- Nickel(II) complexes bearing phosphinoaryl oxazoline ligands as pro- catalysts for Grignard cross-coupling
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Ni(II) complexes bearing chiral phosphinoaryl oxazoline ligands are pro- catalysts for cross-coupling of Z-styryl bromide with 1-phenethyl magnesium chloride. Under suitable conditions, there is a dynamic kinetic resolution resulting in moderate enantioselectivity. The nature of the substituent at the stereogenic centre of the oxazoline ligand affects catalysis in two distinct ways: smaller substituents lead to improved rates and selectivities whilst polar substituents reverse the sense of asymmetric induction. The solid state structure of one phosphinoaryl oxazoline Ni(II) pro-catalyst was determined by single crystal x-ray diffraction.
- Lloyd-Jones, Guy C.,Butts, Craig P.
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- HI gas as a reagent for α-alkylation reaction with two ketone molecules
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To develop the utilization of HI as an 'old but new' reagent, we found that the reaction of acetophenone analogues with HI gas proceeded to give an α-alkylated product, which is derived from the two ketone molecules. It was possible to conduct the reaction in solvent-free and various organic solvents under anhydrous conditions. From the investigation on the reaction mechanism, we proposed that HI acts as an acid and a reducing agent.
- Matsumoto, Shoji,Koitabashi, Seigo,Otani, Yasuhiko,Akazome, Motohiro
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- Synthesis of chiral supramolecular bisphosphinite palladacycles through hydrogen transfer-promoted self-assembly process
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P-Chiral secondary phosphine oxides react with Pd2(dba)3 in an acidic medium to provide chiral supramolecular bisphosphinite palladacycles through a H-transfer-based self-assembly process prior to SPO-promoted oxidative addition of an acid to a Pd(0) centre. The one-pot methodology allows variations of the X-type ligand as desired. Eight complexes have been characterised by X-ray diffraction.
- Vasseur, Alexandre,Membrat, Romain,Palpacelli, Davide,Giorgi, Michel,Nuel, Didier,Giordano, Laurent,Martinez, Alexandre
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- Enantioselective conjugate addition of organocuprate using a chiral amidophosphine ligand
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Based on the concept of a metal differentiating coordination, a new chiral amidophosphine ligand 2 was designed, synthesized, and applied in an enantioselective conjugate addition of lithium dimethylcuprate to chalcone providing the corresponding adduct i
- Kanai, Motomu,Koga, Kenji,Tomioka, Kiyoshi
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- HYDRIDIC REDUCTIONS OF CARBON MONOXIDE TO HYDROCARBONS ON IRON COMPLEXES
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Treatment of Cp2Fe(CO)4 with LiAlH4 produces CH4, C2H4, C2H6, C3H6, C3H8, C4H8 and C4H10.The exact ratio depends on the amount of LiAlH4 used and on the length of reaction.All reactions were carried out with LiAlD4, confirming that CO is reduced with LiAlH4 as the only hydrogen source.By preparing potential intermediates (CH3FeCp(CO)2, C2H5FeCp(CO)2 and CH3C(O)FeCp(CO)2) and treating them with LiAlD4, we have found evidence for a CO insertion mechanism in chain propagation.Other hydridic reagents were used, the reactivity for the reduction of CO decreases LiAlH4 > NaBH4 > LiEt3BH.
- Wong, Andrew,Atwood, Jim D.
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- Arenethgiolatocopper(I) Complexes as Homogeneous Catalysts for Michael Addition Reactions
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Arenethiolatocopper(I) complexes are shown to be efficient homogeneous catalysts in Michael addition reaction of several Grignard reagents to acyclic enones; the addition products are formed with excellent chemoselectivity ( >99percent ) and good enantios
- Klaveren, Mayra van,Lambert, Francois,Eijkelkamp, Desiree J. F. M.,Grove, David M.,Koten, Gerard van
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- Rational Design of New Dihydrobenzooxophosphole-Based Lewis Base Organocatalysts
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A series of new dihydrobenzooxophosphole-based Lewis base organocatalysts were designed and synthesized. They are shown to be effective in trichlorosilane-mediated stereoselective conjugate reductions of C=C bonds. DFT calculations reveal that the strong
- Busacca, Carl A.,Haddad, Nizar,Han, Zhengxu S.,Kozlowski, Marisa C.,Qu, Bo,Saha, Anjan,Samankumara, Lalith P.,Schumer, Mac G.,Senanayake, Chris H.,Song, Jinghua J.,Yee, Nathan K.
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- Iron-catalysed regio- And stereoselective head-to-tail dimerisation of styrenes
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Cationic iron salts and complexes catalyse the head-to-tail dimerisation of styrene derivatives to form the corresponding dimers with good to excellent yields and stereoselectivities. In particular, the use of a phosphine-iron(III) complex allows the recovery and reuse of the catalyst. The counteranion plays an important role in both the activity and selectivity. These catalysts constitute an alternative to those based on toxic and expensive late-transition metals.
- Cabrero-Antonino, Jose R.,Leyva-Perez, Antonio,Corma, Avelino
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- Aldol Reactions Promoted by Diethylzinc; the X-ray Crystal Structure and Stereochemistry of Dypnopinacol.
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Diethylzinc reacted with acetophenone to give the aldol dimer, 1,3-diphenyl-2-butene-1-one together with small amounts of dypnopinacol 1-(2-hydroxy-6-methyl-2,4,6-triphenylcyclohex-3-enyl)-1-phenylmethanone.The structure of dypnopinacol was established in an X-ray diffration study.Key Words: Aldol; Diethylzinc, Conjugate reduction; Dypnopinacol
- Chaloner, Penny A.,Hitchcock, Peter B.,Langadianou, Eugenia,Readey, Michael J.
