- Novel synthesis of oxadiazinone and oxadiazepinone derivatives by ring expansion of diaziridinone
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Treatment of N, N'-di-tert-butyldiaziridinone with α-hydroxy ketones in the presence of a catalytic amount of BF3·OEt2 gave carbazate derivatives in excellent yields. Acid-catalyzed recyclization of these compounds easily proceeded to give oxadiazinone derivatives. The reaction was applicable to the synthesis of oxadiazepinone derivatives and also to one-pot process.
- Komatsu, Mitsuo,Sakai, Norio,Hakotani, Akira,Minakata, Satoshi,Ohshiro, Yoshiki
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Read Online
- Rearrangement of dypnones to 1,3,5-triarylbenzenes
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Rearrangement of dypnones to 1,3,5-triarylbenzenes is described. The reaction is proposed to involve an aldol-type self-condensation of dypnones, followed by an intramolecular [2 + 2] cycloaddition and a retro-[2 + 2] cycloaddition. The reaction goes smoothly under obviously milder conditions in comparison to the cyclotrimerization of acetophenones to 1,3,5-triarylbenzenes (10 mol % of TsOH, 80 °C versus 130-148 °C). This unexpected rearrangement would provide new possible considerations in dypnone-involved organic synthesis.
- Deng, Kai,Huai, Qi-Yong,Shen, Zhi-Lun,Li, Hui-Jing,Liu, Chen,Wu, Yan-Chao
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Read Online
- Chemoselective reduction of ?,￠-unsaturated carbonyl and carboxylic compounds by hydrogen iodide
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The selective reduction of ?,￠-unsaturated carbonyl compounds was achieved to produce saturated carbonyl compounds with aqueous HI solution. The introduction of an aryl group at an ? or ￠ position efficiently facilitated the reduction with good yield. The reaction was applicable to compounds bearing carboxylic acids and halogen atoms. Through the investigation of the reaction mechanism, it was found that Michael-type addition of iodide occurred to produce ￠-iodo compounds followed by the reduction of C-I bond via anionic and radical paths.
- Matsumoto, Shoji,Marumoto, Hayato,Akazome, Motohiro,Otani, Yasuhiko,Kaiho, Tatsuo
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p. 590 - 599
(2021/03/29)
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- Highly Enantioselective Iridium-Catalyzed Hydrogenation of Conjugated Trisubstituted Enones
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Asymmetric hydrogenation of conjugated enones is one of the most efficient and straightforward methods to prepare optically active ketones. In this study, chiral bidentate Ir-N,P complexes were utilized to access these scaffolds for ketones bearing the stereogenic center at both the α- and β-positions. Excellent enantiomeric excesses, of up to 99%, were obtained, accompanied with good to high isolated yields. Challenging dialkyl substituted substrates, which are difficult to hydrogenate with satisfactory chiral induction, were hydrogenated in a highly enantioselective fashion.
- Peters, Bram B. C.,Jongcharoenkamol, Jira,Krajangsri, Suppachai,Andersson, Pher G.
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p. 242 - 246
(2021/01/13)
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- HIGHLY ENANTIOSELECTIVE ACCESS TO CYCLIC BETA-AMINO ACIDS
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Disclosed herein is a method of forming a compound of formula I: wherein the substituents are defined in the specification. In particular, the compounds of formula I can be converted to amino acids bearing quaternary stereocenters with exceptional optical purities.
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Paragraph 0117; 0118
(2021/06/11)
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- Cobalt-Catalyzed Asymmetric 1,4-Hydroboration of Enones with HBpin
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Herein, a series of new 8-OIQ cobalt complexes were synthesized and used for cobalt-catalyzed chemo- and enantioselective 1,4-hydroboration of enones with HBpin to access chiral β,β-disubstituted ketones with good to excellent chemo- and enantioselectivties. This protocol is operationally simple and shows a broad substrate scope.
- Ren, Xiang,Lu, Zhan
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p. 8370 - 8374
(2021/11/01)
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- Preparation method of 1, 3-diphenyl-2-butene-1-ketone O-n-butyl oxime
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The invention relates to a preparation method of 1, 3-diphenyl-2-butene-1-ketone O-n-butyl oxime, and belongs to the technical field of organic synthesis. The method comprises the steps of by taking acetophenone as an initial raw material, dropwise adding thionyl chloride, carrying out solvent-free reaction under the catalysis of thionyl chloride, quenching, washing, extracting, and carrying out reduced pressure distillation to obtain purified 1, 3-diphenyl-2-butene-1-ketone; and sequentially adding hydroxylamine hydrochloride, potassium hydroxide, n-butyl bromide, ethanol and water into the obtained 1, 3-diphenyl-2-butene-1-ketone crude product, reacting at room temperature, and desolventizing the obtained product under reduced pressure to obtain the 1, 3-diphenyl-2-butene-1-ketone O-n-butyl oxime. By adopting the method disclosed by the invention, the 1, 3-diphenyl-2-butene-1-ketone O-n-butyl oxime can be prepared under conventional conditions, the intermediate does not need to be separated and purified, the operation is safe and simple, and the energy is saved. The method has the advantages of cheap initial raw materials and reduction of the production cost. The method is simple in process, low in energy consumption, convenient to operate and suitable for industrial large-scale production.
