- Preparation of Primary and Secondary Dialkylmagnesiums by a Radical I/Mg-Exchange Reaction Using sBu2Mg in Toluene
-
The treatment of primary or secondary alkyl iodides with sBu2Mg in toluene (25–40 °C, 2–4 h) provided dialkylmagnesiums that underwent various reactions with aldehydes, ketones, acid chlorides or allylic bromides. 3-Substituted secondary cyclohexyl iodides led to all-cis-3-cyclohexylmagnesium reagents under these exchange conditions in a highly stereoconvergent manner. Enantiomerically enriched 3-silyloxy-substituted secondary alkyl iodides gave after an exchange reaction with sBu2Mg stereodefined dialkylmagnesiums that after quenching with various electrophiles furnished various 1,3-stereodefined products including homo-aldol products (99 % dr and 98 % ee). Mechanistic studies confirmed a radical pathway for these new iodine/magnesium-exchange reactions.
- Knochel, Paul,Lutter, Ferdinand H.,Sunagatullina, Alisa S.
-
supporting information
(2022/02/16)
-
- Visible-Spectrum Solar-Light-Mediated Benzylic C-H Oxygenation Using 9,10-Dibromoanthracene As an Initiator
-
We report a visible-light-mediated benzylic C-H oxygenation reaction. The reaction is initiated by solar light or the blue LED activation of 9,10-dibromoanthracene in a reaction with oxygen and takes place at ambient temperature and air pressure. Secondary benzylic positions are oxygenated to ketones, while tertiary benzylic carbons are oxygenated to give hydroperoxides. Notably, cumene hydroperoxide is produced in a higher yield and at milder conditions than the currently employed industrial conditions.
- Santra, Sourav K.,Szpilman, Alex M.
-
p. 1164 - 1171
(2020/12/23)
-
- LIGHT INDUCED CATALYTIC C-H OXYGENATION OF ALKANES
-
A method of oxygenating a benzylic C-H bond is provided. The method comprises light induced activation of an initiator and subsequent reaction with oxygen, resulting in the formation of free radicals. Subsequently, free radicals catalyze the reaction of the benzylic C-H bond with oxygen, thereby forming an oxygenated compound.
- -
-
Paragraph 00219
(2021/04/02)
-
- Synthesis of α-Alkylated Ketones via Selective Epoxide Opening/Alkylation Reactions with Primary Alcohols
-
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
-
supporting information
p. 5229 - 5234
(2021/07/19)
-
- Ir(NHC)-Catalyzed Synthesis of β-Alkylated Alcohols via Borrowing Hydrogen Strategy: Influence of Bimetallic Structure
-
Multi N-heterocyclic carbene(NHC)-modified iridium catalysts were employed in the β-alkylation of alcohols; dimerization of primary alcohols (Guerbet reaction), cross-coupling of secondary and primary alcohols, and intramolecular cyclization of alcohols. Mechanistic studies of Guerbet reaction, including kinetic experiments, mass analysis, and density functional theory (DFT) calculation, were employed to explain the fast reaction promoted by bimetallic catalysts, and the dramatic reactivity increase of monometallic catalysts at the late stage of the reaction. (Figure presented.).
- Sung, Kihyuk,Lee, Mi-hyun,Cheong, Yeon-Joo,Kim, Yu Kwon,Yu, Sungju,Jang, Hye-Young
-
supporting information
p. 3090 - 3097
(2021/05/10)
-
- Synthesis and catalytic applications of Ru and Ir complexes containing N,O-chelating ligand
-
A series of monometallic complexes (Ru1–3, Ir1–3) which have N,O-chelating ligand (pyrazine-2-carboxylate (1), pyridine-2-carboxylate (2), quinoline carboxylate(3) and bimetallic complexes (Ru4,5, Ir4,5) bridged by pyrazine-2,3- dicarboxylate (4) and imidazole-4,5-dicarboxylate(5) were synthesized and characterized by 1H-, 13C NMR, FT-IR, and elemental analysis. The crystal structure of Ir2 was determined by X-ray crystallography. The complexes (Ru1–5, Ir1–5) were applied to investigate the electronic and steric effect of ligand in their catalytic activities in transfer hydrogenation and alpha(α)-alkylation reaction of ketones with alcohols. The activities of iridium complexes (Ir1–5) were much more efficient than ruthenium complexes (Ru1–5). The highest activity for both reactions was observed for the complex (Ir2) with pyridine-2-carboxylate. The Ir hydride species was monitored for both reactions.
