- Synthesis of α-Alkylated Ketones via Selective Epoxide Opening/Alkylation Reactions with Primary Alcohols
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A new method for converting terminal epoxides and primary alcohols into α-alkylated ketones under borrowing hydrogen conditions is reported. The procedure involves a one-pot epoxide ring opening and alkylation via primary alcohols in the presence of an N-heterocyclic carbene iridium(I) catalyst, under aerobic conditions, with water as the side product.
- Gen?, Serta?,Gülcemal, Süleyman,Günnaz, Salih,?etinkaya, Bekir,Gülcemal, Derya
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supporting information
p. 5229 - 5234
(2021/07/19)
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- Electrochemical-Induced Hydrogenation of Electron-Deficient Internal Olefins and Alkynes with CH3OH as Hydrogen Donor
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Efficient hydrogenation of electron-deficient internal olefins and alkynes access to saturate ketone with CH3OH as a single hydrogen donor under electrochemical conditions has been successfully developed. This hydrogenation strategy can be used to convert electron-deficient internal olefins and alkynes to saturate ketone under electrochemical conditions with exogenous-reductant and a metal catalyst. Mechanistic studies reveal that radical hydrogenation was involved in this transformation. Notably, various electron-deficient internal olefins and alkynes could be tolerated in such an electrochemical hydrogenation synthetic strategy and can be easily scaled up with good efficiency. (Figure presented.).
- Qin, Hongyun,Yang, Jianjing,Yan, Kelu,Xue, Yaxuan,Zhang, Meichen,Sun, Xuejun,Wen, Jiangwei,Wang, Hua
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supporting information
p. 2104 - 2109
(2021/03/15)
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- Borane-Catalyzed, Chemoselective Reduction and Hydrofunctionalization of Enones Enabled by B-O Transborylation
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The use of stoichiometric organoborane reductants in organic synthesis is well established. Here these reagents have been rendered catalytic through an isodesmic B-O/B-H transborylation applied in the borane-catalyzed, chemoselective alkene reduction and formal hydrofunctionalization of enones. The reaction was found to proceed by a 1,4-hydroboration of the enone and B-O/B-H transborylation with HBpin, enabling catalyst turnover. Single-turnover and isotopic labeling experiments supported the proposed mechanism of catalysis with 1,4-hydroboration and B-O/B-H transborylation as key steps.
- Nicholson, Kieran,Langer, Thomas,Thomas, Stephen P.
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p. 2498 - 2504
(2021/04/13)
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- Unveiling the catalytic nature of palladium-N-heterocyclic carbene catalysts in the α-alkylation of ketones with primary alcohols
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We report herein the synthesis of four new Pd-PEPPSI complexes with backbone-modified N-heterocyclic carbene (NHC) ligands and their application as catalysts in the α-alkylation of ketones with primary alcohols using a borrowing hydrogen process and tandem Suzuki-Miyaura coupling/α-alkylation reactions. Among the synthesized Pd-PEPPSI complexes, complex2chaving 4-methoxyphenyl groups at the 4,5-positions and 4-methoxybenzyl substituents on the N-atoms of imidazole exhibited the highest catalytic activity in the α-alkylation of ketones with primary alcohols (18 examples) with yields reaching up to 95%. Additionally, complex2cwas demonstrated to be an effective catalyst for the tandem Suzuki-Miyaura-coupling/α-alkylation of ketones to give biaryl ketones with high yields. The heterogeneous nature of the present catalytic system was verified by mercury poisoning and hot filtration experiments. Moreover, the formation of NHC-stabilized Pd(0) nanoparticles during the α-alkylation reactions was identified by advanced analytical techniques.
- ?etinkaya, Bekir,Ero?lu, Zafer,Gülcemal, Süleyman,Metin, ?nder,Ovezova, Mamajan
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supporting information
p. 10896 - 10908
(2021/08/17)
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- Efficient Generation and Synthetic Applications of Alkyl-Substituted Siloxycarbenes: Suppression of Norrish-Type Fragmentations of Alkanoylsilanes by Triplet Energy Transfer
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Acylsilanes have been known to undergo isomerization to siloxycarbenes under photoirradiation and the thus generated carbenes can be utilized for various synthetic reactions. But this carbene formation is not necessarily efficient with some alkanoylsilanes because Norrish-type fragmentations compete, which limit the synthetic utility of alkanoylsilanes as carbene precursors. In this study, generation of siloxycarbenes from alkanoylsilanes by visible-light-induced energy transfer was examined by using an Ir complex, [Ir{dF(CF3)ppy}2(dtbpy)]PF6, and was successfully applied to the C?C coupling reactions with boronic esters or aldehydes. This methodology efficiently suppressed undesired Norrish-type reactions and broadened synthetic utility of alkanoylsilanes.