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Paragraph 0022-0024
(2021/06/23)
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- Visible Light Mediated Photocatalytic N-Radical Cascade Reactivity of O,δ-Unsaturated N-Arylsulfonylhydrazones: A General Approach to Structurally Diverse Tetrahydropyridazines
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Tetrahydropyridazines are of particular interest for their versatility as intermediates in organic synthesis and display pharmacological activity in several domains. Here, we describe the photocatalytic synthesis of different tetrahydropyridazines starting from O,δ-unsaturated N-arylsulfonylhydrazones. Simple structural changes of substrates result into three different pathways beginning from a common N-hydrazonyl radical, which evolves through a domino carboamination/dearomatization, a HAT process, or a photoinduced radical Smiles rearrangement to afford diverse tetrahydropyridazines. All reactions are carried out in very mild conditions, and the quite inexpensive [Ru(bpy)3]Cl2 is used as the catalyst. Preliminary mechanism studies are presented, among them luminescence and electrochemical characterization of the involved species. Computational studies allow to rationalize the mechanism in accord with the experimental findings.
- Azzi, Emanuele,Ghigo, Giovanni,Parisotto, Stefano,Pellegrino, Francesco,Priola, Emanuele,Renzi, Polyssena,Deagostino, Annamaria
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p. 3300 - 3323
(2021/02/16)
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- Asymmetric Alkoxy- and Hydroxy-Carbonylations of Functionalized Alkenes Assisted by β-Carbonyl Groups
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As a fundamental type of carbonylation reaction, the alkoxy- and hydroxy-carbonylation of unsaturated hydrocarbons constitutes one of the most important industrial applications of homogeneous catalysis. However, owing to the difficulties in controlling multi-selectivities for asymmetric hydrocarbonylation of alkenes, this reaction is typically limited to vinylarenes and analogues. In this work, a highly efficient asymmetric alkoxy- and hydroxy-carbonylation of β-carbonyl functionalized alkenes was developed, providing practical and easy access to various densely functionalized chiral molecules with high optical purity from broadly available alkenes, CO, and nucleophiles (>90 examples, 84–99 % ee). This protocol features mild reaction conditions and a broad substrate scope, and the products can be readily transformed into a diverse array of chiral heterocycles. Control experiments revealed the key role of the β-carbonyl group in determining the enantioselectivity and promoting the activity, which facilitates chiral induction by coordination to the transition metal as rationalized by DFT calculations. The strategy of utilizing an innate functional group as the directing group on the alkene substrate might find further applications in catalytic asymmetric hydrocarbonylation reactions.
- Dong, Kaiwu,Ji, Xiaolei,Ren, Xinyi,Shen, Chaoren,Tang, Lin,Tian, Xinxin,Wang, Zhen
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p. 17693 - 17700
(2021/07/10)
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- Alcohol Dehydrogenases and N-Heterocyclic Carbene Gold(I) Catalysts: Design of a Chemoenzymatic Cascade towards Optically Active β,β-Disubstituted Allylic Alcohols
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The combination of gold(I) and enzyme catalysis is used in a two-step approach, including Meyer–Schuster rearrangement of a series of readily available propargylic alcohols followed by stereoselective bioreduction of the corresponding allylic ketone intermediates, to provide optically pure β,β-disubstituted allylic alcohols. This cascade involves a gold N-heterocyclic carbene and an enzyme, demonstrating the compatibility of both catalyst types in aqueous medium under mild reaction conditions. The combination of [1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene][bis(trifluoromethanesulfonyl)-imide]gold(I) (IPrAuNTf2) and a selective alcohol dehydrogenase (ADH-A from Rhodococcus ruber, KRED-P1-A12 or KRED-P3-G09) led to the synthesis of a series of optically active (E)-4-arylpent-3-en-2-ols in good yields (65–86 %). The approach was also extended to various 2-hetarylpent-3-yn-2-ol, hexynol, and butynol derivatives. The use of alcohol dehydrogenases of opposite selectivity led to the production of both allyl alcohol enantiomers (93->99 % ee) for a broad panel of substrates.
- González-Granda, Sergio,Lavandera, Iván,Gotor-Fernández, Vicente
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p. 13945 - 13951
(2021/04/22)
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- A Bifunctional Copper Catalyst Enables Ester Reduction with H2: Expanding the Reactivity Space of Nucleophilic Copper Hydrides
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Employing a bifunctional catalyst based on a copper(I)/NHC complex and a guanidine organocatalyst, catalytic ester reductions to alcohols with H2 as terminal reducing agent are facilitated. The approach taken here enables the simultaneous activation of esters through hydrogen bonding and formation of nucleophilic copper(I) hydrides from H2, resulting in a catalytic hydride transfer to esters. The reduction step is further facilitated by a proton shuttle mediated by the guanidinium subunit. This bifunctional approach to ester reductions for the first time shifts the reactivity of generally considered "soft"copper(I) hydrides to previously unreactive "hard"ester electrophiles and paves the way for a replacement of stoichiometric reducing agents by a catalyst and H2.
- Kaicharla, Trinadh,Ngoc, Trung Tran,Teichert, Johannes F.,Tzaras, Dimitrios-Ioannis,Zimmermann, Birte M.
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supporting information
p. 16865 - 16873
(2021/10/20)
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- Catalytic Asymmetric Transfer Hydrogenation of trans-Chalcone Derivatives Using BINOL-derived Boro-phosphates
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Chiral phosphoric-acid-catalyzed asymmetric reductions of trans-chalcones have been investigated in this work. A BINOL-derived boro-phosphate-catalyzed asymmetric transfer hydrogenation of the carbon-carbon double bond of trans-chalcone derivatives employing borane as a hydride source was realized. This methodology provides a convenient procedure to access chiral dihydrochalone derivatives in high yields and with high enantioselectivities under mild conditions.
