,Szigeti, Mariann,Varga, Szilárd,Soós, Tibor
p. 429 - 439
(2016/12/24)

Palladium(II)-Catalyzed Dehydroboration via Generation of Boron Enolates
The PdII-catalyzed dehydroboration of boron enolates generated from ketones and 9-iodo-9-borabicyclo[3.3.1]nonane was achieved, providing a synthetically versatile protocol from ketones to α,β-unsaturated ketones. The PdIIcompound employed in this reaction worked catalytically in the presence of Cu(OAc)2. The high trans-selectivity of the olefinic moiety was observed. Aryl halide moieties (-Br and -Cl) remained intact for this reaction in spite of the presence of a Pd species. An ester substrate could also be applied when a stoichiometric amount of PdIIwas used. The crossover reactions using boron and silyl enolates revealed that the oxidation reaction is much faster than the Saegusa-Ito reaction.
Sakamoto, Yuki,Amaya, Toru,Suzuki, Takeyuki,Hirao, Toshikazu
p. 18686 - 18689
(2016/12/26)

Preparation, Antiepileptic Activity, and Cardiovascular Safety of Dihydropyrazoles as Brain-Penetrant T-Type Calcium Channel Blockers
A series of dihydropyrazole derivatives was developed as potent, selective, and brain-penetrating T-type calcium channel blockers. An optimized derivative, compound 6c, was advanced to in vivo studies, where it demonstrated efficacy in the WAG/Rij rat model of generalized nonconvulsive, absence-like epilepsy. Compound 6c was not efficacious in the basolateral amygdala kindling rat model of temporal lobe epilepsy, and it led to prolongation of the PR interval in ECG recordings in rodents.
Remen, Lubos,Bezen?on, Olivier,Simons, Lloyd,Gaston, Rick,Downing, Dennis,Gatfield, John,Roch, Catherine,Kessler, Melanie,Mosbacher, Johannes,Pfeifer, Thomas,Grisostomi, Corinna,Rey, Markus,Ertel, Eric A.,Moon, Richard
supporting information
p. 8398 - 8411
(2016/10/03)

A convenient synthesis of 4-alkyl-3-benzoylpyrroles from α,β-unsaturated ketones and tosylmethyl isocyanide
A convenient synthesis of 4-alkyl-3-benzoyl pyrrole was achieved from α,β-unsaturated ketones and tosylmethyl isocyanide in the presence of mild base LiOH·H2O. This method is very economical and was successfully utilized for the synthesis of various 4-alkyl-3-benzoylpyrrole derivatives with good to excellent yields.
Kumar, Kapil,More, Shital S.,Goyal, Sandeep,Gangar, Mukesh,Khatik, Gopal L.,Rawal, Ravindra K.,Nair, Vipin A.
p. 2315 - 2319
(2016/05/10)

Carbonylative coupling of allylic acetates with aryl boronic acids
The first allylic carbonylation reaction of allylic acetates with aryl boronic acids under carbon monoxide has been developed. Using Pd-PCy3 as a catalyst, a wide spectrum of allylic acetates was carbonylated in the presence of various aryl boronic acids, affording α,β-unsaturated aryl ketones in good to excellent yields. Preliminary studies indicate that carbon monoxide always inserts at the least substituted terminal allylic carbon and the resulting β,γ-unsaturated aryl ketones generally isomerise to the ketones obtained.
Ma, Wei,Xue, Dong,Yu, Ting,Wang, Chao,Xiao, Jianliang
supporting information
p. 8797 - 8800
(2015/05/20)