- Pakyapan, Bilge,Kavukcu, Serdar Bat?kan,?ahin, Zarife Sibel,Türkmen, Hayati
-
-
- C-C coupling formation using nitron complexes
-
A series of RuII (1), RhIII (2), IrIII (3, 4), IrI (5) and PdII (6-9) complexes of the 'instant carbene' nitron were prepared and characterized by 1H- and 13C-NMR, FT-IR and elemental analysis. The molecular structures of complexes 1-4 and 6 were determined by X-ray diffraction studies. The catalytic activity of the complexes (1-9) was evaluated in alpha(α)-alkylation reactions of ketones with alcohol via the borrowing hydrogen strategy under mild conditions. These complexes were able to perform this catalytic transformation in a short time with low catalyst and base amounts under an air atmosphere. Also, the PdII-nitron complexes (6-9) were applied in the Suzuki-Miyaura C-C coupling reaction and these complexes successfully initiated this reaction in a short time (30 minutes) using the H2O/2-propanol (1.5?:?0.5) solvent system. The DFT calculations revealed that the Pd0/II/0 pathway was more preferable for the mechanism
- Sevim, Mehmet,Kavukcu, Serdar Batikan,Kinal, Arma?an,?ahin, Onur,Türkmen, Hayati
-
supporting information
p. 16903 - 16915
(2020/12/18)
-
- Piano-stool Ru (II) arene complexes that contain ethylenediamine and application in alpha-alkylation reaction of ketones with alcohols
-
A series of piano-stool Ru (II) complexes (Ru1–7) bearing ethylenediamine with aryl and aliphatic groups were prepared and fully characterized by 1H, 13C, 19F and 31P NMR spectroscopy, FT-IR and elemental analysis. The crystal structures of Ru2–4 and Ru7 were determined by X-ray crystallography. They were successfully applied to the alpha(α)-alkylation of aliphatic and aromatic ketones with alcohols via the borrowing hydrogen strategy in mild reaction conditions within a short time. The catalytic system has a broad substrate scope, which allows the synthesis of alpha alkylated ketones with excellent yields. The electronic and steric effects of complexes on catalytic activity were analysed. The influence of the carbon chain length of the ligand on the alpha-alkylation reaction of ketones was also investigated. The catalytic cycle was also examined by 1H-NMR spectroscopy in d8-toluene.
- Kavukcu, Serdar Bat?kan,Günnaz, Salih,?ahin, Onur,Türkmen, Hayati
-
-
- Nickel-Catalyzed Alkylation of Ketone Enolates: Synthesis of Monoselective Linear Ketones
-
Herein we have developed a Ni-catalyzed protocol for the synthesis of linear ketones. Aryl, alkyl, and heteroaryl ketones as well as alcohols yielded the monoselective ketones in up to 90% yield. The catalytic protocol was successfully applied in to a gram-scale synthesis. For a practical utility, applications of a steroid derivative, oleyl alcohol, and naproxen alcohol were employed. Preliminary catalytic investigations involving the isolation of a Ni intermediate and defined Ni-H species as well as a series of deuterium-labeling experiments were performed.
- Das, Jagadish,Vellakkaran, Mari,Banerjee, Debasis
-
p. 769 - 779
(2019/01/24)
-
- Palladium on carbon-catalyzed Α-alkylation of ketones with alcohols as electrophiles: Scope and mechanism
-
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
-
p. 153 - 160
(2019/02/14)
-
- Stereodivergent synthesis of alkenes by controllable syn-/anti-fragmentation of β-hydroxysulfonyl intermediates
-
The reduction of the carbonyl group in acylated trifluoroethyl alkanesulfonates follows the Felkin-Ahn selectivity, and the so-formed diastereomeric β-hydroxysulfonyl intermediates undergo syn- and anti-fragmentation, depending on the reaction conditions. In effect, isomeric E- and Z-alkenes are formed in a stereodivergent manner, which mimics the mechanistic manifold of the Peterson olefination.