- Abe, Manabu,Hagiwara, Chihiro,Ishida, Kento,Kusama, Hiroyuki,Yamazaki, Hokuto
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p. 1249 - 1253
(2020/02/04)
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- Sustainable and Selective Alkylation of Deactivated Secondary Alcohols to Ketones by Non-bifunctional Pincer N-heterocyclic Carbene Manganese
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A sustainable and green route to access diverse functionalized ketones via dehydrogenative–dehydrative cross-coupling of primary and secondary alcohols is demonstrated. This borrowing hydrogen approach employing a pincer N-heterocyclic carbene Mn complex displays high activity and selectivity. A variety of primary and secondary alcohols are well tolerant and result in satisfactory isolated yields. Mechanistic studies suggest that this reaction proceeds via a direct outer-sphere mechanism and the dehydrogenation of the secondary alcohol substrates plays a vital role in the rate-limiting step.
- Lan, Xiao-Bing,Ye, Zongren,Liu, Jiahao,Huang, Ming,Shao, Youxiang,Cai, Xiang,Liu, Yan,Ke, Zhuofeng
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p. 2557 - 2563
(2020/05/04)
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- Alkylation synthesis method of in-situ catalytic alcohol (by machine translation)
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The method comprises VIB metal complexes, an auxiliary ligand and a base as a catalytic reaction system, wherein the alcohol serves as an alkylating agent, and the nucleophilic substrate is subjected to in-situ catalytic alkylation reaction in a solvent and an inert gas atmosphere. The catalytic system has a wide application range on a substrate, can catalyze the synthesis of C-N and C-C bond compounds of different structures under mild conditions, and can green synthesize a series of valuable N - alkylation and C - alkylation compounds. (by machine translation)
- -
-
Paragraph 0147-0149; 0156-0158
(2020/11/01)
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- Selective Ketone Formations via Cobalt-Catalyzed β-Alkylation of Secondary Alcohols with Primary Alcohols
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A homogeneous cobalt-catalyzed β-alkylation of secondary alcohols with primary alcohols to selectively synthesize ketones via acceptorless dehydrogenative coupling is reported for the first time. Notably, this transformation is environmentally benign and atom economical with water and hydrogen gas as the only byproducts.
- Pandey, Bedraj,Xu, Shi,Ding, Keying
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supporting information
p. 7420 - 7423
(2019/10/02)
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- Ligand-controlled phosphine-free Co(II)-catalysed cross-coupling of secondary and primary alcohols
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Cobalt(II) complexes (5 mol% Co) bearing phosphine-free N?N?N pincer ligands efficiently catalyze C–C coupling of secondary and primary alcohols to selectively form α-alkylated ketones with a good functional group compatibility using NaOH (20 mol%) as a base at 120 °C. The NH group on the N?N?N–Co(II) precatalyst controls the activity and selectivity. This simple catalytic system is involved in the synthesis of quinolones via the dehydrogenative annulation of 2-aminobenzyl alcohols with secondary alcohols.
- Zhang, Shi-Qi,Guo, Bin,Xu, Ze,Li, Hong-Xi,Li, Hai-Yan,Lang, Jian-Ping
-
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- Chemoselective Hydrogenation of α,β-Unsaturated Carbonyls Catalyzed by Biomass-Derived Cobalt Nanoparticles in Water
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Herein, we report highly chemoselective hydrogenation of α,β-unsaturated carbonyls to saturated carbonyls catalyzed by cobalt nanoparticles supported on the biomass-derived carbon from bamboo shoots with molecular hydrogen in water, which is the first prototype using a heterogeneous non-noble metal catalyst for such organic transformation as far as we know. The optimal cobalt nanocatalyst, CoOx@NC-800, manifested remarkable activity and selectivity for hydrogenation of C=C in α,β-unsaturated carbonyls under mild conditions. A broad set of α,β-aromatic and aliphatic unsaturated carbonyls were selectively reduced to their corresponding saturated carbonyls in up to 99 % yields with good tolerance of various functional groups. Meanwhile, a new straightforward one-pot cascade synthesis of saturated carbonyls was realized with high activity and selectivity via the cross-aldol condensation of ketones with aldehydes followed by selective hydrogenation. More importantly, this one-pot strategy is applicable for the expedient synthesis of Loureirin A, a versatile bioactive and medicinal molecule, from readily available starting materials, further highlighting the practical utility of the catalyst. In addition, the catalyst can be easily separated for successive reuses without significant loss in both activity and selectivity.