- Na, Fei,Lopez, Susana S.,Beauseigneur, Alice,Hernandez, Lucas W.,Sun, Zhuoxin,Antilla, Jon C.
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p. 5953 - 5957
(2020/08/12)
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- Pd-catalyzed imine-directed intramolecular C–N bond formation through C(sp3)–H activation: An efficient approach to multisubstituted pyrroles
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An atom-economic approach to synthesize 1,2,4-trisubstituted pyrroles through palladium-catalyzed imine-directed intramolecular C(sp3)–H amination reaction has been developed. The imine group acts as a directing group as well as an intramolecular nucleophile for the first time in intramolecular C–N bonds formation reactions.
- Yu, Ting,Zhu, Qiang,Luo, Shuang
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supporting information
(2020/04/08)
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- Method for synthesizing polysubstituted alpha, beta unsaturated ketones
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The invention particularly relates to a method for synthesizing polysubstituted alpha, beta unsaturated ketones. The method comprises the following steps: 1, adding Ni(cod), an N-heterocyclic carbene ligand, Cs2CO3 and a beta, gamma unsaturated ketone into a non-polar aprotic organic solvent, and mixing to obtain a mixture; 2, adding the mixture obtained in the step 1 into a dried container, reacting for 10-40 hours at the reaction temperature of 120-180 DEG C, and cooling to room temperature after the reaction is finished, so as to obtain a crude product; 3, purifying. According to the method, cheap Ni(cod) is adopted as a catalyst, carbon-carbon bonds are activated by a transition metal, power is provided for the reaction through isomerization of double bonds, the synthesis methodis simple, the substrates are stable and cheap, the reaction is less limited by the substrate, and the substrates are wide in application range.
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Paragraph 0044-0048
(2020/03/06)
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- Bi(OTf)3 catalyzed synthesis of acyclic β-sulfanyl ketones via a tandem Meyer-Schuster rearrangement/conjugate addition reaction
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A new strategy to prepare acyclic β-carbonyl thioethers from propargyl alcohols and sulfur nucleophiles is reported. The investigation of the reaction substrates scope indicated that primary 3-aryl propargyl alcohols and thiols underwent the transformation smoothly. The reaction probably proceeded a Bi(OTf)3-catalyzed tandem Meyer-Schuster rearrangement of 3-aryl propargyl alcohol, followed by a thiol Michael conjugate addition of thiols to in situ generated α, β-unsaturated ketones. The method was 100% atom economic, high-yielding, and easy to handle, making it a valuable method for the construction of β-carbonyl sulfides.
- Wang, Yuan,Yin, Yan,Zhang, Qinglin,Pan, Wanyong,Guo, Huifeng,Pei, Keke
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p. 2030 - 2034
(2019/07/03)
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- Nickel-Catalyzed Chemoselective Asymmetric Hydrogenation of α,β -Unsaturated Ketoimines: An Efficient Approach to Chiral Allylic Amines
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An efficient synthetic route to chiral allylic amines has been developed by nickel/(S,S)-Ph-BPE complex catalyzed chemoselective asymmetric hydrogenation of α,β-unsaturated ketoimines. Varieties of α,β-unsaturated ketoimines have been well tolerated in this transformation to give chiral allylic amines with high yields and excellent ee values (up to 99% yield, up to 99% ee). A gram-scale reaction with 0.2 mol % catalyst loading has also been achieved.
- Zhao, Xiang,Zhang, Feng,Liu, Kai,Zhang, Xumu,Lv, Hui
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supporting information
p. 8966 - 8969
(2019/11/11)
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- Access to Cyclic β-Amino Acids by Amine-Catalyzed Enantioselective Addition of the γ-Carbon Atoms of α,β-Unsaturated Imines to Enals
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Disclosed herein is a new catalytic approach for an efficient access to cyclic β-amino acids widely found in bioactive small molecules and peptidic foldamers. Our method involves addition of the remote γ-carbon atoms of α,β-unsaturated imines to enals by iminium organic catalysis. This highly chemo- and stereo-selective reaction affords cyclic β-amino aldehydes that can be converted to amino acids bearing quaternary stereocenters with exceptional optical purities. Our study demonstrates the unique power of organic catalytic remote carbon reactions in rapid synthesis of functional molecules.
- Luo, Guoyong,Huang, Zhijian,Zhuo, Shitian,Mou, Chengli,Wu, Jian,Jin, Zhichao,Chi, Yonggui Robin
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supporting information
p. 17189 - 17193
(2019/11/13)
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- Acylation of Alkenes with the Aid of AlCl3 and 2,6-Dibromopyridine
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Friedel-Crafts-type acylation of alkenes with acyl chlorides has been successfully conducted with a wide substrate scope by the combined use of AlCl3 and 2,6-dibromopyridine. Trisubstituted alkenes afford allylketones or vinylketones depending on the presence or absence of hydrogen atom(s) at the β-position to the acylation site, while monosubstituted alkenes exclusively afford vinylketones.
- Tanaka, Shinya,Kunisawa, Tsukasa,Yoshii, Yuji,Hattori, Tetsutaro
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supporting information
p. 8509 - 8513
(2019/11/03)
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- Chiral 1,3,2-Diazaphospholenes as Catalytic Molecular Hydrides for Enantioselective Conjugate Reductions
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Secondary 1,3,2-diazaphospholenes have a polarized P?H bond and are emerging as molecular hydrides. Herein, a class of chiral, conformationally restricted methoxy-1,3,2-diazaphospholene catalysts is reported. We demonstrate their catalytic potential in asymmetric 1,4-reductions of α,β-unsaturated carbonyl derivatives, including enones, acyl pyrroles, and amides, which proceeded in enantioselectivities of up to 95.5:4.5 e.r.