- Górski, Bartosz,Basiak, Dariusz,Grzesiński, ?ukasz,Barbasiewicz, Micha?
-
supporting information
p. 7660 - 7663
(2019/08/30)
-
- C?C Bond Formation of Benzyl Alcohols and Alkynes Using a Catalytic Amount of KOtBu: Unusual Regioselectivity through a Radical Mechanism
-
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
-
supporting information
p. 3373 - 3377
(2019/02/14)
-
- Ligand-Controlled Chemoselective C(acyl)-O Bond vs C(aryl)-C Bond Activation of Aromatic Esters in Nickel Catalyzed C(sp2)-C(sp3) Cross-Couplings
-
A ligand-controlled and site-selective nickel catalyzed Suzuki-Miyaura cross-coupling reaction with aromatic esters and alkyl organoboron reagents as coupling partners was developed. This methodology provides a facile route for C(sp2)-C(sp3) bond formation in a straightforward fashion by successful suppression of the undesired β-hydride elimination process. By simply switching the phosphorus ligand, the ester substrates are converted into the alkylated arenes and ketone products, respectively. The utility of this newly developed protocol was demonstrated by its wide substrate scope, broad functional group tolerance and application in the synthesis of key intermediates for the synthesis of bioactive compounds. DFT studies on the oxidative addition step helped rationalizing this intriguing reaction chemoselectivity: whereas nickel complexes with bidentate ligands favor the C(aryl)-C bond cleavage in the oxidative addition step leading to the alkylated product via a decarbonylative process, nickel complexes with monodentate phosphorus ligands favor activation of the C(acyl)-O bond, which later generates the ketone product.
- Chatupheeraphat, Adisak,Liao, Hsuan-Hung,Srimontree, Watchara,Guo, Lin,Minenkov, Yury,Poater, Albert,Cavallo, Luigi,Rueping, Magnus
-
p. 3724 - 3735
(2018/03/21)
-
- Cross-dehydrogenative coupling strategy for phosphonation and cyanation of secondary N-alkyl anilines by employing 2,3-dichloro-5,6-dicyanobenzoquinone
-
The cross-dehydrogenative coupling strategy for metal-free phosphonation and cyanation of secondary N-alkyl anilines has been developed firstly under mild reaction conditions. Based on detailed optimization of reaction conditions, the substrate generality of N-alkyl anilines and various hydrogen phosphonates has been investigated, and a series of versatile α-aminophosphonates and α-aminonitriles were therefore furnished in good to excellent yields. A plausible collective reaction mechanism through dehydrogenation to imine formation, then to respective α-aminophosphonates and α-aminonitriles was proposed.
- Liu, Qing,Yu, Shuchen,Hu, Liangzhen,Hussain, Muhamad Ijaz,Zhang, Xiaohui,Xiong, Yan
-
p. 7209 - 7217
(2018/11/10)
-
- Iridium(I)-Catalyzed Alkylation Reactions to Form α-Alkylated Ketones
-
A highly effective and green procedure for the formation of α-alkylated ketones has been disclosed via the reaction of primary alcohols with secondary alcohols and ketones by using [IrCl(COD)(NHC)] complexes as a catalyst. Various α-alkylated ketones were obtained in high yields from the alkylation of alcohol with alcohol and ketone with alcohol through a borrowing hydrogen reaction by using 0.05-0.5 mol % iridium(I) and a catalytic amount of KOH (5-10 mol %) as the base under air atmosphere and within very short reaction times.