- Song, Tao,Ma, Zhiming,Yang, Yong
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p. 1313 - 1319
(2019/01/25)
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- Chemoselective transfer hydrogenation of Α,Β-unsaturated carbonyls catalyzed by a reusable supported Pd nanoparticles on biomass-derived carbon
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We herein report highly chemoselective transfer hydrogenation of α,β-unsaturated carbonyl compounds to saturated carbonyls with formic acid as a hydrogen donor over a stable and recyclable heterogeneous Pd nanoparticles (NPs) on N,O-dual doped hierarchical porous biomass-derived carbon. The synergistic effect between Pd NPs and incorporated heteroatoms on carbon plays a critical role on promoting the reaction efficiency. A series of α,β-aromatic and aliphatic unsaturated carbonyl compounds was selectively reduced to their corresponding saturated carbonyls in up to 97% isolated yields with good tolerance of various functional groups. In addition, the catalyst can be successively reused for at least 6 times without significant loss in reaction efficiency.
- Song, Tao,Duan, Yanan,Yang, Yong
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- Nonbifunctional Outer-Sphere Strategy Achieved Highly Active α-Alkylation of Ketones with Alcohols by N-Heterocyclic Carbene Manganese (NHC-Mn)
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The unusual nonbifunctional outer-sphere strategy was successfully utilized in developing an easily accessible N-heterocyclic carbene manganese (NHC-Mn) system for highly active α-alkylation of ketones with alcohols. This system was efficient for a wide range of ketones and alcohols under mild reaction conditions, and also for the green synthesis of quinoline derivatives. The direct outer-sphere mechanism and the high activity of the present system demonstrate the potential of nonbifunctional outer-sphere strategy in catalyst design for acceptorless dehydrogenative transformations.
- Lan, Xiao-Bing,Ye, Zongren,Huang, Ming,Liu, Jiahao,Liu, Yan,Ke, Zhuofeng
-
supporting information
p. 8065 - 8070
(2019/10/11)
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- Palladium on carbon-catalyzed Α-alkylation of ketones with alcohols as electrophiles: Scope and mechanism
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The α-alkylation of ketones with alcohols represents a green strategy for the formation of crucial carbon–carbon bonds since it only produces water as byproduct. In terms of reaction mechanism, the evidence for homogeneous catalysis supports a catalytic hydrogen-borrowing pathway; however, the reaction mechanism has not been investigated for heterogeneous Pd/C catalysts. Here, we report an improved method for α-alkylation of ketones with alcohols using commercially available Pd/C, ubiquitous in organic synthesis labs, as catalyst. The reaction conditions are mild compared to state-of-the-art for both homo- and heterogeneous catalysts, and the developed conditions produces quantitative yields for most ketones and alcohols. A hot filtration experiment and recycling of the catalyst supports the heterogeneous nature of catalysis. Importantly, the reaction mechanism is studied for the first time by a combination of stoichiometric experiments and kinetic analyses by in-situ IR (React-IR).
- Bennedsen, Niklas R.,Mortensen, Rasmus L.,Kramer, S?ren,Kegn?s, S?ren
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p. 153 - 160
(2019/02/14)
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- Cobalt-Catalyzed Chemoselective Transfer Hydrogenation of C=C and C=O Bonds with Alkanols
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An environmentally benign protocol of chemoselective transfer hydrogenation of C=C and C=O bonds with alkanols under base-free conditions is developed by this study, wherein the cobalt- bidentate phosphine catalyst precursor is commercially available and
- Jiang, Biao-Lin,Ma, Shuang-Shuang,Wang, Meng-Liang,Liu, Dian-Sheng,Xu, Bao-Hua,Zhang, Suo-Jiang
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p. 1701 - 1706
(2019/03/08)
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- C?C Bond Formation of Benzyl Alcohols and Alkynes Using a Catalytic Amount of KOtBu: Unusual Regioselectivity through a Radical Mechanism
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We report a C?C bond-forming reaction between benzyl alcohols and alkynes in the presence of a catalytic amount of KOtBu to form α-alkylated ketones in which the C=O group is located on the side derived from the alcohol. The reaction proceeds under thermal conditions (125 °C) and produces no waste, making the reaction highly atom efficient, environmentally benign, and sustainable. Based on our mechanistic investigations, we propose that the reaction proceeds through radical pathways.
- Kumar, Amit,Janes, Trevor,Chakraborty, Subrata,Daw, Prosenjit,von Wolff, Niklas,Carmieli, Raanan,Diskin-Posner, Yael,Milstein, David
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supporting information
p. 3373 - 3377
(2019/02/14)
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- Dirhodium(ii)/P(t-Bu)3 catalyzed tandem reaction of α,β-unsaturated aldehydes with arylboronic acids
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Phosphine ligated dirhodium(ii) acetate is advocated as a catalyst for the synthesis of aryl alkyl ketones by the tandem reaction of α,β-unsaturated aromatic or aliphatic aldehydes with arylboronic acids. This tandem procedure included arylation followed by the isomerization reaction. This method exhibits good functional group tolerance and has a broad substrate scope. With the conjugated aldehydes, the one-step synthesis of γ,δ-unsaturated ketones was realized through this reaction. It is noteworthy that the length of the Rh-P bond is an important factor affecting catalytic reactions. The comparative analysis of the crystal structures of axially alkylphosphane and arylphosphane ligated dirhodium(ii) acetate revealed that the shorter Rh-P bond length favors the isomerization process as compared to the longer one. In addition, the dirhodium(ii) compound can be recovered after the completion of the reaction.