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- First example of an enantiospecific sp3-sp2 Stille coupling of a chiral allylstannane with aryl halides
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A chiral allylic stannane, easily accessible via an enantiotopos differentiating deprotonation of a 1-phenyl-1-alkenyl-carbamate, is coupled with different aryl halides. In this enantiospecific Stille reaction a η3-bound palladium species is as
- Kalkofen, Rainer,Hoppe, Dieter
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- Synthesis of 1,3-diaryl butanones from acetophenones via a tandem reaction
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A tandem reaction for the simple construction of 1,3-diaryl butanones from acetophenones was developed. Anhydrous HI was generated in situ by the promotion of the [Rh]- complex with molecular hydrogen and iodine. The acetophenones undergo aldol reactions
- Li, Sida,Laishram, Ronibala Devi,Shen, Guoli,Zhang, Xuexin,Yang, Yong,Ni, Jianxiao,Zhan, Yong,Zhou, Yongyun,Fan, Baomin
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- Chiral lithiothiophenes as non-transferable ligands in organocuprate conjugate addition reactions
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Non-transferable carbon bound homochiral ligands have been developed for the asymmetric transfer of an alkyl or an aryl group to a prochiral α,β-unsaturated enone with copper reagents. These ligands are based on thiophene and chiral amino alcohols derived from L-proline and ephedrine.
- Ogle, Craig A.,Human, Jason B.
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- Electron deficient dienes. 2. One step synthesis of a coumarin-fused electron deficient diene and its inverse electron demand Diels-Alder reactions with enamines
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A coumarin-fused electron deficient diene was prepared by the base- induced reaction of dimethyl glutaconate and salicaldehyde. Its inverse electron demand Diels-Alder reactions with enamines give, after in situ elimination and dehydrogenation, benzocoumarins.
- Bodwell, Graham J.,Pi, Zulan,Pottie, Ian R.
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- Arylboronic Acid Catalyzed Dehydrative Mono-/Dialkylation Reactions of β-Ketoacids and Alcohols
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The dehydrative mono-/dialkylation reactions of alcohols and β-ketoacids were realized under arylboronic acid catalysis, furnishing a series of β-aryl ketones and β-ketoesters in yields of 15–99%, with CO2 and H2O being the byproduct
- Feng, Juhua,Hu, Haipeng,Ni, Hailiang,Qiu, Yuqian,Wang, Cuilin,Wang, Guangtu,Wang, Hanguang,Wang, Wei,Wu, Xin,Yue, Guizhou,Zou, Ping
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supporting information
p. 832 - 836
(2022/02/05)
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- 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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- Indene Derived Phosphorus-Thioether Ligands for the Ir-Catalyzed Asymmetric Hydrogenation of Olefins with Diverse Substitution Patterns and Different Functional Groups
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A family of phosphite/phosphinite-thioether ligands have been tested in the Ir-catalyzed asymmetric hydrogenation of a range of olefins (50 substrates in total). The presented ligands are synthesized in three steps from cheap indene and they are air-stable solids. Their modular architecture has been crucial to maximize the catalytic performance for each type of substrate. Improving most Ir-catalysts reported so far, this ligand family presents a broader substrate scope, covering different substitution patterns with different functional groups, ranging from unfunctionalized olefins, through olefins with poorly coordinative groups, to olefins with coordinative functional groups. α,β-Unsaturated acyclic and cyclic esters, ketones and amides werehydrogenated in enantioselectivities ranging from 83 to 99% ee. Enantioselectivities ranging from 91 to 98% ee were also achieved for challenging substrates such as unfunctionalized 1,1′-disubstituted olefins, functionalized tri- and 1,1′-disubstituted vinyl phosphonates, and β-cyclic enamides. The catalytic performance of the Ir-ligand assemblies was maintained when the environmentally benign 1,2-propylene carbonate was used as solvent. (Figure presented.).
- Margalef, Jèssica,Biosca, Maria,de la Cruz-Sánchez, Pol,Caldentey, Xisco,Rodríguez-Escrich, Carles,Pàmies, Oscar,Pericàs, Miquel A.,Diéguez, Montserrat
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supporting information
p. 4561 - 4574
(2021/04/05)
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- Formal Enone α-Arylation via I(III)-Mediated Aryl Migration/Elimination
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A formal enone α-arylation is described. This metal-free transformation relies on the I(III)-mediated skeletal reorganization of silyl enol ethers and features mild conditions, good yields, and high stereoselectivities for β-substituted enones.
- Martins, Bruna S.,Kaiser, Daniel,Bauer, Adriano,Tiefenbrunner, Irmgard,Maulide, Nuno
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supporting information
p. 2094 - 2098
(2021/04/05)
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- Tf2O/TTBP (2,4,6-Tri-tert-butylpyrimidine): An Alternative Amide Activation System for the Direct Transformations of Both Tertiary and Secondary Amides
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Ten types of Tf2O/TTBP-mediated amide transformation reactions were investigated. The results showed that compared with pyridine derivatives 2,6-di-tert-butyl-4-methylpyridine (DTBMP) and 2-fluoropyridine (2-F-Pyr.), TTBP can serve as an alternative amide activation system for the direct transformation of both secondary and tertiary amides. For most surveyed examples, higher or comparable yields were generally obtained. In addition, Tf2O/TTBP combination was used to promote the condensation reactions of 2-(tert-butyldimethylsilyloxy)furan (TBSOF) with both tertiary and secondary amides, the one-pot reductive Bischler-Napieralski-type reaction of tertiary lactams, and Movassaghi and Hill's modern version of the Bischler-Napieralski reaction. The value of the Tf2O/TTBP-based methodology was further demonstrated by the concise and high-yielding syntheses of several natural products.