- Gen?, Serta?,Günnaz, Salih,?etinkaya, Bekir,Gülcemal, Süleyman,Gülcemal, Derya
-
p. 2875 - 2881
(2018/03/09)
-
- Resolving a Reactive Organometallic Intermediate from Dynamic Directing Group Systems by Selective C?H Activation
-
Catalyst discovery from systems of potential precursors is a challenging endeavor. Herein, a new strategy applying dynamic chemistry to the identification of catalyst precursors from C?H activation of imines is proposed and evaluated. Using hydroacylation of imines as a model reaction, the selection of an organometallic reactive intermediate from a dynamic imine system, involving many potential directing group/metal entities, is demonstrated. The identity of the amplified reaction intermediate with the best directing group could be resolved in situ by ESI-MS, and coupling of the procedure to an iterative deconvolution protocol generated a system with high screening efficiency.
- Schaufelberger, Fredrik,Timmer, Brian J. J.,Ramstr?m, Olof
-
supporting information
p. 101 - 104
(2018/01/08)
-
- Palladium and visible-light mediated carbonylative Suzuki-Miyaura coupling of unactivated alkyl halides and aryl boronic acids
-
Herein, a simple and efficient method for the palladium-catalyzed carbonylation of aryl boronic acids with unactivated alkyl iodides and bromides under visible-light irradiation, ambient temperature and low CO-pressure is presented. Notably, the procedure uses readily available equipment and an inexpensive palladium catalyst to generate the key alkyl radical intermediate. These mild conditions enabled the synthesis of a range of functionalized aryl alkyl ketones including the antipsychotic drug, melperone.
- Roslin, Sara,Odell, Luke R.
-
supporting information
p. 6895 - 6898
(2017/07/10)
-
- Iron-Catalyzed Radical Decarboxylative Oxyalkylation of Terminal Alkynes with Alkyl Peroxides
-
An iron-catalyzed oxyalkylation of alkynes with alkyl peroxides as the alkylating reagents has been investigated. Alkyl peroxides are readily available from aliphatic acids and serve simultaneously as the alkylating reagents and internal oxidants. Primary, secondary, and tertiary alkyl groups of aliphatic acids were readily incorporated into C?C triple bonds and diverse α-alkylated ketones were synthesized. Mechanism studies revealed that this reaction involves highly reactive alkyl free radicals. A unique equilibrium between lauric acid and water catalyzed by the iron(III) catalyst was observed.
- Zhu, Xiaotao,Ye, Changqing,Li, Yajun,Bao, Hongli
-
supporting information
p. 10254 - 10258
(2017/08/07)
-
- Sodium Bromide-Catalyzed Oxidation of Secondary Benzylic Alcohols Using Aqueous Hydrogen Peroxide as Terminal Oxidant
-
A halide salt, hydroperoxide and AcOH catalyst system was applied to the oxidation of secondary benzylic alcohols. This simple system can be applied to a variety of secondary benzylic alcohols and scaled up for gram-scale preparation. High secondary benzylic alcohol selectivity of the present method is demonstrated in hydroxyketone synthesis. Based on several experimental results, a catalytic cycle for our oxidation is proposed.
- Komagawa, Hiromi,Maejima, Yukako,Nagano, Takashi
-
p. 789 - 793
(2016/03/09)
-
- A base-controlled chemoselective transfer hydrogenation of α,β-unsaturated ketones catalyzed by [IrCpCl2]2 with 2-propanol
-
A simple homogeneous catalyst system based on commercially available [IrCpCl2]2 has been developed for the conjugate reduction of α,β-unsaturated ketones. Under the optimized conditions, a wide range of α,β-unsaturated ketones were reduced to saturated ketones in 83-98% yield. While switching the base from K2CO3 to KOH, saturated alcohols was selectively obtained.