- Ma, Ziling,Wang, Yuanhua
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supporting information
p. 7470 - 7476
(2018/10/24)
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- Catalyst-free chemoselective conjugate addition and reduction of α,β-unsaturated carbonyl compounds: Via a controllable boration/protodeboronation cascade pathway
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A novel, efficient transition-metal-free and controllable boration/protodeboronation strategy has been developed for the chemoselective conjugate addition and 1,4-reduction of α,β-unsaturated carbonyl compounds. Without any metal-catalyst or base, a series of β-boration products of α,β-unsaturated carbonyl compounds was easily obtained in moderate to excellent yields in a mixed solvent of ethanol and water. The presence of a catalytic amount of Cs2CO3 can effectively induce further protodeboronation reaction towards 1,4-reduction products at higher reaction temperature. Therefore, by slightly changing the reaction conditions, the boration or reduction products of α,β-unsaturated carbonyl compounds can be controllably obtained. Mechanistic studies revealed that Cs2CO3 played the key role in activating the protodeboronation step. This transition-metal-catalyst-free and product controllable method provides a useful and eco-friendly tool for the highly chemoselective preparation of the β-boration products and 1,4-reduction products of α,β-unsaturated carbonyl compounds.
- Huang, Xi,Hu, Junjie,Wu, Mengying,Wang, Jiayi,Peng, Yanqing,Song, Gonghua
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p. 255 - 260
(2018/01/12)
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- Solvent-free direct α-alkylation of ketones by alcohols catalyzed by nickel supported on silica-alumina
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The α-alkylation of acetophenone with benzyl alcohol through borrowing hydrogen has been studied using nickel catalysis. Ni/SiO2-Al2O3 was found to be the best catalyst for this transformation and the corresponding alkylated acetophenone was obtained with 93% isolated yield. Following the objectives of clean and sustainable chemistry, the reaction occurs under solvent-free conditions and requires only a catalytic amount of base. This protocol was next applied to a wide range of ketones and alcohols and the desired products were isolated with 18-86% yields (26 examples). The recovery and recyclability of the nickel catalyst was also investigated and it was found to be active over 5 runs without significant loss of activity. Surprisingly, the active catalyst appears to include an amorphous nickel hydroxide layer.
- Charvieux, Aubin,Giorgi, Javier B.,Duguet, Nicolas,Métay, Estelle
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supporting information
p. 4210 - 4216
(2018/10/02)
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- Method for synthesizing alpha-alkyl ketone
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The invention discloses a method for synthesizing alpha-alkyl ketone, and especially includes the following steps of: in a reaction vessel, adding secondary alcohol, a transition metal catalyst, and a solvent tertiary amyl alcohol; and heating and refluxing a reaction mixture in an oil bath for several hours, cooling the mixture to a room temperature; then adding primary alcohol and alkali, heating and refluxing the reaction mixture for several hours, and then obtaining a target compound through column separation. The method for synthesizing the alpha-alkyl ketone starts from the primary alcohol and the secondary alcohol. With the participation of the transition metal catalyst, the alpha-alkyl ketone is generated through a serial secondary alcohol non-acceptor dehydrogenation oxidation reaction/alpha-alkylation reaction of ketone. The reaction shows three obvious advantages that 1) non-toxic alcohols are used as the starting materials; 2) only hydrogen and water are generated in the reaction without environmental hazards; 3) atomic economy is high in the reaction; and 4) only 0.1 equivalents of carbonate is needed for the reaction, and the reaction only takes 3-6 hours. Therefore, the reaction meets the requirements of green chemistry and has broad development prospects.
- -
-
Paragraph 0148; 0149; 0150; 0151; 0152
(2017/04/12)
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- Alkylation of Ketones Catalyzed by Bifunctional Iron Complexes: From Mechanistic Understanding to Application
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Cyclopentadienone iron dicarbonyl complexes were applied in the alkylation of ketones with various aliphatic and aromatic ketones and alcohols via the borrowing hydrogen strategy in mild reaction conditions. DFT calculations and experimental works highlight the role of the transition metal Lewis pairs and the base. These iron complexes demonstrated a broad applicability in mild conditions and extended the scope of substrates.