Trans-cis isomerization of vinylketones through triplet 1,2-biradicals
The irradiation of trans-vinylketones 1a-c yields the corresponding cis isomers 2a-c. Laser flash photolysis of 1a and 1b with 308 and 355 nm lasers results in their triplet ketones (T1K of 1), which rearrange to form triplet 1,2-biradicals 3a and 3b, respectively, whereas irradiation with a 266 nm laser produces their cis-isomers through singlet reactivity. Time-resolved IR spectroscopy of 1a with 266 nm irradiation confirmed that 2a is formed within the laser pulse. In comparison, laser flash photolysis of 1c with a 308 nm laser showed only the formation of 2c through singlet reactivity. At cryogenic temperatures, the irradiation of 1 also resulted in 2. DFT calculations were used to aid in the characterization of the excited states and biradicals involved in the cis-trans isomerization and to support the mechanism for the cis-trans isomerization on the triplet surface.
Ranaweera, R. A. A. Upul,Scott, Tianeka,Li, Qian,Rajam, Sridhar,Duncan, Alexander,Li, Rui,Evans, Anthony,Bohne, Cornelia,Toscano, John P.,Ault, Bruce S.,Gudmundsdottir, Anna D.
p. 10433 - 10447
(2015/03/14)

Oxa-Michael addition promoted by the aqueous sodium carbonate
An efficient Michael addition of alcohols to activated alkenes promoted by sodium carbonate with water as reaction medium has been developed. The reaction provides a general, economical and environmentally friendly approach for the synthesis of β-alkoxycarbonyl compounds.
Guo, Shi-Huan,Xing, Sheng-Zhu,Mao, Shuai,Gao, Ya-Ru,Chen, Wen-Liang,Wang, Yong-Qiang
supporting information
p. 6718 - 6720
(2014/12/11)

Synthesis of Z-alkenes from Rh(I)-catalyzed olefin isomerization of β,γ-unsaturated ketones
Developing olefin isomerization reactions to reach kinetically controlled Z-alkenes is challenging because formation of trans-alkenes is thermodynamically favored under the traditional catalytic conditions using acids, bases, or transition metals as the catalysts. A new synthesis of Z-alkenes from Rh(I)-catalyzed olefin isomerization of β,γ-unsaturated ketones to α,β-unsaturated ketones was developed, providing an easy and efficient way to access various Z-enones.
Zhuo, Lian-Gang,Yao, Zhong-Ke,Yu, Zhi-Xiang
p. 4634 - 4637
(2013/10/08)

Synthesis and properties of BF2-3,3′- dimethyldiarylazadipyrromethene near-infrared fluorophores
The first synthesis of both organic and aqueous soluble BF2 chelated 3,3′-dimethyl-5,5′-diarylazadipyrromethenes has been achieved. The fluorophores are emissive in organic and aqueous solvents with high quantum yields in the key biological near-infrared (NIR) spectral region of 675-700 nm. Following efficient cellular uptake from aqueous media the fluorophore can be readily visualized with confocal microscopy.
Wu, Dan,O'Shea, Donal F.
p. 3392 - 3395
(2013/07/26)

Palladium catalyzed cyclizations of oxime esters with 1,2-disubstituted alkenes: Synthesis of dihydropyrroles
Pd-catalyzed cyclizations of oxime esters with 1,2-dialkylated alkenes provide an entry to chiral dihydropyrroles. Substrate and catalyst controlled strategies for selective product formation (vs alternative pyrroles) are outlined.
Race, Nicholas J.,Bower, John F.
supporting information
p. 4616 - 4619
(2013/09/24)

Decarboxylative allylation of arylglyoxylic acids with allyl alcohol
A decarboxylative allylation of arylglyoxylic acids with allyl alcohol has been developed. In the presence of catalytic amounts of Pd(dba) 2 and PPh3, the substrates are in an esterification equilibrium with the allyl arylglyoxylates, which are continuously decarboxylated to give α,β-unsaturated ketones along with CO2 and water as the only byproducts.
Grünberg, Matthias F.,Goo?en, Lukas J.
p. 140 - 143
(2013/10/01)