- Chen, Shu-Jie,Lu, Guo-Ping,Cai, Chun
-
p. 13208 - 13211
(2015/03/05)
-
- Wool supported manganese dioxide nano-scale dispersion: A biopolymer based catalyst for the aerobic oxidation of organic compounds
-
A wool supported manganese dioxide nano-scale dispersion (MnO2@wool) was synthesized by soaking wool in a potassium permanganate solution and characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The synthesized catalyst, MnO2@wool complex, has been found to be able to catalyze the selective aerobic oxidation of alkyl arenes, alcohols, oximes, and sulfides to their corresponding carbonyl and sulfoxide compounds in the absence of additional oxidizing reagent. The selective conversion of thiols to disulfides was carried on by this biopolymer based supported catalyst, too.
- Shaabani, Ahmad,Hezarkhani, Zeinab,Badali, Elham
-
p. 61759 - 61767
(2015/08/03)
-
- Cobalt-catalyzed intermolecular hydroacylation of olefins through chelation-assisted imidoyl C-H activation
-
A low-valent cobalt catalyst generated from cobalt(II) bromide, a diphosphine ligand, and zinc powder promotes intermolecular hydroacylation of olefins using N-3-picolin-2-yl aldimines as aldehyde equivalents, which affords, upon acidic hydrolysis, ketone products in moderate to good yields with high linear selectivity. The reaction is applicable to styrenes, vinylsilanes, and aliphatic olefins as well as to various aryl and heteroaryl aldimines. The cobalt catalysis features a distinctively lower reaction temperature (60 °C) compared with those required for the same type of transformations catalyzed by rhodium complexes (typically 130-150°C).
- Yang, Junfeng,Seto, Yuan Wah,Yoshikai, Naohiko
-
p. 3054 - 3057
(2015/05/20)
-
- Oxidation of alcohols to aldehydes or ketones with 1-acetoxy-1,2- benziodoxole-3(1H)-one derivatives
-
Various benzylic and aliphatic alcohols were smoothly oxidized to the corresponding aromatic aldehydes and ketones as well as aliphatic ketones by treatment with 1-acetoxy-5-nitro-1,2-benziodoxole-3(1H)-one (ANBX), 1-acetoxy-5-bromo-1,2-benziodoxole-3(1H)-one (ABBX), 1-acetoxy-5-chloro-1,2- benziodoxole-3(1H)-one (ACBX), and 1-acetoxy-5-fluoro-1,2-benziodoxole-3(1H)-one (AFBX). These new tri-valent iodine compounds were prepared from 5-substituted 2-iodobenzoic acids and meta-chloroperoxybenzoic acid (m-CPBA). ANBX and ABBX were the most effective reagents for this oxidation of alcohols, and this present reaction is very attractive because of the ease of product isolation and the reusability of the reagents.
- Iinuma, Masataka,Moriyama, Katsuhiko,Togo, Hideo
-
p. 772 - 780
(2014/03/21)
-
- Oxidation of Alcohols to Aldehydes or Ketones with 1-Acetoxy-1,2-benziodoxole-3(1H)-one Derivatives
-
Various benzylic and aliphatic alcohols were smoothly oxidized to the corresponding aromatic aldehydes and ketones as well as aliphatic ketones by treatment with 1-acetoxy-5-nitro-1,2-benziodoxole-3(1H)-one (ANBX), 1-acetoxy-5-bromo-1,2-benziodoxole-3(1H)-one (ABBX), 1-acetoxy-5-chloro-1,2-benziodoxole-3(1H)-one (ACBX), and 1-acetoxy-5-fluoro-1,2-benziodoxole-3(1H)-one (AFBX). These new trivalent iodine compounds were prepared from 5-substituted 2-iodobenzoic acids and meta-chloroperoxybenzoic acid (m-CPBA). ANBX and ABBX were the most effective reagents for this oxidation of alcohols, and this present reaction is very attractive because of the ease of product isolation and the reusability of the reagents.