- He, Qian,Ye, Jian-Liang,Xu, Fang-Fang,Geng, Hui,Chen, Ting-Ting,Chen, Hang,Huang, Pei-Qiang
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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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- PRODUCTION METHOD OF KETONE COMPOUND, AND PRODUCTION METHOD OF CARBOXYLIC ACID DERIVATIVE
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PROBLEM TO BE SOLVED: To provide a production method of a ketone compound that is able to use a substrate unstable under a basic condition and perform selective reduction in a simple process by using hydriodic acid under an acidic condition. SOLUTION: A production method of a ketone compound is characterized by producing a ketone compound by mixing a α,β-unsaturated carbonyl compound and hydriodic acid under an acidic condition and heating the mixture at 80 to 150°C as shown by formula (1). (R1 is H, a monovalent aliphatic hydrocarbon that may be substituted, a C1 to C12 alkyl group of a straight or blanched chain that may be substituted, an aromatic group that may be substituted, a nonaromatic heterocyclic group that may be substituted, a carboxyl group, a hydroxy group, and an amino group; any one or more groups of R2 to R4 are an aromatic group, and the remainder is H, a substituted or unsubstituted monovalent aliphatic hydrocarbon, and a substituted or unsubstituted monovalent aromatic ring group.) SELECTED DRAWING: None COPYRIGHT: (C)2021,JPOandINPIT
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Paragraph 0049-0051
(2021/01/21)
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- Asymmetric Umpolung Hydrogenation and Deuteration of Alkenes Catalyzed by Nickel
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Nickel-catalyzed asymmetric hydrogenation of several types of alkenes proceeds in high enantioselectivity, using acetic acid or water as the hydrogen source and indium powder as electron donor. The scope of alkenes herein include α,β-unsaturated esters, n
- Guo, Siyu,Wang, Xiuhua,Zhou, Jianrong Steve
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supporting information
p. 1204 - 1207
(2020/02/04)
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- Arylboronic Acid Catalyzed C-Alkylation and Allylation Reactions Using Benzylic Alcohols
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The arylboronic acid catalyzed dehydrative C-alkylation of 1,3-diketones and 1,3-ketoesters using secondary benzylic alcohols as the electrophile is reported, forming new C-C bonds (19 examples, up to 98% yield) with the release of water as the only byproduct. The process is also applicable to the allylation of benzylic alcohols using allyltrimethylsilane as the nucleophile (12 examples, up to 96% yield).
- Estopi?á-Durán, Susana,McLean, Euan B.,Donnelly, Liam J.,Hockin, Bryony M.,Taylor, James E.
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p. 7547 - 7551
(2020/10/09)
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- Radical Capture at Nickel(II) Complexes: C-C, C-N, and C-O Bond Formation
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The dinuclear β-diketiminato NiII tert-butoxide {[Me3NN]Ni}2(μ-OtBu)2 (2), synthesized from [Me3NN]Ni(2,4-lutidine) (1) and di-tert-butylperoxide, is a versatile precursor for the synthesis of a series of NiII complexes [Me3NN]Ni-FG (FG = functional group) to illustrate C-C, C-N, and C-O bond formation at NiII via radical capture. {[Me3NN]Ni}2(μ-OtBu)2 reacts with nitromethane, alkyl and aryl amines, acetophenone, benzamide, ammonia, and phenols to deliver the corresponding mono- or dinuclear [Me3NN]Ni-FG species (FG = O2NCH2, R-NH, ArNH, PhC(O)NH, PhC(O)CH2, NH2, and OAr). Many of these NiII complexes are capable of capturing the benzylic radical PhCH(?)CH3 to deliver the corresponding PhCH(FG)CH3 products featuring C-C, C-N, or C-O bonds. Density functional theory studies shed light on the mechanism of these transformations and suggest two competing pathways that depend on the nature of the functional groups. These radical capture reactions at [NiII]-FG complexes outline key C-C, C-N, and C-O bond forming steps, foreshadowing families of nickel radical relay catalysts.
- Bakhoda, Abolghasem Gus,Bertke, Jeffery A.,Figula, Bryan C.,Greene, Christine,Warren, Timothy H.,Wiese, Stefan
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supporting information
p. 1710 - 1718
(2020/07/13)
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- Synthesis and structural characterization of facile ruthenium(II) hydrazone complexes: Efficient catalysts in α-alkylation of ketones with primary alcohols via hydrogen auto transfer
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As a immersion for development of new complexes, new Ru(II) complexes (1–3) supported by benzothiazole hydrazine Schiff bases of the type [Ru(SAL-HBT)(CO)(AsPh3)2], [Ru(VAN-HBT)(CO)(AsPh3)2] and [Ru(NAP-HBT)(CO)Cl(AsPh3)2] [SAL-HBT = (salicyl((2-(benzothiazol-2yl)hydrazono)methylphenol)), VAN-HBT = 2-((2-(benzothiazol-2-yl)hydrazono)methyl)-6 methoxyphenol) and NAP-HBT = naphtyl-2-((2-(benzothiazol-2-yl)hydrazono)methyl phenol)] were synthesized. Their identities have been established by satisfactory elemental analyses, various spectroscopic techniques (IR, (1H, 13C) NMR) and also mass spectrometry. The ruthenium(II) ion exhibits a hexa coordination with distorted octahedral geometry. In complexes 1 and 2, the ligand coordinated as dianionic tridentate fashion by forming N^N donor five member and N^O donor six member chelate rings. However, in complex 3, the ligand coordinated as monoanionic bidentate fashion by forming N^N donor five-membered ring. The new ruthenium(II) carbonyl complexes were successfully applied as catalysts in α -alkylation of aliphatic and aromatic ketones with alcohols via borrowing hydrogen strategy. Various parameters such as base, solvent, temperature, time and catalyst loading on the catalytic activity were analyzed. From the results, the catalyst 1 was found to be the best catalyst for α-alkylation reaction to obtain excellent yield. The catalytic system has a broad substrate scope, which allows the synthesis of α-alkylated ketones in mild reaction conditions with low catalyst loading under air atmosphere.