- Seck, Charlotte,Mbaye, Mbaye Diagne,Coufourier, Sébastien,Lator, Alexis,Lohier, Jean-Fran?ois,Poater, Albert,Ward, Thomas R.,Gaillard, Sylvain,Renaud, Jean-Luc
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p. 4410 - 4416
(2017/11/20)
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- Cobalt-Catalyzed α-Alkylation of Ketones with Primary Alcohols
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An ionic cobalt-PNP complex is developed for the efficient α-alkylation of ketones with primary alcohols for the first time. A broad range of ketone and alcohol substrates were employed, leading to the isolation of alkylated ketones with yields up to 98%. The method was successfully applied to the greener synthesis of quinoline derivatives while using 2-aminobenzyl alcohol as an alkylating reagent.
- Zhang, Guoqi,Wu, Jing,Zeng, Haisu,Zhang, Shu,Yin, Zhiwei,Zheng, Shengping
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supporting information
p. 1080 - 1083
(2017/03/14)
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- Hydrogen autotransfer and related dehydrogenative coupling reactions using a rhenium(i) pincer catalyst
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A novel rhenium complex bearing a non-innocent PNP pincer ligand was prepared. This novel catalyst is active in hydrogen autotransfer reactions to form new C-C and C-N bonds. More specifically, valuable alkylations of ketones and sulfonamides with primary alcohols are herein presented. In addition, the first examples of rhenium-catalysed synthesis of pyrroles are described by dehydrogenative coupling of diols, amines and ketones.
- Piehl, Patrick,Pe?a-López, Miguel,Frey, Anna,Neumann, Helfried,Beller, Matthias
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supporting information
p. 3265 - 3268
(2017/03/20)
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- A method for synthesis of α-alkyl ketone
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The invention discloses a method for synthesizing alpha-alkyl ketone. The method comprises the following steps: adding alkyne, [(IPr)AuCl], AgOTf, 1,4-dioxane and water in a reaction container, performing microwave reaction on a reaction mixture for 1h at 120 DEG C and cooling to room temperature; further adding [Cp*IrCl2]2, alkali and alcohol into the reaction mixture, performing microwave reaction on the reaction mixture for 2h at 130 DEG C and cooling to room temperature; filtering, performing rotary evaporation to remove a solvent, and then separating by a column to obtain a target compound. The method disclosed by the invention is started from chemical raw materials which are easy to obtain, namely alkyne, water and alcohol, alpha-alkyl ketone is obtained under the participation of gold and iridium catalysts, and the reaction only generates water as a byproduct. Therefore, the reaction is in line with the requirements of green chemistry and has broad development prospects.
- -
-
Paragraph 0155; 0156; 0157; 0158
(2016/11/28)
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- Rhodium-catalyzed alkylation of ketones and alcohols with alcohols
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An efficient method for direct alkylation of ketones and alcohols through the borrowing hydrogen strategy in the presence of rhodium complexes as catalyst was developed. This transformation is tolerant to various functional substrates and is efficient in C-C coupling of primary and secondary alcohols, which provides an alternative method of the synthesis of functional ketones from simple and commercially available materials.
- Yu,Wang,Wu,Wang
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p. 178 - 183
(2016/03/12)
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- Method for synthesizing alpha-alkyl ketone
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The invention discloses a method for synthesizing alpha-alkyl ketone. The method comprises the following steps: adding ketone, a compound alcohol, an iridium complex catalyst, an alkali and a solvent tert-amyl alcohol in a reaction container, carrying out a refluxing reaction on the above obtained reaction mixture in air for several hours, cooling the obtained reaction product to room temperature, carrying out rotary evaporation to remove the solvent, and carrying out column separation to obtain the target compound. The meta-organic bifunctional iridium complex is used, only 0.1 equivalent carbonate is added in the reaction process, and the reaction is carried in air for 6h, so obvious advantages are displayed; and the reaction accords with green chemistry requirements, and has wide development prospect.
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-
Paragraph 0145; 0146; 0147; 0148; 0149
(2016/10/07)
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- Manganese-Catalyzed Hydrogen-Autotransfer C?C Bond Formation: α-Alkylation of Ketones with Primary Alcohols
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A novel catalytic hydrogen-autotransfer protocol for the atom-efficient α-alkylation of ketones with readily available alcohols is presented. The use of manganese complexes bearing non-innocent PNP pincer ligands enabled the functionalization of a broad range of valuable ketones, including 2-oxindole, estrone 3-methyl ether, and testosterone. Mechanistic investigations suggest the participation of an intramolecular amidate-assisted alcohol-dehydrogenation process.