- Iinuma, Masataka,Moriyama, Katsuhiko,Togo, Hideo
-
p. 772 - 780
(2015/10/05)
-
- Coenzyme-inspired chemistry 2: 4,5-dihydroimidazolium ylides (NHCs) and the reactions of 2-(1-hydroxyalkyl)-4,5-dihydroimidazoles
-
Ketones are prepared from aldehydes via 1-benzyl-2-(1-hydroxyalkyl)-4,5- dihydroimidazoles (adducts of the aldehydes with 1-benzyl-2-lithio-4,5- dihydroimidazoles) whereas 1-benzyl-2-(1-oxoalkyl)-4,5-dihydroimidazoles are shown to act as acyl transfer reagents via C-C bond cleavage. 4,5-Dihydroimidazolium ylides (NHCs) are intermediates in both processes, which constitute thiamine-inspired C-C bond formation and cleavage protocols.
- Jones, Raymond C. F.,Nichols, John R.
-
p. 5926 - 5935
(2013/09/12)
-
- Synthesis of alkyl aryl ketones by Pd/light induced carbonylative cross-coupling of alkyl iodides and arylboronic acids
-
Alkyl aryl ketones were synthesized by the carbonylative cross-coupling reaction of alkyl iodides and arylboronic acids under combined Pd/light conditions. In this reaction, it is likely that an acylpalladium species would be formed via carbonylation of t
- Sumino, Shuhei,Ui, Takahito,Ryu, Ilhyong
-
p. 3142 - 3145
(2013/07/26)
-
- Clean borrowing hydrogen methodology using hydrotalcite supported copper catalyst
-
The catalytic activity of Mg-Al hydrotalcite supported copper catalyst was investigated for clean CC and CN bond forming reactions using alcohols as alkylating agent via borrowing hydrogen methodology. The catalyst showed excellent conversion of ketone and amine substrates (71-99%) to alkylated products with high selectivity in alkylation reactions.
- Dixit, Manish,Mishra, Manish,Joshi, Pradyuman A.,Shah, Dinesh O.
-
-
- Traceless chelation-controlled rhodium-catalyzed intermolecular alkene and alkyne hydroacylation
-
A new functional-group tolerant, rhodium-catalyzed, sulfide-reduction process is combined with rhodium-catalyzed chelation-controlled hydroacylation reactions to give a traceless hydroacylation protocol. Aryl- and alkenyl aldehydes can be combined with both alkenes, alkynes and allenes to give traceless products in high yields. A preliminary mechanistic proposal is also presented. Traceless catalysis: The powerful combination of a chelation-controlled hydroacylation process and a new rhodium-catalyzed sulfide reduction gave the products of traceless hydroacylation. Aryl- and alkenyl aldehydes can be combined with alkenes, alkynes, and allenes to deliver traceless products in high yields (see scheme). Copyright
- Hooper, Joel F.,Young, Rowan D.,Weller, Andrew S.,Willis, Michael C.
-
supporting information
p. 3125 - 3130
(2013/03/28)
-
- Facile oxidation of alcohols to aldehydes or ketones with 1-acetoxy-5-nitro-1,2-benziodoxole-3(1 H)-one
-
Various benzylic alcohols and aliphatic secondary alcohols were smoothly oxidized to the corresponding aromatic aldehydes, aromatic ketones, and aliphatic ketones, respectively, with the novel 1-acetoxy-5-nitro-1,2- benziodoxole-3(1H)-one (ANBX) alone, a trivalent iodine prepared from the oxidation of 2-iodo-5-nitrobenzoic acid with MCPBA. The present reaction is the first effective method for the oxidation of alcohols with a trivalent iodine alone under mild reaction conditions. Georg Thieme Verlag Stuttgart New York.