- Kalaiarasi, Chinnasamy,Murugan, Kaliyappan,Vijayan, Paranthaman,Vijayapritha, Subbarayan,Viswanathamurthi, Periasamy
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supporting information
(2020/08/06)
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- Electrochemical 1,4-reduction of α,β-unsaturated ketones with methanol and ammonium chloride as hydrogen sources
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A sustainable, chemoselective 1,4-reduction of α,β-unsaturated ketones by means of an electrochemical method is presented, wherein the extremely inexpensive ammonium chloride (NH4Cl) is applied as the only additive. The reaction proceeds smoothly in the air at ambient temperature. Mechanistic studies reveal that both NH4Cl and solvent methanol work as hydrogen donors.
- Huang, Binbin,Li, Yanan,Yang, Chao,Xia, Wujiong
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supporting information
p. 6731 - 6734
(2019/06/17)
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- Benzylamine as Hydrogen Transfer Agent: Cobalt-Catalyzed Chemoselective C=C Bond Reduction of β-Trifluoromethylated α,β-Unsaturated Ketones via 1,5-Hydrogen Transfer
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An efficient cobalt-catalyzed chemoselective reduction of β-CF3-α,β-unsaturated ketones using benzylamine as hydrogen transfer agent involving intramolecular 1,5-hydrogen transfer is reported. The reaction proceeded smoothly with a relatively w
- Li, Xuewei,Wu, Xiaoting,Tang, Liang,Xie, Fang,Zhang, Wanbin
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supporting information
p. 3835 - 3839
(2019/11/11)
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- Giving a Second Chance to Ir/Sulfoximine-Based Catalysts for the Asymmetric Hydrogenation of Olefins Containing Poorly Coordinative Groups
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This work identifies a family of Ir/phosphite-sulfoximine catalysts that has been successfully used in the asymmetric hydrogenation of olefins with poorly coordinative or noncoordinative groups. In comparison with analogue Ir/phosphine-sulfoximine catalysts previously reported, the presence of a phosphite group extended the range of olefins than can be efficiently hydrogenated. High enantioselectivities, comparable to the best ones reported, have been achieved for a wide range of olefins containing relevant poorly coordinative groups such as α,β-unsaturated enones, esters, lactones, and lactams as well as alkenylboronic esters.
- Biosca, Maria,Pàmies, Oscar,Diéguez, Montserrat
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p. 8259 - 8266
(2019/06/17)
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- Enantioselective Cu-catalyzed 1,4-additions of organozinc and Grignard reagents to enones: Exceptional performance of the hydrido-phosphite-ligand BIFOP-H
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Enantioselective Cu(I),(II)-(i.e. CuCl, CuCl2, Cu(OTf)2)-catalyzed 1,4-additions of organozinc, i.e. (Et, Me)2Zn, and Grignard reagents, i.e. (Et, Me)MgBr, to chalcone, cyclohexenone and chromone are studied, employing fencholate-based phosphorus ligands, e.g. biphenyl-2,2′-bisfenchyl hydrido phosphite = BIFOP-H. The CuCl·BIFOP-H-catalyzed 1,4-addition of Et2Zn to chalcone yields up to 93% and 99% ee, exceeding established BINOL- and TADDOL-based phosphoramidite ligands. Remarkably, CuCl performs better in 1,4-additions to chalcone (CuCl: 76% ee; Cu(OTf)2: 49% ee; CuCl2: 42% ee) while Cu(OTf)2 performs better in 1,4-additions to cyclohexenone (Cu(OTf)2: 65% ee; CuCl: 20% ee). The computation of the reaction pathway is done for the CuI-catalyzed 1,4-addition to chalcone (CuII will be in situ reduced to CuI by a reagent, TPSS-D3(BJ)/def2-TZVP//B3LYP-D3(BJ)/def2-SVP) for six different model ligands, i.e. (MeO)2P-X (X = H, F, Me, OMe, NMe2 and PMe3). Origins of enantioselectivities are analyzed (M06-2X-D3/def2-TZVP//B3LYP-D3(BJ)/def2-SVP) for transition structures of the 1,4-methylation of chalcone with the Cu·BIFOP-H catalyst and explain the experimentally observed (R)-enantiomer's preference.
- Brüllingen, Eric,Neud?rfl, J?rg-Martin,Goldfuss, Bernd
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supporting information
p. 4787 - 4799
(2019/03/26)
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- Enantioselective conjugate hydrosilylation of α,β-unsaturated ketones
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Enantioselective conjugate hydrosilylation of β,β-disubstituted α,β-unsaturated ketones was realized. In the presence of a chiral picolinamide-sulfonate Lewis base catalyst, the reactions provided various chiral ketones bearing a chiral center at the β-po
- Yang, Huan,Weng, Guanglin,Fang, Dongmei,Peng, Changjiang,Zhang, Yuanyuan,Zhang, Xiaomei,Wang, Zhouyu
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p. 11627 - 11633
(2019/04/30)
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- One-Pot Conversion of Allylic Alcohols to α-Methyl Ketones via Iron-Catalyzed Isomerization-Methylation
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A one-pot iron-catalyzed conversion of allylic alcohols to α-methyl ketones has been developed. This isomerization-methylation strategy utilized a (cyclopentadienone)iron(0) carbonyl complex as precatalyst and methanol as the C1 source. A diverse range of allylic alcohols undergoes isomerization-methylation to form α-methyl ketones in good isolated yields (up to 84% isolated yield).