PROTEIN CROSSLINKING INHIBITOR AND USE OF THE SAME
The present invention relates to: a ketone compound having transglutaminase-inhibiting activity, which is represented by the following Formula 1, 2, or 3: wherein R1 is a substituted or unsubstituted aryl or heterocyclyl group, R2, R3, and R4 are hydrogen atoms, n is 2, X is halogen, R5 and R6 independently represent a hydrogen atom or a substituted or unsubstituted C1-C10 alkyl, aryl, or aralkyl group, wherein R5 and R6 are not hydrogen atoms at the same time, or R5 and R6 may be taken together to form a saturated or unsaturated and substituted or unsubstituted heterocyclyl group containing a nitrogen atom (N); an inhibitor of protein crosslinking comprising the compound; and a composition for preventing or treating a protein-crosslinking causative disease, which comprises the compound or the protein crosslinking inhibitor.
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(2012/11/08)

InCl3/Me3SiCl-catalyzed direct michael addition of enol acetates to α,β-unsaturated ketones
The direct Michael addition of enol acetates to α,β-unsaturated ketones was achieved using a combination of Lewis acid catalysts, InCl 3 and Me3SiCl, which furnished stable enol-form products that could be further transformed into functionalized 1,5-diketones by reactions with various electrophiles.
Onishi, Yoshiharu,Yoneda, Yuki,Nishimoto, Yoshihiro,Yasuda, Makoto,Baba, Akio
supporting information
p. 5788 - 5791
(2013/01/15)

One-Step Synthesis Method of 2,9-Dimethyl-4,7-Diphenyl-1,10- Phenanthroline
This invention, which belongs to the field of organic synthesis, involves “One-step synthetic method of 2,9-dimethyl-1,7-diphenyl-1,10-phenanthroline”. This method uses O-phenylenediamine and formula III to react under the condition of mixed-shrinking agent, the synthesis can be completed in one step, the stated mixed-shrinking agent is mixture of hydrochloric acid and organic acid. The organic acid serves as phase transfer catalyst and shrinking agent, meanwhile, as buffer reagent, organic acid reduces polymerization of III, and side products as well. The products gained are of high purity and the reaction is mild and easy to control. Since there is no polluting material added and generated, the waste is safe to discharge. In the after treatment of reaction, ketone solvent is used to reduce separation step and product lost, thus improving yield.
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(2012/07/13)

Decarboxylative allylation of glyoxylic acids with diallyl carbonate
A catalyst system consisting of Pd(PPh3)4 and P(pTol)3 was found to effectively promote the intermolecular decarboxylative coupling of α-oxocarboxylic acids with diallyl carbonate to give α,β-unsaturated ketones. The key advantage of the new reaction protocol is that preformation of the allyl esters is not required. The reaction is believed to proceed via phosphane-mediated decarboxylation of the α-oxocarboxylates, leading to acyl anion equivalents that are allylated within the coordination sphere of the palladium catalyst. Under the reaction conditions, the double bond then migrates into conjugation with the carbonyl group. Copyright
Manjolinho, Filipe,Gruenberg, Matthias F.,Rodriguez, Nuria,Goossen, Lukas J.
supporting information; experimental part
p. 4680 - 4683
(2012/10/08)

Asymmetric hydrocyanation of α,β-unsaturated ketones into β-cyano ketones with the [Ru(phgly)2(binap)]/C6H 5OLi catalyst system
Enantioselective conjugate addition of HCN to α,β-unsaturated ketones catalyzed by the combined system of [Ru{(S)-phgly}2{(S)- binap}] and C6H5OLi has afforded β-cyano ketones in high yield (see scheme). No detectable amount of the corresponding 1,2-adduct was produced and tert-C4H9OCH3 was the solvent of choice. The cyanation was conducted with a substrate-to-catalyst molar ratio in the range of 200:1-1000:1 at -20-0°C. Copyright
Kurono, Nobuhito,Nii, Noriyuki,Sakaguchi, Yusuke,Uemura, Masato,Ohkuma, Takeshi
supporting information; experimental part
p. 5541 - 5544
(2011/07/08)

Synthesis of α,β-unsaturated ketones by Pd-catalyzed decarboxylative allylation of α-oxocarboxylates
A palladium/p-tolylphosphine system has been developed that catalyzes the extrusion of carbon dioxide from α-oxocarboxylic acid allyl esters, leading to α,β-unsaturated ketones (see scheme). The palladium complex activates the substrate and mediates the carbon-carbon bond formation to give allyl ketones, and subsequent double bond shift to the α,β position. The actual decarboxylation step with formation of the acyl nucleophile is promoted by phosphine.
Rodriguez, Nuria,Manjolinho, Filipe,Gruenberg, Matthias F.,Goossen, Lukas J.
supporting information; experimental part
p. 13688 - 13691
(2012/01/15)