- Miaskiewicz, Solène,Reed, John H.,Donets, Pavel A.,Oliveira, Caio C.,Cramer, Nicolai
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supporting information
p. 4039 - 4042
(2018/03/13)
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- Ketalization of ketones to 1,3-dioxolanes and concurring self-aldolization catalyzed by an amorphous, hydrophilic SiO2-SO3H catalyst under microwave irradiation
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The amorphous, mesoporous SiO2-SO3H catalyst with a surface area of 115 m2 g-1 and 1.32 mmol H+ per g was very efficient for the protonation of ketones on a 10percent (m/m) basis, and the catalyst-bound intermediates can be trapped by polyalcohols to produce ketals in high yields or suffer aldol condensations within minutes under low-power microwave irradiation. The same catalyst can easily reverse the ketalization reaction. Printed in Brazil-
- Barbosa, Sandro L.,Ottone, Myrlene,De Almeida, Mainara T.,Lage, Guilherme L.C.,Almeida, Melina A.R.,Nelson, David Lee,Dos Santos, Wallans T.P.,Clososki, Giuliano C.,Lopes, Norberto P.,Klein, Stanlei I.,Zanatta, Lucas D.
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p. 1663 - 1671
(2018/06/29)
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- C-Alkylation of N-alkylamides with styrenes in air and scale-up using a microwave flow reactor
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C-Alkylation of N-alkylamides with styrenes is reported, proceeding in ambient air/moisture to give arylbutanamides and pharmaceutically-relevant scaffolds in excellent mass balance. Various amide and styrene derivatives were tolerated, rapidly affording molecular complexity in a single step; thus highlighting the future utility of this transformation in the synthetic chemistry toolbox. Reaction scalability (up to 65 g h-1 product) was demonstrated using a Microwave Flow reactor, as the first example of a C-alkylation reaction using styrenes in continuous flow.
- Barham, Joshua P.,Tamaoki, Souma,Egami, Hiromichi,Ohneda, Noriyuki,Okamoto, Tadashi,Odajima, Hiromichi,Hamashima, Yoshitaka
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supporting information
p. 7568 - 7573
(2018/11/02)
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- Regio- and Stereoselective Nickel-Catalyzed Coupling of Boronic Acids with Allenoates
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The Ni(II)-catalyzed cross-coupling of arylboronic acids with allenoates is documented. The high regio- and stereoselectivity of the process enables a wide range of β-aryl β,γ-unsaturated esters to be prepared in good to excellent yields (up to 95%) and high E / Z -selectivity. Additionally, [3+2]-cascade sequence was observed when 2-formylphenylboronic acid was employed.
- Liu, Yang,Daka, Mario,Bandini, Marco
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p. 3187 - 3196
(2018/08/17)
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- Highly efficient synthesis of chiral aromatic ketones: Via Rh-catalyzed asymmetric hydrogenation of β,β-disubstituted enones
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A succinct and efficient protocol was developed for the synthesis of chiral aromatic ketones via asymmetric hydrogenation of β,β-disubstituted enones with rhodium catalysts based on chiral bisphosphine thiourea ligands. A series of substrates (17 examples) was smoothly catalyzed to afford the corresponding chiral aromatic ketones in high conversions (>99%) with excellent enantioselectivities (up to 96% ee).
- Zhang, Tao,Jiang, Jun,Yao, Lin,Geng, Huiling,Zhang, Xumu
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p. 9258 - 9261
(2017/08/22)
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- Base-promoted isomerization of CF3-containing allylic alcohols to the corresponding saturated ketones under metal-free conditions
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Following to the computational expectation, our previously reported intriguing 1,3-proton shift of 4,4,4-trifluorobut-2-yn-1-ols was successfully extended to the 4,4,4-trifluorobut-2-en-1-ol system under metal-free conditions to afford the corresponding saturated ketones in high to excellent chemical yields using such a convenient and easy-to-handle base as DBU at the toluene refluxing temperature, and utilization of the corresponding optically active substrates unambiguously demonstrated that this transformation proceeded in a highly stereoselective fashion.
- Hamada, Yoko,Kawasaki-Takasuka, Tomoko,Yamazaki, Takashi
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supporting information
p. 1507 - 1512
(2017/08/14)
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- Sulfated tungstate catalyzed synthesis of C3-symmetric 1,3,5-triaryl benzenes under solvent-free condition
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Sulfated tungstate catalyzed environmentally benign, simple, one pot, and solvent-free method has been developed for the synthesis of 1,3,5-triarylbenzenes via cyclic self-condensation of three molecules of aryl ketones. High yields, short reaction time, easy work-up procedure and recycling of the catalyst endorse advantage.
- Wagh, Ganesh D.,Akamanchi, Krishnacharya G.
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p. 3032 - 3036
(2017/07/17)
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- Dynamic Kinetic Resolution of Allylic Azides via Asymmetric Dihydroxylation
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The catalytic enantioselective preparation of densely functionalized amines is a fundamental synthetic challenge. To address this challenge, we report for the first time that the Winstein rearrangement can be enlisted as the racemization pathway in a dynamic kinetic resolution of allylic azides. Alkene functionalization by Sharpless dihydroxylation affords tertiary azides in excellent enantioselectivity (up to 99:1 er). This approach establishes the chirality of the tertiary azide, obviates the need to directly forge either a congested C-N or C-C bond at the new nitrogenous stereocenter, and establishes additional functionality. Several examples demonstrate further elaboration of this functionality.