- Latham, Daniel E.,Polidano, Kurt,Williams, Jonathan M. J.,Morrill, Louis C.
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supporting information
p. 7914 - 7918
(2019/10/16)
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- Ketone Synthesis by Direct, Orthogonal Chemoselective Hydroacylation of Alkenes with Amides: Use of Alkenes as Surrogates of Alkyl Carbanions
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Direct functionalization of alkenes and direct transformation of carboxamides are two exciting areas that have attracted considerable attention in recent years. We report herein that secondary amides, the least reactive derivatives of carbonyl compounds, upon activated with triflic anhydride, can serve as effective hydroacylating reagents in partner with alkenes to yield ketones at ambient temperature. The method was applied to the one-step synthesis of racemic dihydro-ar-turmerone. In this method, alkenes serve as surrogates of organometallic reagents, which allows the orthogonal chemoselective reactions. The ready availability of many olefins such as camphene and norbornene permits one-step ketone synthesis that would require several steps by conventional methods.
- Geng, Hui,Huang, Pei-Qiang
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supporting information
(2019/07/08)
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- Α-Alkylation of Ketones with Secondary Alcohols Catalyzed by Well-Defined Cp*CoIII-Complexes
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Although α-alkylation of ketones with primary alcohols by transition-metal catalysis is well-known, the same process with secondary alcohols is arduous and complicated by self-condensation. Herein a well-defined, high-valence cobalt(III)-catalyst was applied for successful α-alkylation of ketones with secondary alcohols. A wide-variety of secondary alcohols, which include cyclic, acyclic, symmetrical, and unsymmetrical compounds, was employed as alkylating agents to produce β-alkyl aryl ketones.
- Chakraborty, Priyanka,Gangwar, Manoj Kumar,Emayavaramban, Balakumar,Manoury, Eric,Poli, Rinaldo,Sundararaju, Basker
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p. 3463 - 3467
(2019/07/05)
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- Graphene oxide catalyzed ketone α-alkylation with alkenes: Enhancement of graphene oxide activity by hydrogen bonding
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Direct α-alkylation of carbonyl compounds represents a fundamental bond forming transformation in organic synthesis. We report the first ketone-alkylation using olefins and alcohols as simple alkylating agents catalyzed by graphene oxide. Extensive studies of the graphene surface suggest a pathway involving dual activation of both coupling partners. Notably, we show that polar functional groups have a stabilizing effect on the GO surface, which results in a net enhancement of the catalytic activity. The method represents the first alkylation of carbonyl compounds using graphenes, which opens the door for the development of an array of protocols for ketone functionalization employing common carbonyl building blocks and readily available graphenes.
- Meng, Guangrong,Patel, Mehulkumar,Luo, Feixiang,Li, Qingdong,Flach, Carol,Mendelsohn, Richard,Garfunkel, Eric,He, Huixin,Szostak, Michal
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p. 5379 - 5382
(2019/05/10)
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- Ruthenium-Catalyzed β-Alkylation of Secondary Alcohols and α-Alkylation of Ketones via Borrowing Hydrogen: Dramatic Influence of the Pendant N-Heterocycle
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Three bidentate ruthenium(II) complexes with a pyridonate fragment were prepared and fully characterized. These complexes are structurally similar, but differ in their pendant substituents. Complex 1 contains a phenyl unit, whereas complexes 2 and 3 have uncoordinated thienyl and thiazolyl groups, respectively. These complexes were tested as catalysts for β-alkylation of secondary alcohols with primary alcohols, and 3 shows the highest activity, suggesting the thiazolyl ring participates in the catalytic process. Furthermore, 3 is an excellent catalyst for α-alkylation of ketones with primary alcohols. Various α-alkylated ketones were synthesized in high yields, by using 0.05 mol % 3 and 0.25 equiv of t-BuOK within 30 min.
- Zhang, Chong,Zhao, Jiong-Peng,Hu, Bowen,Shi, Jing,Chen, Dafa
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p. 654 - 664
(2019/02/17)
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- Polymer-Anchored Bifunctional Pincer Catalysts for Chemoselective Transfer Hydrogenation and Related Reactions
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A series of polymer-supported cooperative PC(sp3)P pincer catalysts was synthesized and characterized. Their catalytic activity in the acceptorless dehydrogenative coupling of alcohols and the transfer hydrogenation of aldehydes with formic acid as a hydrogen source was investigated. This comparative study, examining homogeneous and polymer-tethered species, proved that carefully designing a link between the support and the catalytic moiety, which takes into consideration the mechanism underlying the target transformation, might lead to superior heterogeneous catalysis.