Structural study-guided development of versatile phase-transfer catalysts for asymmetric conjugate additions of cyanide
Unprecedented phase-transfer catalysts for the first example of an organocatalytic asymmetric conjugate addition of cyanide with acetone cyanohydrin are reported (see scheme). Utilizing an accessible cupreidinium salt and a cyanation reagent suitable for industrial scale, this reaction holds significant promise for practical asymmetric synthesis. The catalysts were developed as a result of key structural insights gained by X-ray analysis. Copyright
Provencher, Brian A.,Bartelson, Keith J.,Liu, Yan,Foxman, Bruce M.,Deng, Li
p. 10565 - 10569
(2011/12/05)

Stabilized α-helix-catalyzed enantioselective epoxidation of α,β-unsaturated ketones
(Equation Presented). Chiral cyclic α-amino acid containing oligopeptide catalyzed highly enantioselective epoxidation of α,β-unsaturated ketones and the α-helical secondary structure of the peptide catalyst were revealed by X-ray crystallographic analysis.
Nagano, Masanobu,Doi, Mitsunobu,Kurihara, Masaaki,Suemune, Hiroshi,Tanaka, Masakazu
supporting information; experimental part
p. 3564 - 3566
(2010/10/02)

N-heterocyclic carbene-catalyzed conjugate additions of alcohols
An efficient intermolecular conjugate addition of alcohols to activated alkenes catalyzed by N-heterocyclic carbenes has been developed. With 5 mol % of the free carbene derived from IMes?HCl, unsaturated ketones and esters are competent substrates, and a variety of primary and secondary alcohols can be employed as the nucleophile. No oligomerization is observed under these mild conditions for effective hydroalkoxylation. In addition to reactions with activated alkenes, IMes catalyzes the formation of vinyl ethers through the 1,4-addition of alcohols to ynones and promotes tandem conjugate addition/Michael cascade reactions. Preliminary data support a Bronsted base mechanism with the free carbene.
Phillips, Eric M.,Riedrich, Matthias,Scheidt, Karl A.
supporting information; experimental part
p. 13179 - 13181
(2010/11/05)

A simple and versatile re-catalyzed meyer-schuster rearrangement of propargylic alcohols to α,β-unsaturated carbonyl compounds
The development of a general catalytic procedure for the rapid and efficient 1,3-rearrangement of free secondary and tertiary propargylic alcohols to the corresponding α,β-unsaturated carbonyl compounds using available [ReOCl3(OPPh3)-(SMe2)] complex, was reported. The reaction was carried out under neutral environmental conditions with no racemization of potentially enolizable stereocenters with virtually complete E stereoselectivity. The reaction under dimethoxyethane, proceeded at the lower rate than in THF, but with reduced by-products and the yield obtained were highly significant. The reaction was reported to increase constantly at the expense of the (Z)-isomer 2b, where the double bong isomerization was attributed to a catalytic effect of the rhenium complex. The resulted new version of Meyer-Schuster rearrangement will find enormous application in organic synthesis to develop one-pot multistep reaction sequences.
Stefanoni, Massimo,Luparia, Marco,Porta, Alessio,Zanoni, Giuseppe,Vidari, Giovanni
experimental part
p. 3940 - 3944
(2009/12/03)

Synthesis of 1,2-diketones by the transition metal-catalyst-free reaction of α-oxo acid chlorides or oxalyl chloride with organostannanes
(Chemical Equation Presented) The reaction of an α-oxo acid chloride with an organostannane proceeds transition metal-catalyst-free to afford a 1,2-diketone in an excellent yield. In addition, a sequence comprising pretreatment of oxalyl chloride with an
Kashiwabara, Taigo,Tanaka, Masato
supporting information; experimental part
p. 3958 - 3961
(2009/09/26)