- Ott, Amy A.,Goshey, Charles S.,Topczewski, Joseph J.
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supporting information
p. 7737 - 7740
(2017/06/21)
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- Nickel-Catalyzed Direct Synthesis of Aryl Olefins from Ketones and Organoboron Reagents under Neutral Conditions
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Nickel-catalyzed addition of arylboron reagents to ketones results in aryl olefins directly. The neutral condition allows acidic protons of alcohols, phenols, and malonates to be present, and fragile structures are also tolerated.
- Lei, Chuanhu,Yip, Yong Jie,Zhou, Jianrong Steve
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supporting information
p. 6086 - 6089
(2017/05/08)
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- Iridium(I) N-Heterocyclic Carbene (NHC)/Phosphine Catalysts for Mild and Chemoselective Hydrogenation Processes
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The directed chemoselective hydrogenation of olefins has been established by using iridium(I) catalysts, which feature a tuned NHC/phosphine ligand combination. This selective reduction process has been demonstrated in a wide array of solvents, including more environmentally acceptable media, also allowing further refinement of hydrogenation selectivity. The directed, chemoselective hydrogenation of olefins has been established by using iridium(I) catalysts, which feature a tuned NHC/phosphine ligand combination. This selective reduction process has been demonstrated in a wide array of solvents, including more environmentally acceptable media, also allowing further refinement of hydrogenation selectivity.
- Kerr, William J.,Mudd, Richard J.,Brown, Jack A.
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supporting information
p. 4738 - 4742
(2016/04/05)
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- Triazole acetyl gold(III) catalyzed Meyer-Schuster rearrangement of propargyl alcohols
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A new type triazole acetyl gold(III) was prepared and found to be an effective catalyst in Meyer-Schuster rearrangement of propargyl alcohols. The reactions proceeded well under much milder conditions to afford enones bearing a wide range of functional groups, thereby opening a new avenue for gold(III) catalysis. In addition, TriaAuCl2 catalyst was also effective on promotion of a-haloenones synthesis.
- Yang, Yongchun,Shen, Yanan,Wang, Xiaoli,Zhang, Yao,Wang, Dawei,Shi, Xiaodong
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supporting information
p. 2280 - 2282
(2016/05/10)
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- Bifunctional Ru(II) complex catalysed carbon-carbon bond formation: an eco-friendly hydrogen borrowing strategy
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The atom economical borrowing hydrogen methodology enables the use of alcohols as alkylating agents for selective C-C bond formation. A bifunctional 2-(2-pyridyl-2-ol)-1,10-phenanthroline (phenpy-OH) based Ru(ii) complex (2) was found to be a highly efficient catalyst for the one-pot β-alkylation of secondary alcohols with primary alcohols and double alkylation of cyclopentanol with different primary alcohols. Exploiting the metal-ligand cooperativity in complex 2, several aromatic, aliphatic and heteroatom substituted alcohols were selectively cross-coupled in high yields using significantly low catalyst loading (0.1 mol%). An outer-sphere mechanism is proposed for this system as exogenous PPh3 has no significant effect on the rate of the reaction. Notably, this is a rare one-pot strategy for β-alkylation of secondary alcohols using a bifunctional Ru(ii)-complex. Moreover, this atom-economical methodology displayed the highest cumulative turn over frequency (TOF) among all the reported transition metal complexes in cross coupling of alcohols.
- Chakrabarti, Kaushik,Paul, Bhaskar,Maji, Milan,Roy, Bivas Chandra,Shee, Sujan,Kundu, Sabuj
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supporting information
p. 10988 - 10997
(2016/12/06)
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- Iron-facilitated oxidative radical decarboxylative cross-coupling between α-oxocarboxylic acids and acrylic acids: An approach to α,β-unsaturated carbonyls
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The first Fe-facilitated decarboxylative cross-coupling reaction between α-oxocarboxylic acids and acrylic acids in aqueous solution has been developed. This transformation is characterized by its wide substrate scope and good functional group compatibility utilizing inexpensive and easily accessible reagents, thus providing an efficient and expeditious approach to an important class of α,β-unsaturated carbonyls frequently found in bioactive compounds. The synthetic potential of the coupled products is also demonstrated in subsequent functionalization reactions. Preliminary mechanism studies suggest that a free radical pathway is involved in this process: the generation of an acyl radical from α-oxocarboxylic acid via the excision of carbon dioxide followed by the addition of an acyl radical to the α-position of the double bond in acrylic acid then delivers the α,β-unsaturated carbonyl adduct through the extrusion of another carbon dioxide.
- Jiang, Qing,Jia, Jing,Xu, Bin,Zhao, An,Guo, Can-Cheng
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p. 3586 - 3596
(2015/04/22)
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- One-Pot Synthesis of β,β-Disubstituted α,β-Unsaturated Carbonyl Compounds
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TiCl4-promoted aldol reaction of ketones as aldol acceptors followed by elimination of the titanoxy group from the Ti-aldolates affords β,β-disubstituted α,β-unsaturated carbonyl compounds in a one-pot procedure. The use of additives, such as DMF, N,N,N′,N′-tetramethylethylenediamine, and pyridine, in the elimination step was found to be important.