- Mujahed, Shrouq,Valentini, Federica,Cohen, Shirel,Vaccaro, Luigi,Gelman, Dmitri
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p. 4693 - 4699
(2019/10/28)
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- Copper-catalyzed enantioselective 1,4-conjugate addition of dialkylzinc reagents to α,β- and α,β,γ,δ-unsaturated ketones
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An enantioselective Cu(II)-catalyzed conjugate addition of dialkylzinc reagents to α,β- or α,β,γ,δ-unsaturated ketones with chiral cyclohexane-based amidophosphine ligands was developed. With 2 mol% of Cu(OAc)2·H2O/L5, the conjugate
- Rexiti, Rukeya,Lu, Jian,Sha, Feng,Wu, Xin-Yan
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p. 3596 - 3604
(2019/06/04)
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- Chiral pyridylsulfonyl ester compound, and preparation method and application thereof
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The invention discloses a chiral pyridylsulfonyl ester compound, and a preparation method thereof. The compound is used as a Lewis base to activate trichlorosilane, and the activation of the trichlorosilane can realize the selective catalytic reduction of
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Paragraph 0089-0090; 0092; 0094
(2019/10/01)
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- Rhodium-Catalyzed Enantioconvergent Isomerization of Homoallylic and Bishomoallylic Secondary Alcohols
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We present herein an unprecedented enantioselective isomerization of homoallylic and bishomoallylic secondary alcohols, catalyzed by a commercially available rhodium-complex and a base. This catalytic redox-neutral process provides an effective access to chiral ketones in high efficiency and enantioselectivity, without the use of any stoichiometric reagent or generation of any waste. For the reaction of homoallylic alcohols, this system achieved not only a stereoconvergent access to chiral ketones bearing a β-stereocenter (up to 95%, 86% ee) but also a concomitant oxidative kinetic resolution of the alcohol substrates (S > 20). In the case of bishomoallylic alcohols, an intriguing ligand-induced divergent reactivity was observed. A terminal-to-internal alkene isomerization promoted by Rh/L7 followed by redox isomerization using Rh/BINAP system produced chiral ketones bearing a γ-stereocenter with high yield and enantioselectivity. Mechanistic studies provided strong support for the redox-isomerization pathway with chain walking of the key alkyl-Rh intermediate.
- Huang, Rui-Zhi,Lau, Kai Kiat,Li, Zhaofeng,Liu, Tang-Lin,Zhao, Yu
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p. 14647 - 14654
(2018/11/06)
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- Cobalt-Catalyzed Enantioselective Synthesis of Chiral gem-Bis(boryl)alkanes
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We report an asymmetric synthesis of enantioenriched gem-bis(boryl)alkanes in an enantioselective diborylation of 1,1-disubstituted alkenes catalyzed by Co(acac)2/(R)-DM-segphos. A range of activated and unactivated alkenes underwent this asymmetric diborylation in the presence of cyclooctene as a hydrogen acceptor, affording the corresponding gem-bis(boryl)alkanes with high enantioselectivity. The synthetic utility of these chiral organoboronate compounds was demonstrated through several stereospecific derivatizations and the synthesis of sesquiterpene and sesquiterpenoid natural products.
- Teo, Wei Jie,Ge, Shaozhong
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supporting information
p. 12935 - 12939
(2018/09/20)
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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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- NNN pincer Ru(II)-complex-catalyzed α-alkylation of ketones with alcohols
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A series of novel ruthenium(II) complexes supported by a symmetrical NNN ligand were prepared and fully characterized. These complexes exhibited good performance in transfer hydrogenation to form new C-C bonds using alcohols as the alkylating agents, generating water as the only byproduct. A broad range of substrates, including (hetero)aryl- or alkyl-ketones and alcohols, were well tolerated under the optimized conditions. Notably, α-substituted methylene ketones were also investigated, which afforded α-branched steric hindrance products. A potential application of α-alkylation of methylene acetone to synthesize donepezil was demonstrated, which provided the desired product in 83% yield. Finally, this catalytic system could be applied to a one-pot double alkylation procedure with sequential addition of two different alcohols. The current protocol is featured with several characteristics, including a broad substrate scope, low catalyst (0.50 mol %) loadings, and environmental benignity.
- Cao, Xiao-Niu,Wan, Xiao-Min,Yang, Fa-Liu,Li, Ke,Hao, Xin-Qi,Shao, Tian,Zhu, Xinju,Song, Mao-Ping
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p. 3657 - 3668
(2018/04/14)
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- Rhenium-catalyzed α-alkylation of enol acetates with alcohols or ethers
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When benzylic and allylic alcohols were treated with enol acetate in the presence of a catalytic amount of a rhenium complex, ReBr(CO)5, the carbon-carbon bond formation of the alcohols and enol acetate smoothly proceeded to give the corresponding ketones and aldehyde in moderate to good yields. For the reaction of allylic alcohols, γ,δ-unsaturated carbonyl compounds were obtained in good yields. When ethers were used instead of alcohols as the alkylated agent, two alkyl moieties on the ethers were utilized on the reaction.
- Umeda, Rui,Takahashi, Yuuki,Yamamoto, Takaaki,Iseki, Hideki,Osaka, Issey,Nishiyama, Yutaka
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supporting information
p. 92 - 101
(2018/11/01)
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- Pyrrolidine-Based P,O Ligands from Carbohydrates: Easily Accessible and Modular Ligands for the Ir-Catalyzed Asymmetric Hydrogenation of Minimally Functionalized Olefins
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The potential of P,O-iminosugar based ligands in the Ir-catalyzed asymmetric hydrogenation of minimally functionalized olefins is presented. These new ligands were prepared from easily available carbohydrates (D-mannose, D-ribose and D-arabinose). The stereochemical and polyfunctional diversity of carbohydrates allowed the modulation of the ligands, both from their electronic properties and the rigidity of their backbone. High enantioselectivities (ee’s up to 99 %) can be reached in the hydrogenation of selected tri- and disubstituted substrates.