Lewis base-catalyzed conjugate reduction and reductive aldol reaction of α,β-unsaturated ketones using trichlorosilane
Lewis bases such as Ph3P=O and HMPA catalyze the 1,4-reduction of α,β-unsaturated ketones with trichlorosilane, and because the 1,2-reduction of aldehydes scarcely proceeded under the conditions, one-pot reductive aldol reactions with aldehydes were successfully achieved; preliminary studies using a chiral Lewis base revealed a high potential for enantioselective catalysis. The Royal Society of Chemistry.
Sugiura, Masaharu,Sato, Norimasa,Kotani, Shunsuke,Nakajima, Makoto
supporting information; experimental part
p. 4309 - 4311
(2009/03/12)

Mo-Au combo catalysis for rapid 1,3-rearrangement of propargyl alcohols into α,ss-unsaturated carbonyl compounds
The combination of Mo and cationic Au catalysts dramatically accelerated the rearrangement of diverse propargyl alcohols, which includes a short reaction time, mild conditions, and high product yields. A practical application to the highly challenging primary propargyl alcohols and the N-alkynyl amides is achieved.
Egi, Masahiro,Yamaguchi, Yoshiko,Fujiwara, Noboru,Akai, Shuji
supporting information; experimental part
p. 1867 - 1870
(2009/04/18)

Difluoro-λ3-bromane-induced oxidative carbon-carbon bond-forming reactions: Ethanol as an electrophilic partner and alkynes as nucleophiles
Reported here for the first time are the oxidative couplings of alkynes and primary alcohols yielding conjugated enones. Although the BF3-catalyzed reaction of terminal alkynes with p-trifluoromethylphenyl(difluoro)-λ3-bromane results in the fluoro-λ3-bromanation of triple bonds to afford (E)-β-fluorovinyl-λ3-bromanes, reaction of an alkyne with the difluoro-λ3-bromane in the presence of an alcohol and BF3-Et2O affords directly conjugated enones in good yields. The reaction proceeds in a highly stereo- and regioselective manner under metal-free conditions. Interestingly, no formation of enones was detected, when difluoro-λ3-iodane p-CF3C6H4IF2 was used instead of the λ3-bromane. A mechanism involving a λ3-bromane-induced oxidation of an alcohol to an aldehyde, [2 + 2] cyclization with alkynes yielding 2H-oxetes, and finally the electrocyclic ring opening is discussed. Copyright
Ochiai, Masahito,Yoshimura, Akira,Mori, Takeshi,Nishi, Yoshio,Hirobe, Masaya
p. 3742 - 3743
(2008/09/21)

Gold-catalyzed efficient formation of α,β-unsaturated ketones from propargylic acetates
An efficient gold-catalyzed method for the preparation of α,β-unsaturated ketones from propargylic acetates has been developed. Under mild reaction conditions, β-monosubstituted enones were formed mostly with excellent E-selectivity. β,β-Disubstituted enones can be prepared from propargylic acetates derived from ketones. The high efficiency and mild nature of this reaction render it a viable alternative for the synthesis of α,β-unsaturated ketones.
Yu, Meng,Li, Guotao,Wang, Shaozhong,Zhang, Liming
p. 871 - 875
(2008/03/27)

Pd-H from Pd/C and triethylamine: Implications in palladium catalysed reactions involving amines
The palladium hydride-iminium complex generated from Pd/C and triethylamine catalyses the isomerisation of allylic alcohols into carbonyl compounds, and Pd/C catalyses the conjugate reduction of activated double bonds using triethylamine as the source of the two newly incorporated hydrogen atoms via the same complex.
Coquerel, Yoann,Brémond, Paul,Rodriguez, Jean
p. 4805 - 4808
(2008/03/12)