- Iinuma, Masataka,Moriyama, Katsuhiko,Togo, Hideo
-
p. 1707 - 1711
(2013/09/02)
-
- Preparation of alkylmagnesium reagents from alkenes through hydroboration and boron-magnesium exchange
-
Tolerant: Alkylmagnesium reagents can be synthesized from alkenes through a sequence of hydroboration and subsequent boron-magnesium exchange using a method that tolerates different functional groups (see scheme). The resulting alkylmagnesium reagents can be used in carbon-carbon bond forming reactions, such as alkylation reactions or transition-metal-catalyzed cross-coupling reactions. Copyright
- Reichle, Markus A.,Breit, Bernhard
-
supporting information; experimental part
p. 5730 - 5734
(2012/08/14)
-
- Rhodium-phosphoramidite catalyzed alkene hydroacylation: Mechanism and octaketide natural product synthesis
-
We describe a method that allows salicylaldehyde derivatives to be coupled with a wide range of unactivated alkenes at catalyst loadings as low as 2 mol %. A chiral phosphoramidite ligand and the precise stoichiometry of heterogeneous base are key for high catalytic activity and linear regioselectivity. This protocol was applied in the atom- and step-economical synthesis of eight biologically active octaketide natural products, including anticancer drug candidate cytosporone B. Mechanistic studies provide insight on parameters affecting decarbonylation, a side reaction that limits the turnover number for catalytic hydroacylation. Deuterium labeling studies show that branched hydride insertion is fully reversible, whereas linear hydride insertion is largely irreversible and turnover-limiting. We propose that ligand (R a,R,R)-SIPHOS-PE effectively suppresses decarbonylation, and helps favor a turnover-limiting insertion, by lowering the barrier for reductive elimination in the linear-selective pathway. Together, these factors enable high reactivity and regioselectivity.
- Von Delius, Max,Le, Christine M.,Dong, Vy M.
-
p. 15022 - 15032
(2012/11/06)
-
- Synthesis, insecticidal evaluation of novel 1,3,4-thiadiazole chrysanthemamide derivatives formed by an EDCI/HOBt condensation
-
A series of novel pesticides with two components derived from a 1,3,4-thiadiazole and chrysanthemic acid were synthesised via an EDCI/HOBt condensation. These 1,3,4-thiadiazole chrysanthemamides were identified by IR, 1H NMR and elemental analyses. Their insecticidal activity was also evaluated.
- Yu, Peng,Hu, Jun,Zhou, Tao-Yu,Wang, Peng,Xu, Yan-Hua
-
experimental part
p. 703 - 706
(2012/03/10)
-
- Iridium phosphine abnormal N-heterocyclic carbene complexes in catalytic hydrogen transfer reactions
-
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
-
p. 5596 - 5600
(2011/11/06)
-
- Inter- and intramolecular hydroacylation of alkenes employing a bifunctional catalyst system
-
Based on a conceptually innovative bifunctional P,N ligand, an efficient protocol for the rhodium-catalyzed inter- and intramolecular hydroacylation of alkenes has been developed.
- Vautravers, Nicolas R.,Regent, Damien D.,Breit, Bernhard
-
supporting information; experimental part
p. 6635 - 6637
(2011/06/27)
-
- One-pot catalytic C-C double bond cleavage of α,β-enones aided by alkyl group-immobilized silica spheres
-
Catalytic C-C double bond cleavage of α,β-enones with a 1-alkene and H2O was carried out in the presence of a (Ph3P)3RhCl catalyst, 2-amino-3-picoline, cyclohexylamine, benzoic acid, and alkyl group-immobilized silica spheres. Upon completion of the reaction, the corresponding ketones were obtained without needing a further hydrolysis step. In this reaction, alkyl group-immobilized silica spheres act as a water reservoir for hydrolysis of an intermediate ketimine and as a phase divider between the organic solution and H2O.
- Lee, Dong Hun,Jo, Eun-Ae,Park, Jung-Woo,Jun, Chul-Ho
-
experimental part
p. 160 - 163
(2010/03/04)
-
- Liquid-crystalline polymorphism of symmetrical azobananas: Bis(4-(4-alkylphenyl)azophenyl) 2-nitroisophtalates
-
In this paper we present a series of novel compounds, bis(4-(4-alkylphenyl) azophenyl) 2-nitroisophtalates, which exhibit nematic and banana-type liquidcrystalline phases. The alkyl chain length varies from 1 to 18 carbons. The first ten members of this series exhibit nematic phase. The last eleven compounds exhibit banana-type liquid crystalline phases. The propyl and pentyl derivatives have extra second type of banana mesophase. Copyright Taylor & Francis Group, LLC.