- Elías-Rodríguez, Pilar,Borràs, Carlota,Carmona, Ana T.,Faiges, Jorge,Robina, Inmaculada,Pàmies, Oscar,Diéguez, Montserrat
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p. 5414 - 5424
(2018/12/11)
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- An Atom-Economical Route to Substituted β-Arylethyl Ketones: Phosphomolybdic Acid-Catalyzed Carbohydroxylation of Terminal Alkynes in Organic Carbonate
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A highly efficient and atom-economical route for the synthesis of substituted β-arylethyl ketones was developed by using cheap phosphomolybdic acid (H3PMo12O40) as catalyst and non-volatile propylene carbonate (PC) as green solvent via the carbohydroxylation of terminal alkynes with benzylic alcohols under mild conditions. Various functional groups on the benzylic alcohols and terminal alkynes were tolerated, giving the corresponding substituted β-arylethyl ketones as products in good to excellent yields (up to 95%). It is worth noting that a turnover number (TON) of up to 520 was achieved in the protocol. The mechanism investigation showed that PC might stabilize the heteropoly anion and the carbocation intermediate thus facilitating the carbohydroxylation reaction. (Figure presented.).
- Yang, Guo-Ping,Zhang, Nan,Ma, Nuan-Nuan,Yu, Bing,Hu, Chang-Wen
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p. 926 - 932
(2017/03/27)
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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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supporting information
p. 9258 - 9261
(2017/08/22)
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- Hydrogen Borrowing Catalysis with Secondary Alcohols: A New Route for the Generation of β-Branched Carbonyl Compounds
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A hydrogen borrowing reaction employing secondary alcohols and Ph? (Me5C6) ketones to give β-branched carbonyl products is described (21 examples). This new C-C bond forming process requires low loadings of [Cp?IrCl2]2, relatively low temperatures, and up to 2.0 equiv of the secondary alcohol. Substrate-induced diastereoselectivity was observed, and this represents the first example of a diastereoselective enolate hydrogen borrowing alkylation. By utilizing the Ph? group, the β-branched products could be straightforwardly cleaved to the corresponding esters or amides using a retro-Friedel-Crafts reaction. Finally, this protocol was applied to the synthesis of fragrance compound (±)-3-methyl-5-phenylpentanol.
- Akhtar, Wasim M.,Cheong, Choon Boon,Frost, James R.,Christensen, Kirsten E.,Stevenson, Neil G.,Donohoe, Timothy J.
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supporting information
p. 2577 - 2580
(2017/03/01)
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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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p. 4738 - 4742
(2016/04/05)
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- Catalytic Carbocation Generation Enabled by the Mesolytic Cleavage of Alkoxyamine Radical Cations
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A new catalytic method is described to access carbocation intermediates via the mesolytic cleavage of alkoxyamine radical cations. In this process, electron transfer between an excited state oxidant and a TEMPO-derived alkoxyamine substrate gives rise to a radical cation with a remarkably weak C?O bond. Spontaneous scission results in the formation of the stable nitroxyl radical TEMPO.as well as a reactive carbocation intermediate that can be intercepted by a wide range of nucleophiles. Notably, this process occurs under neutral conditions and at comparatively mild potentials, enabling catalytic cation generation in the presence of both acid sensitive and easily oxidized nucleophilic partners.
- Zhu, Qilei,Gentry, Emily C.,Knowles, Robert R.
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p. 9969 - 9973
(2016/08/16)
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- Base-Catalyzed Stereospecific Isomerization of Electron-Deficient Allylic Alcohols and Ethers through Ion-Pairing
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A mild base-catalyzed strategy for the isomerization of allylic alcohols and allylic ethers has been developed. Experimental and computational investigations indicate that transition metal catalysts are not required when basic additives are present. As in the case of using transition metals under basic conditions, the isomerization catalyzed solely by base also follows a stereospecific pathway. The reaction is initiated by a rate-limiting deprotonation. Formation of an intimate ion pair between an allylic anion and the conjugate acid of the base results in efficient transfer of chirality. Through this mechanism, stereochemical information contained in the allylic alcohols is transferred to the ketone products. The stereospecific isomerization is also applicable for the first time to allylic ethers, yielding synthetically valuable enantioenriched (up to 97% ee) enol ethers.
- Martinez-Erro, Samuel,Sanz-Marco, Amparo,Bermejo Gómez, Antonio,Vázquez-Romero, Ana,Ahlquist, M?rten S. G.,Martín-Matute, Belén
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supporting information
p. 13408 - 13414
(2016/10/22)
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- Cu-Ag/hydrotalcite catalysts for dehydrogenative cross-coupling of primary and secondary benzylic alcohols
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The development of new and inexpensive heterogeneous catalysts for direct C-C cross-coupling of primary and secondary alcohols is a challenging goal and has great importance in academic and industrial sectors. In this work Cu-Ag/hydrotalcite (Cu-Ag/HT) catalysts were prepared and tested for their impact on this cross-coupling. The effect of supports, including MgO, γ-Al2O3 and HT with different Mg : Al molar ratios, was investigated. It was found that the acidic or basic properties of the supports affected product selectivity. The roles of Cu and Ag sites in the cross-coupling were also investigated with the prepared Cu-Ag/HT catalyst demonstrating high activity and selectivity for the reaction. The yield-to-target product of β-phenylpropiophenone reached 99% after 1 h under optimum reaction conditions. The stability in air and reusability studies show that Cu-Ag/HT can be stored for 6 days and can be used five times without apparent deactivation, respectively.
- Xu, Jin,Yue, Hongmei,Liu, Sheng,Wang, Hanfei,Du, Yuqun,Xu, Chunli,Dong, Wensheng,Liu, Chunling
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p. 24164 - 24174
(2016/03/15)
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- Cyclopentanone as a cation-stabilizing electron-pair donor in the calcium-catalyzed intermolecular carbohydroxylation of alkynes
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Although they have been used as reactivity-controlling additives in cationic polymerizations for decades, Lewis basic electron pair donor (ED) compounds were never used for the stabilization of cationic intermediates in transformations of small molecules. As such an ED, cyclopentanone proved highly efficient for the stabilization of allyl and vinyl cations in combination with our calcium-based catalyst system. Therefore, the first general transition-metal-free intermolecular carbohydroxylation of alkynes with allyl and propargyl alcohols was realized.