- Pe?a-López, Miguel,Piehl, Patrick,Elangovan, Saravanakumar,Neumann, Helfried,Beller, Matthias
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supporting information
p. 14967 - 14971
(2016/11/25)
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- Iron-Catalyzed α-Alkylation of Ketones with Alcohols
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A general and benign iron-catalyzed α-alkylation reaction of ketones with primary alcohols has been developed. The key to success of the reaction is the use of a Kn?lker-type complex as catalyst (2 mol %) in the presence of Cs2CO3 as base (10 mol %) under hydrogen-borrowing conditions. Using 2-aminobenzyl alcohol as alkylation reagent allows for the "green" synthesis of quinoline derivatives.
- Elangovan, Saravanakumar,Sortais, Jean-Baptiste,Beller, Matthias,Darcel, Christophe
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supporting information
p. 14483 - 14486
(2016/01/25)
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- Synthesis of a-Alkylated Ketones via Tandem Acceptorless Dehydrogenation/a-Alkylation from Secondary and Primary Alcohols Catalyzed by Metal-Ligand Bifunctional Iridium Complex [CpIr(2,2′-bpyO)(H2O)]
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A new strategy for the synthesis of α-alkylated ketones via tandem acceptorless dehydrogenation/α-alkylation from secondary and primary alcohols was proposed and accomplished. In the presence of metal-ligand bifunctional iridium complex [CpIr(2,2′-bpyO)(H2O)], various desirable products were obtained in high yields. Compared with previous methods for the direct dehydrogenative coupling of secondary alcohols with primary alcohols to α-alkylated ketones, this protocol has obvious advantages including complete selectivity for α-alkylated ketones and more environmentally benign conditions. Notably, the study also exhibited the potential to develop tandem reactions catalyzed using a metal-ligand bifunctional iridium complex.
- Wang, Rongzhou,Ma, Juan,Li, Feng
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p. 10769 - 10776
(2015/11/18)
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- Continuous flow synthesis of ketones from carbon dioxide and organolithium or grignard reagents
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We describe an efficient continuous flow synthesis of ketones from CO 2 and organolithium or Grignard reagents that exhibits significant advantages over conventional batch conditions in suppressing undesired symmetric ketone and tertiary alcohol byproducts. We observed an unprecedented solvent-dependence of the organolithium reactivity, the key factor in governing selectivity during the flow process. A facile, telescoped three-step-one-flow process for the preparation of ketones in a modular fashion through the in-line generation of organometallic reagents is also established.
- Wu, Jie,Yang, Xiaoqing,He, Zhi,Mao, Xianwen,Hatton, T. Alan,Jamison, Timothy F.
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supporting information
p. 8416 - 8420
(2014/08/18)
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- Iridium-CNP complex catalyzed cross-coupling of primary alcohols and secondary alcohols by a borrowing hydrogen strategy
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A highly efficient C-C bond formation has been developed through the cross-coupling of primary and secondary alcohols. The corresponding functionalized ketones were obtained with an iridium-CNP complex as a catalyst through the borrowing hydrogen strategy. The present methodology provides an easy alternative method to aldol reaction derivatives. More importantly, the complexes were also effective catalysts for the alkylation of an aromatic amine with a tertiary alkyl amine. This journal is
- Wang, Dawei,Zhao, Keyan,Yu, Xin,Miao, Hongyan,Ding, Yuqiang
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p. 42924 - 42929
(2015/02/19)
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- Direct α-alkylation of ketones with primary alcohols catalyzed by iridium-CNP complex
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The α-alkylation of ketones with primary alcohols was realized by CC cross-coupling with iridium-CNP complexes as catalyst. This reaction proceeds via dehydrogenation reactions, aldol condensation, and hydrogenation using the borrowed hydrogen atoms from alcohols. The pyridyl methanols and other heterocyclic substituted methanols, especially alkyl alcohols, were also suitable for this transformation.
- Wang, Dawei,Zhao, Keyan,Ma, Piming,Xu, Chongying,Ding, Yuqiang
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supporting information
p. 7233 - 7235
(2015/01/09)
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- An N-heterocyclic carbene-catalyzed approach to the indirect Friedl?nder quinoline synthesis
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Quinolines have been obtained through the indirect Friendl?nder annulation starting from 2-aminobenzyl alcohol or derivatives from it and ketones catalyzed by N-heterocyclic carbene, and the synthesis of polysubstituted quinolines through a one-pot, two-step tandem reaction starting from readily available ketones and alcohols via alpha-alkylation and indirect Friedl?nder annulation under air also has been presented.