- Sugiura, Masaharu,Ashikari, Yasuhiko,Nakajima, Makoto
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p. 8830 - 8835
(2015/09/15)
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- Synthesis of Acyl Alkenylindium Reagents and Their Application in the Synthesis of (Z)-α,β-Unsaturated Ketones via Palladium-Catalyzed Cross-Coupling Reaction
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A synthetic method for the preparation of acyl alkenylindium reagents was developed involving the hydroindation reaction of allenyl ketones with indium and indium chloride in methanol under mild conditions. Their synthetic applications were demonstrated from Pd-catalyzed cross-coupling reactions with aryl bromides and iodides and alkenyl and aryl triflates for the synthesis of (Z)-α,β-unsaturated ketones.
- Park, Youngchul,Min, Jiae,Eom, Dahan,Lee, Phil Ho
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supporting information
p. 3934 - 3937
(2015/08/19)
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- METHODS FOR PRODUCING CYCLIC AND ACYCLIC KETONES
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Provided herein are methods for producing cyclic and acyclic ketones from trimerization and dimerization of alkyl ketones, including for example methyl ketones. Such cyclic and acyclic ketones may be suitable for use as fuel and lubricant precursors, and may be hydrodeoxygenated to form their corresponding cycloalkanes and alkanes. Such cycloalkanes and alkanes may be suitable for use as fuels, including jet fuels, and lubricants.
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Paragraph 0203; 0204
(2015/12/08)
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- Highly enantioselective hydrogenation of steric hindrance enones catalyzed by Ru complexes with chiral diamine and achiral phosphane
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An asymmetric hydrogenation of sterically hindered β,β- disubstituted enones has been well-established by using a ruthenium complex composed of an achiral diphosphane and a chiral diamine as catalyst, wherein the carbonyl group was selectively hydrogenated to give a wide range of chiral allylic alcohols with high levels of enantioselectivity and complete chemoselectivity.
- Chen, Xiangning,Zhou, Han,Zhang, Kunyu,Li, Jiawen,Huang, Hanmin
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p. 3912 - 3915
(2014/08/18)
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- Synthesis and antimalarial activity of 3,3-spiroanellated 5,6-disubstituted 1,2,4-trioxanes
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Novel 3,3-spiroanellated 5-aryl, 6-arylvinyl-substituted 1,2,4-trioxanes 19-34 have been synthesized and appraised for their antimalarial activity against multidrug-resistant Plasmodium yoelii nigeriensis in Swiss mice by oral route at doses ranging from 96 mg/kg × 4 days to 24 mg/kg × 4 days. The most active compound of the series (compound 25) provided 100% protection at 24 mg/kg × 4 days, and other 1,2,4-trioxanes 22, 26, 27, and 30 also showed promising activity. In this model, β-arteether provided 100 and 20% protection at 48 mg/kg × 4 days and 24 mg/kg × 4 days, respectively, by oral route. Compound 25 displayed a similar in vitro pharmacokinetic profile to that of reference drug β-arteether. The activity results demonstrated the importance of an aryl moiety at the C-5 position on the 1,2,4-trioxane pharmacophore.
- Maurya, Ranjani,Soni, Awakash,Anand, Devireddy,Ravi, Makthala,Raju, Kanumuri S.R.,Taneja, Isha,Naikade, Niraj K.,Puri,Wahajuddin,Kanojiya, Sanjeev,Yadav, Prem P.
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supporting information
p. 165 - 169
(2013/03/29)
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- Molecular and Merrifield supported chiral diamines for enantioselective addition of ZnR2 (R = Me, Et) to ketones
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Chiral 1,2-ethylenediamines have been previously reported as active catalysts in the enantioselective addition reactions of ZnR2 to either methyl- or trifluoromethyl-ketones. Subtle changes in the molecular structure of different catalysts are described herein and lead to a dramatic effect in their catalytic activity. From these findings, we demonstrate the selective reactivity of the ligands used in the addition of ZnR2 (R = Me, Et) to methyl- and trifluoromethyl-ketones offering an enantioselective access either to chiral non-fluorinated alcohols or to chiral fluorinated tertiary alcohols. Considering the importance of the chiral trifluoromethyl carbinol fragment in several biologically active compounds, we have extended the scope of the addition reaction of ZnEt2 to several trifluoromethylketones catalyzed by (R,R)-1,2-diphenylethylenediamine derivatives. This work explores a homogeneous approach that provides excellent yields and very high ee and the use of a heterogenized tail-tied ligand affording moderate ee, high yields and allowing an easier handling and recycling.
- Calvillo-Barahona, Mercedes,Cordovilla, Carlos,Genov, Miroslav N.,Martinez-Ilarduya, Jesus M.,Espinet, Pablo
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p. 14576 - 14582
(2013/10/08)
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- Condensation of adamantanone with methylene-active compounds
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A convenient method was developed for the preparation of potentially bioactive substances with 2-adamantyl radical and of intermediates for their synthesis. Condensation of adamantanone with methylene-active compounds was performed, and the reaction features were determined.
- Popov,Mokhov,Tankabekyan
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p. 404 - 409
(2013/07/04)
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- Copper-catalyzed aldol-type addition of ketones to aromatic nitriles: A simple approach to enaminone synthesis
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An efficient method for the synthesis of enaminones is described. The aldol-type addition of ketones to aromatic nitriles proceeded smoothly in the presence of a simple copper catalyst system (CuI-2,2′-bipyridine-NaO tBu) in N,N-dimethylformamide. Enaminones in satisfactory to excellent yields were produced using this technique. The Royal Society of Chemistry 2013.