- Stopka, Tobias,Niggemann, Meike
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supporting information
p. 1437 - 1440
(2015/03/30)
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- Synthesis of Substituted Aryl Ketones by Addition of Alcohols to Alkynes Using Amberlyst-15/Ionic Liquid as a Recyclable Catalytic System
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A highly efficient protocol for the synthesis of substituted aryl ketones by using Amberlyst-15 immobilized in [Bmim][PF6] ionic liquid has been firstly developed. The present protocol works under metal-free, solvent-free, mild reaction conditions with 100% atom efficiency. The various aryl ketones were obtained in good to excellent yields. The developed catalytic system was recycled efficiently up to five cycles without significant loss in catalytic activity.
- Wagh, Kishor V.,Bhanage, Bhalchandra M.
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supporting information
p. 759 - 764
(2015/03/30)
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- METHOD FOR ALKYLATING KETONE
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PROBLEM TO BE SOLVED: To provide a method for alkylating a ketone capable of alkylating a ketone with one-step reaction using a ketone body as is as a raw material under reaction conditions at approximately room temperature and easily performing post-trea
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Paragraph 0068; 0069
(2017/03/18)
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- Efficient asymmetric synthesis of structurally diverse p-stereogenic phosphinamides for catalyst design
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The use of chiral phosphinamides is relatively unexplored because of the lack of a general method for the synthesis. Reported herein is the development of a general, efficient, and highly enantioselective method for the synthesis of structurally diverse P-stereogenic phosphinamides. The method relies on nucleophilic substitution of a chiral phosphinate derived from the versatile chiral phosphinyl transfer agent 1,3,2-benzoxazaphosphinine-2-oxide. These chiral phosphinamides were utilized for the first synthesis of readily tunable P-stereogenic Lewis base organocatalysts, which were used successfully for highly enantioselective catalysis.
- Han, Zhengxu S.,Zhang, Li,Xu, Yibo,Sieber, Joshua D.,Marsini, Maurice A.,Li, Zhibin,Reeves, Jonathan T.,Fandrick, Keith R.,Patel, Nitinchandra D.,Desrosiers, Jean-Nicolas,Qu, Bo,Chen, Anji,Rudzinski, Diandra M.,Samankumara, Lalith P.,Ma, Shengli,Grinberg, Nelu,Roschangar, Frank,Yee, Nathan K.,Wang, Guijun,Song, Jinhua J.,Senanayake, Chris H.
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supporting information
p. 5474 - 5477
(2015/04/27)
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- Peroxide promoted tunable decarboxylative alkylation of cinnamic acids to form alkenes or ketones under metal-free conditions
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A tunable decarboxylative alkylation of cinnamic acids with alkanes was developed to form alkenes or ketones under transition metal-free conditions. In the presence of DTBP or DTBP/TBHP, the reaction gave alkenes and ketones respectively via a radical mechanism in moderate to good yields. This journal is
- Ji, Jing,Liu, Ping,Sun, Peipei
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supporting information
p. 7546 - 7549
(2015/05/04)
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- Transition-Metal-Free Self-Hydrogen-Transferring Allylic Isomerization
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Phenanthroline and tert-butoxide have been established as powerful radical initiators in reactions such as the SRN1-type coupling reactions due to the cooperation of large heteroarenes and a special feature of tert-butoxide. The first phenanthroline-tert-butoxide-catalyzed transition-metal-free allylic isomerization is described. The resulting ketones are key intermediates for indenes. The control experiments rule out the base-promoted allylic anion pathway. The radical pathway is supported by experimental evidence that includes kinetic study, kinetic isotope effect, isotope-labeling experiments, trapping experiments, and EPR experiments.
- Zheng, Hong-Xing,Xiao, Zu-Feng,Yao, Chuan-Zhi,Li, Qiang-Qiang,Ning, Xiao-Shan,Kang, Yan-Biao,Tang, Yong
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supporting information
p. 6102 - 6105
(2016/01/09)
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- Alcohols as electrophiles: Iron-catalyzed Ritter reaction and alcohol addition to alkynes
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A simple, iron-based catalytic system allows for a straightforward method for the synthesis of primary, secondary, and tertiary amides. The system also allows the addition of benzyl alcohols across phenylacetylene to produce substituted phenyl ketones. This transformation improves and expands the substrate scope beyond that previously reported and proceeds under mild reaction conditions, tolerating air and moisture.
- Jefferies, Latisha R.,Cook, Silas P.
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supporting information
p. 4204 - 4207
(2014/06/09)
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- Rhenium complex-catalyzed coupling reaction of enol acetates with alcohols
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The reaction of enol acetates with alcohols in the presence of a catalytic amount of a rhenium complex, such as ReBr(CO)5, produced the corresponding ketones and aldehydes in moderate to good yields. It was suggested that the preparation of an ether, an intermolecular dehydrated product, was the first step of the reaction.
- Umeda, Rui,Takahashi, Yuuki,Nishiyama, Yutaka
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p. 6113 - 6116
(2015/01/09)
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- BINAM- mono -PHOS as new entry for multinuclear copper catalysts in asymmetric conjugate addition of organozinc reagents
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The readily functionalized ligands, BINAM-PHOS, participate in the copper-catalyzed asymmetric conjugate addition of organozinc reagents to enones. The incorporation of benzoyl derivatives on nitrogen atoms was crucial to promote the reaction. Notably, BI
- Endo, Kohei,Takayama, Ryotaro,Shibata, Takanori
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p. 1155 - 1159
(2013/06/27)
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