- Zhu, Yanfang,Cai, Chun
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p. 52911 - 52914
(2015/02/05)
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- Catalyst-free dehydrative α-alkylation of ketones with alcohols: Green and selective autocatalyzed synthesis of alcohols and ketones
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Direct dehydrative α-alkylation reactions of ketones with alcohols are now realized under simple, practical, and green conditions without using external catalysts. These catalyst-free autocatalyzed alkylation methods can efficiently afford useful alkylated ketone or alcohol products in a one-pot manner and on a large scale by Ci£C bond formation of the in situ generated intermediates with subsequent controllable and selective Meerwein-Pondorf-Verley-Oppenauer-type redox processes. Plain and simple: The title reaction has been realized under simple and practical conditions without using external catalysts, and can afford alkylated ketone or alcohol products in a one-pot manner and on a large scale. The reaction proceeds by Ci£C bond formation of the in situ generated intermediates with subsequent controllable and selective Meerwein-Pondorf-Verley-Oppenauer-type redox processes. Copyright
- Xu, Qing,Chen, Jianhui,Tian, Haiwen,Yuan, Xueqin,Li, Shuangyan,Zhou, Chongkuan,Liu, Jianping
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p. 225 - 229
(2014/01/17)
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- Chemoselective transfer hydrogenation of α,β-unsaturated ketones catalyzed by pincer-Pd complexes using alcohol as a hydrogen source
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A pincer-Pd complex was utilized in the chemoselective transfer hydrogenation of α,β-unsaturated ketones using n-BuOH as a hydrogen source and solvent. Good to excellent yields were obtained for various substrates even with reducible groups. Based on deuterium-labeling experiments, the reaction mechanism is proposed to occur via a pincer-Pd-hydride intermediate.
- Ding, Boqiang,Zhang, Zhenfeng,Liu, Yangang,Sugiya, Masashi,Imamoto, Tsuneo,Zhang, Wanbin
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p. 3690 - 3693
(2013/08/23)
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- Aldehyde-catalyzed transition metal-free dehydrative β-alkylation of methyl carbinols with alcohols
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Different to the borrowing hydrogen strategy in which alcohols were activated by transition metal-catalyzed anaerobic dehydrogenation, the direct addition of aldehydes was found to be an effective but simpler way of alcohol activation that can lead to efficient and green aldehyde-catalyzed transition metal-free dehydrative C-alkylation of methyl carbinols with alcohols. Mechanistic studies revealed that the reaction proceeds via in situ formation of ketones by Oppenauer oxidation of the methyl carbinols by external aldehydes, aldol condensation, and Meerwein-Ponndorf-Verley (MPV)-type reduction of α,β-unsatutated ketones by substrate alcohols, affording the useful long chain alcohols and generating aldehydes and ketones as the by-products that will be recovered in the next condensation to finish the catalytic cycle. Copyright
- Xu, Qing,Chen, Jianhui,Liu, Quan
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p. 697 - 704
(2013/04/10)
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- Lithium tert-butoxide mediated α-alkylation of ketones with primary alcohols under transition-metal-free conditions
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LiOtBu was found to efficiently promote the α-alkylation reaction of ketones with primary alcohols, without the addition of any transition metal catalyst.
- Liang, Yu-Feng,Zhou, Xin-Feng,Tang, Shi-Ya,Huang, Yao-Bing,Feng, Yi-Si,Xu, Hua-Jian
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p. 7739 - 7742
(2013/06/27)
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- Palladium-Based Nanocatalyst for One-Pot Synthesis of Polysubstituted Quinolines
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The synthesis of quinolines has been achieved through a one-pot, two-step tandem reaction catalyzed with Ag-Pd alloy nanoparticles supported on carbon. Ag-Pd alloy nanoparticles catalyzed the coupling of a ketone with a primary alcohol through a hydrogen autotransfer process, which yields α-alkylated ketones under an Ar flow. These are reacted with 2-aminobenzyl alcohols in a modified Friedlaender synthesis to give polysubstituted quinolines in moderate to good yields.
- Chen, Benjamin Wei Jie,Chng, Leng Leng,Yang, Jun,Wei, Yifeng,Yang, Jinhua,Ying, Jackie Y.
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p. 277 - 283
(2013/03/13)
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- Iridium phosphine abnormal N-heterocyclic carbene complexes in catalytic hydrogen transfer reactions
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Several iridium complexes bearing chelating abnormal N-heterocyclic carbenes (NHCs) are shown to be active catalysts for transfer hydrogenation of ketones or enones, dehydrative C-C coupling between primary and secondary alcohols, and dehydrogenation of benzyl alcohol to benzyl benzoate. In the transfer hydrogenation of acetophenone, abnormal NHC complexes give higher activity than a normal analogue. Dehydrative C-C coupling reactions between primary and secondary alcohols result in β-alkylation of the secondary alcohols, using primary alcohols as the apparent alkylating reagents, and such reactions proceed with high yield and selectivity. These catalytic processes are known to involve metal-mediated temporary borrowing of hydrogen from alcohols and subsequent delivery of the hydrogen to CC and /or CO bonds.