Formation of nickeladihydropyran by oxidative addition of cyclopropyl ketone. Key intermediate in nickel-catalyzed cycloaddition
Cyclopropyl phenyl ketone underwent oxidative addition to Ni(PCy3) generated from Ni(cod)2 and PCy3 to give a nickeladihydropyran, which is a key intermediate for the Ni(0)-catalyzed homo- or heterocycloaddition to give cyclopentane compounds having two carbonyl substituents at the 1,3-position. Copyright
Ogoshi, Sensuke,Nagata, Midue,Kurosawa, Hideo
p. 5350 - 5351
(2007/10/03)

Microwave-assisted one-pot synthesis of 1-indanones from arenes and α,β-unsaturated acyl chlorides
A series of 1-indanones were synthesized in good yields via tandem Friedel-Crafts acylation and Nazarov cyclization of arenes and α,β-unsaturated acyl chlorides in the presence of aluminum chloride under microwave irradiation.
Yin, Wei,Ma, Yuan,Xu, Jiaxi,Zhao, Yufen
p. 4312 - 4315
(2007/10/03)

Method for conversion of terminal alkenes to aldehydes using ruthenium(IV) porphyrin catalysts
Aldehydes were obtained in excellent yields from ruthenium-porphyrin-catalyzed oxidation of various terminal alkenes with 2,6-dichloropyridine N-oxide under mild conditions. The aldehydes generated from these ruthenium-catalyzed alkene oxidation reactions can be used in-situ for olefination reactions with ethyl diazoacetate in the presence of PPh3, leading to one-pot diazoacetate olefination starting from alkenes.
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(2008/06/13)

Stereoselective synthesis of furans by the Pd-catalyzed Oshima-Utimoto reaction
(Chemical Equation Presented) The Pd-catalyzed coupling of acyclic allylic alcohols with vinyl ethers was examined and found to proceed with 2.5-10 mol % of catalyst and to provide cyclic acetals with good stereoselection. The reaction is tolerant of a number of functional groups and can be used to generate quaternary centers in a stereoselective fashion.
Evans, Michael A.,Morken, James P.
p. 3367 - 3370
(2007/10/03)

Synthesis of selenoxides by oxidation of selenides with superoxide radical anions and 2-nitrobenzenesulfonyl chloride
Alkyl phenyl selenoxides were produced in excellent yields by oxidation of the corresponding selenides with 2-nitrobenzenesulfonyl chloride and potassium superoxide in dry acetonitrile at -15°C.
Tiecco, Marcello,Testaferri, Lorenzo,Temperini, Andrea,Terlizzi, Raffaella,Bagnoli, Luana,Marini, Francesca,Santi, Claudio
p. 5165 - 5168
(2007/10/03)

Odorless diphenyl diselenide and disulfide: Syntheses and applications
Bis[4-(trimethylsilyl)phenyl]diselenide (3) and bis[4-(trimethylsilyl) phenyl]disulfide (31) are found to be odorless equivalents of the commonly used diphenyl diselenide and diphenyl disulfide, respectively. The diselenide 3 is shown to be useful in the preparation of odorless selenium(II) chloride 26 and selenium(IV) trichloride 28 that follow similar reactivity patterns to their phenyl derivatives and can be stored refrigerated under dry conditions. The corresponding selenium(II) bromide had to be prepared fresh from 3 before use. It is also shown that the trimethylsilyl group in the sulfide products can be protodesilylated quantitatively using TFA. Georg Thieme Verlag Stuttgart.
Patra, Pranab K.,Shanmugasundaram, Kandasamy,Matoba, Manabu,Nishide, Kiyoharu,Kajimoto, Tetsuya,Node, Manabu
p. 447 - 457
(2007/10/03)

A mild isomerization reaction for β,γ-unsaturated ketone to α,β-unsaturated ketone
A series of β,γ-unsaturated ketones were isomerized to their corresponding α,β-unsaturated ketones by the introduction of DABCO in iPrOH at room temperature. The endo-cyclic double bond (β,γ- position) on ketone was rearranged to exo-cyclic double bond (α,β-position) under the reaction conditions.
Lee, Adam Shih-Yuan,Lin, Mei-Chun,Wang, Shu-Huei,Lin, Li-Shin
p. 371 - 376
(2007/10/03)