- Yu, Xiaoqiang,Wang, Longxiang,Feng, Xiujuan,Bao, Ming,Yamamoto, Yoshinori
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p. 2885 - 2887
(2013/04/24)
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- Pd-catalyzed asymmetric hydrogenation of C=C bond of α,β- unsaturated ketones
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Homogenous palladium-catalyzed asymmetric hydrogenation of C=C double bond of ,-unsaturated ketones has been -developed by using palladium(II) trifluoroacetate/(S)-7,7-bis-[di(4-methoxyphenyl]phosphino)-1,1-spirobiindane complex [Pd(OCOCF3)2-(S)-An-SDP] as the catalyst under ambient hydrogen pressure and room temperature with up to 89% ee. Georg Thieme Verlag Stuttgart · New York.
- Wang, Duo-Sheng,Wang, Da-Wei,Zhou, Yong-Gui
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supporting information; experimental part
p. 947 - 950
(2011/06/17)
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- Iron-catalyzed asymmetric epoxidation of β,β-disubstituted enones
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The combination of Fe(OTf)2 and novel phenanthroline ligands enables the catalytic asymmetric epoxidation of acyclic β,β- disubstituted enones, which have been a heretofore inaccessible substrate class. The reaction provides highly enantioenriched α,β-epoxyketones (up to 92% ee) that can be further converted to functionalized β-ketoaldehydes with an all-carbon quaternary center.
- Nishikawa, Yasuhiro,Yamamoto, Hisashi
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p. 8432 - 8435
(2011/07/29)
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- Ionic liquid catalysed synthesis of β-hydroxy ketones
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Different acidic ionic liquids (ILs; namely, 1-methylimidazolium tetrafluoroborate, 1-methylimidazolium trifluoroacetate, N-methyl-2-pyrrolidone hydrogen sulfate, N,N,N-trioctyl-n-butanesulfonic acid ammonium hydrogen sulfate, 1-methyl-3-(3-sulfobutyl)imidazolium hydrogen sulfate) and basic ILs (namely, 1,1,3,3-tetramethylguanidinium lactate and choline hydroxide) were tested as catalysts for the aldol reaction. The choline hydroxide catalysed reaction gave high yield (94.3%) and selectivity of the 4-hydroxy-4-phenylbutan- 2-one after a short reaction time (15min) at 0°C. This article demonstrates the potential of choline hydroxide, which is a derivative of choline and a naturally occurring water-soluble essential nutrient, as a highly active and selective green catalyst.
- Karmee, Sanjib Kumar,Hanefeld, Ulf
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experimental part
p. 1118 - 1123
(2012/04/17)
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- Direct synthesis of carbon-templating mesoporous ZSM-5 using microwave heating
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Carbon-templated mesoporous ZSM-5 zeolites were synthesized directly avoiding a drying process. Carbon nanoparticles were simply mixed into synthesis precursor of ZSM-5 and hydrothermally treated by microwave irradiation. The amount of mesopores formed inside the ZSM-5 single crystals was controllable by adjusting the amount of carbon used. For comparison, mesoporous ZSM-5 zeolites have also been synthesized under hydrothermal conditions. The influence of microwave irradiation on mesoporous ZSM-5 materials was thoroughly investigated by using nitrogen adsorption/desorption studies and 27Al MAS NMR. The nature of acid sites both in the micropores (internal) and on the surface of mesopores (external) was investigated by in situ FTIR spectroscopy using pyridine (Py) and 2′,6′-di-tert-butylpyridine (DTBPy) as a probe molecules. Mesoporous ZSM-5 prepared by microwave synthesis showed higher catalytic activity in the bulky molecular reaction of 2′,4′- dimethoxyacetophenone (2′,4′-DMAP) with 4-methoxybenzaldehyde as a model reaction in comparison with the results obtained over hydrothermally prepared ZSM-5. The further catalytic behavior has been studied in condensation reaction and cracking of substituted benzene.
- Koo, Jeong-Boon,Jiang, Nanzhe,Saravanamurugan, Shunmugavel,Bejblova, Martina,Musilova, Zuzana,Cejka, Jiri,Park, Sang-Eon
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experimental part
p. 327 - 334
(2011/02/27)
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- Catalytic enantioselective construction of β-quaternary carbons via a conjugate addition of cyanide to β,β-disubstituted α,β-unsaturated carbonyl compounds
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The first general catalytic enantioselective conjugate addition of cyanide to β, β-disubstituted α,β-unsaturated ketones and N-acylpyrroles was developed using a strontium catalyst derived from Sr(O iPr)2 and new chiral ligand 5. The reaction exhibited excellent enantioselectivity and a wide substrate scope using 0.5-10 mol % catalyst. 1,4-Adducts containing β-quaternary carbons were exclusively produced over 1,2-adducts. ESI-MS analysis of the strontium catalyst indicated that the active catalyst was a trimetallic Sr/5 = 3:5 complex. The exclusive 1,4-selectivity was partly due to the ability of the strontium complex to promote both a retro-cyanation reaction from the 1,2-adducts and highly enantioselective conjugate cyanation.
- Tanaka, Yuta,Kanai, Motomu,Shibasaki, Masakatsu
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supporting information; experimental part
p. 8862 - 8863
(2010/08/21)
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- Catalytic enantioselective synthesis of sterically demanding alcohols using di(2°-alkyl)zinc prepared by the refined Charette's method
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A highly practical, catalytic enantioselective 2°-alkyl addition to aldehydes and ketones was developed. Chiral phosphoramide ligand (1) with salt-free and solvent-free di(2°-alkyl)zinc reagents prepared from (2°-alkyl)MgCl was essential. The Royal Society of Chemistry 2010.