- Gong, Xue,Zhang, Hong,Li, Xingwei
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supporting information; experimental part
p. 5596 - 5600
(2011/11/06)
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- Photochemically promoted transition metal-free cross-coupling of acylsilanes with organoboronic esters
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Intermolecular carbon-carbon bond formation between acylsilanes and organoboronic esters was achieved by photoirradiation under almost neutral, transition metal-free conditions. In this reaction, siloxycarbenes generated by photoisomerization of acylsilanes reacted with boronic esters to give the formal B-C bond insertion intermediates, which underwent unique rearrangement to afford the cyclic α-alkoxyboronic esters. Acidic treatment of the resulting crude products under air furnished the cross-coupled ketones in good yields.
- Ito, Kazuta,Tamashima, Hiroto,Iwasawa, Nobuharu,Kusama, Hiroyuki
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p. 3716 - 3719
(2011/05/14)
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- Direct acylation of aryl chlorides with aldehydes by palladium-pyrrolidine Co-catalysis
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A palladium catalyst system has been developed that allows for the direct acylation of aryl chlorides with aldehydes. The choice of ligand, as well as the presence of pyrrolidine and molecular sieves is shown to be critical to the catalysis, which appears to proceed via an enamine intermediate. The reaction was successful for a wide range of aryl chlorides and tolerant of functionality on the aldehyde component, giving easy access to alkyl aryl ketones in modest to good yields.
- Colbon, Paul,Ruan, Jiwu,Purdie, Mark,Xiao, Jianliang
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supporting information; experimental part
p. 3670 - 3673
(2010/10/20)
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- Alcohols for the α-alkylation of methyl ketones and indirect aza-wittig reaction promoted by nickel nanoparticles
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Nickel nanoparticles have been found to activate primary alcohols used for the α-alkylation of ketones or in indirect aza-Wittig reactions. These processes involve hydrogen transfer from the alcohol to the intermediate α,β-unsaturated ketone or imine, respectively. All these reactions are carried out in the absence of any ligand, hydrogen acceptor or base under mild reaction conditions. For the first time nickel is employed as a potential alternative to noble-metal-based catalysts in both reactions. A reaction mechanism is proposed on the basis of some deuteration experiments. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Alonso, Francisco,Riente, Paola,Yus, Miguel
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experimental part
p. 4908 - 4914
(2009/05/27)
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- The α-alkylation of methyl ketones with primary alcohols promoted by nickel nanoparticles under mild and ligandless conditions
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Nickel nanoparticles have been found to promote the α-alkylation of ketones with primary alcohols in the absence of any added ligand or base, under mild reaction conditions. Georg Thieme Verlag Stuttgart.
- Alonso, Francisco,Riente, Paola,Yus, Miguel
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p. 1877 - 1880
(2008/02/10)
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- Recyclable palladium catalyst for highly selective α alkylation of ketones with alcohols
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(Chemical Equation Presented) An air-stable, heterogeneous, and recyclable catalyst composed of palladium nanoparticles entrapped in aluminum hydroxide was applied to a highly selective α alkylation. A wide range of aliphatic and aromatic ketones and primary alcohols were coupled to prepare enones in an O2 atmosphere and ketones in an argon atmosphere (see scheme).
- Kwon, Min Serk,Kim, Namdu,Seo, Seong Hyeok,Park, In Soo,Cheedrala, Ravi Kumar,Park, Jaiwook
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p. 6913 - 6915
(2007/10/03)
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- Catalytic cross-coupling reaction of esters with organoboron compounds and decarbonylative reduction of esters with HCOONH4: A new route to acyl transition metal complexes through the cleavage of acyl-oxygen bonds in esters
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The Ru3(CO)12-catalyed cross-coupling reaction of esters with organoboron compounds leading to ketones is described. A wide variety of functional groups can be tolerated under the reaction conditions. Aromatic boronates function as a coupling partner to give aryl ketones. Acyl-alkyl coupling to dialkyl ketones is also achieved by the use of 9-alkyl-9-BBN in place of boronates. The Ru3(CO)12- catalyzed decarbonylative reduction of esters with ammonium formate (HCOONH 4) leading to hydrocarbons is also described. No expected aldehydes are produced, and controlled experiments indicate that aldehydes are not intermediate for the transformation. A hydrosilane can also be used as a reducing reagent in place of HCOONH4. A wide variety of functional groups are compatible for both reactions. The key step for both catalytic reactions is the directing group-promoted cleavage of an acyl carbon-oxygen bond in esters, leading to the generation of acyl transition metal alkoxo complexes.
- Tatamidani, Hiroto,Yokota, Kazuhiko,Kakiuchi, Fumitoshi,Chatani, Naoto
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p. 5615 - 5621
(2007/10/03)
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