- Hatano, Manabu,Mizuno, Tomokazu,Ishihara, Kazuaki
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supporting information; experimental part
p. 5443 - 5445
(2010/10/04)
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- A concise synthesis of (S)-(+)-ginnol based on catalytic enantioselective addition of commercially unavailable Di(n -alkyl)zinc to aldehydes and ketones
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Catalytic, enantioselective n-alkyl addition of commercially unavailable di(n-alkyl)zinc reagents, which were prepared by a refined version of Charettes procedure with Grignard reagents, to aldehydes and ketones was developed. To minimize the side reactions in the catalysis by chiral phosphoramide ligand (1) or 3,3-diphosphoryl-BINOL ligand (2), a preparation of di(n-alkyl)zinc reagents with a 1:2.5:1.6 molar ratio of ZnClNaOMe/RMgCl under solvent-free conditions was essential. Optically pure (S)-(+)-ginnol (17) was readily synthesized in one step for the first time by the catalytic enantioselective n-nonylation of icosanal. Georg Thieme Verlag.
- Hatano, Manabu,Mizuno, Tomokazu,Ishihara, Kazuaki
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scheme or table
p. 2024 - 2028
(2010/10/04)
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- Highly chemo- And enantioselective hydrogenation of linear α,β-unsaturated ketones
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A study was conducted to report the synthesis of sulfoximine-derived P,N-ligands and their applications in indium-catalyzed asymmetric hydrogenation reactions. Investigations were conducted using linear β,β- disubstituted 1,3-diphenyl-2-butenone as model substrate and iridium, having a ketonic phenyl group and two alkyl substituents at the olefinic β-positions. Methyl ketone with β-methyl and β-phenyl substituent was also applied in the investigations.
- Lu, Sheng-Mei,Bolm, Carsten
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supporting information; experimental part
p. 7513 - 7516
(2009/09/06)
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- Increased conversion to 2,4,6-triarylpyrylium salt: Aldol cyclotrimerization of acetophenone in BMImPF6 ionic liquid
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Substituted acetophenone 1 in BMImPF6 ionic liquid, heated at 120 °C for 24 h, produces β-methylchalcone 2, triarylbenzene 3, and triarylpyrylium salt 4. BMImPF6 catalyzes the self-aldol condensation of 1, whose cyclotrimerization gi
- Chuang, Po-Neng,Wu, Tsao-Dong,Liu, Ling-Kang
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experimental part
p. 512 - 516
(2009/05/11)
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- Synthesis of diketones and ω-hydroxy ketones from methyl ketones and α,ω-diols by an [IrCl(eod)]2/PPh3/KOH system
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ω-Hydroxy ketones and diketones, which are important starting materials for the synthesis of cycloalkanones and heterocyclic compounds, were prepared by the one-step reaction of methyl ketones with α,ω-diols under the influence of an iridium complex and a base. The selectivity of ω-hydroxy ketones and diketones could be controlled by varying the starting ratio of methyl ketones to α,ωdiols. For example, reaction using acetophenone (5 equiv) with respect to 1,6-hexanediol (1 equiv) in the presence of [IrCl(cod)]2, PPh3, and KOH without solvent gave 1,10-diphenyl-1,10-decane-dione in almost quantitative yield, while reaction using acetophenone (1 equiv) to 1,6-hexanediol (4 equiv) led to 8-hy-droxy-l-phenyl-l-octanone in 92% yield. This methodology was successfully extended to the reaction of arylacetonitriles with α.ω-odiols leading to diaryldinitriles.
- Maeda, Kensaku,Obora, Yasushi,Sakaguchi, Satoshi,Ishii, Yasutaka
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experimental part
p. 689 - 696
(2009/04/07)
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- Ruthenium-catalyzed 1,4-addition of organoboronic acids to α,β-unsaturated ketones
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A ruthenium-catalyzed 1,4-addition of organoboronic acids to α,β-unsaturated ketones has been developed. The use of 2-(di-tert-butylphosphino)biphenyl as the ligand in combination with [RuCl 2(p-cymene)]2 complex catalyzes these reactions to selectively give 1,4-adducts in good yield by effectively suppressing Heck-type and reduced products. Copyright
- Shintani, Ryo,Hayashi, Tamio
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p. 724 - 725
(2008/12/21)
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- Asymmetric conjugate reduction of α,β-unsaturated ketones and esters with chiral rhodium(2,6-bisoxazolinylphenyl) catalysts
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New asymmetric conjugate reduction of β,β-disubstituted α,β-unsaturated ketones and esters was accomplished with alkoxylhydrosilanes in the presence of chiral rhodium(2,6-bisoxazolinylphenyl) complexes in high yields and high enantioselectivity. (E)-4-Phenyl-3-penten-2- one and (E)-4-phenyl-4-isopropyl-3-penten-2-one were readily reduced at 60°C in 95% ee and 98 % ee, respectively, by 1 mol % of catalyst loading. (EtO) 2MeSiH proved to be the best hydrogen donor of choice. tert-Butyl (E)-β-methylcinnamate and β-isopropylcinnamate could also be reduced to the corresponding dihydrocinnamate derivatives up to 98% ee.
- Kanazawa, Yoshinori,Tsuchiya, Yasunori,Kobayashi, Kazuki,Shiomi, Takushi,Itoh, Jun-Ichi,Kikuchi, Makoto,Yamamoto, Yoshihiko,Nishiyama, Hisao
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