- Zygadlo,Dardas,Nowicka,Hofmann,Galewski
-
scheme or table
p. 283 - 291
(2011/08/02)
-
- PhI- and polymer-supported PhI-catalyzed oxidative conversion of ketones and alcohols to α-tosyloxyketones with m-chloroperbenzoic acid and p-toluenesulfonic acid
-
Various ketones were converted to the corresponding α-tosyloxyketones with mCPBA and p-toluenesulfonic acid in the presence of a catalytic amount of iodobenzene. Moreover, secondary alcohols were directly converted to the corresponding α-tosyloxyketones using mCPBA and catalytic amounts of iodobenzene and potassium bromide, followed by treatment with p-toluenesulfonic acid in a one-pot manner. Poly(4-iodostyrene) could be also used as a recyclable catalyst for the same α-tosyloxylation of ketone.
- Yamamoto, Yukiharu,Kawano, Yuhta,Toy, Patrick H.,Togo, Hideo
-
p. 4680 - 4687
(2007/10/03)
-
- Efficient synthesis of functionalized organozinc compounds by the direct insertion of zinc into organic iodides and bromides
-
(Chemical Equation Presented) Insider dealing: A wide range of poly-functional (hetero)aromatic and aliphatic zinc reagents can be easily prepared in THF. The compounds are formed by a Zn insertion reaction mediated by the addition of LiCl (see scheme; All = allyl).
- Krasovskiy, Arkady,Malakhov, Vladimir,Gavryushin, Andrei,Knochel, Paul
-
p. 6040 - 6044
(2007/10/03)
-
- Facile oxidative conversion of alcohols to esters using molecular iodine
-
A simple, efficient, and high-yield procedure for the oxidative conversion of alcohols to various types of esters and ketones, with molecular iodine and potassium carbonate was successfully carried out.
- Mori, Naoshi,Togo, Hideo
-
p. 5915 - 5925
(2007/10/03)
-
- A New Solvent System for Recycling Catalysts for Chelation-Assisted Hydroacylation of Olefins with Primary Alcohols
-
A new method to separate and reuse the catalyst system consisting of a rhodium complex and 2-aminopyridines for chelation-assisted hydroacylation was achieved using phenol and 4,4′-dipyridyl as the reaction medium, and 4-diphenylphosphinobenzoic acid as a ligand. Copyright
- Chang, Duck-Ho,Lee, Dae-Yon,Hong, Boo-Sun,Choi, Jun-Hack,Jun, Chul-Ho
-
p. 424 - 425
(2007/10/03)
-
- Palladium-Catalyzed Cross-Coupling Reactions of Carboxylic Anhydrides with Organozinc Reagents
-
(Matrix presented) Negishi-type cross-coupling reaction was effected by employing organozincs and anhydrides or mixed anhydrides that formed in situ from sodium salts of the corresponding acids and ethyl chloroformate under the catalysis of palladium(0). A general method for preparing symmetrical/ unsymmetrical ketones was developed.
- Wang, Donghui,Zhang, Zhaoguo
-
p. 4645 - 4648
(2007/10/03)
-
- Montmorillonite K10 as a suitable co-catalyst for atom economy in chelation-assisted intermolecular hydroacylation
-
The clay montmorillonite K10 is an efficient acidic solid that can act as a reusable co-catalyst in the condensation reaction of aldehydes and amines to provide the imine intermediate which is then transformed into the ketone through the hydroiminoacylation reaction, in the presence of rhodium complexes.
- Ya?ez, Xiomara,Claver, Carmen,Castillon, Sergio,Fernandez, Elena
-
p. 1631 - 1634
(2007/10/03)
-
- Palladium-catalyzed coupling reaction of acylzirconocene chlorides with hypervalent iodonium salts: Synthesis of aryl-substituted ketones
-
The palladium-catalyzed acylation reaction of alkenoyl- and alkanoylzirconocene chlorides with hypervalent iodonium salts afforded the acylated aromatic compounds under mild conditions.
- Kang, Suk-Ku,Yoon, Seok-Keun
-
p. 459 - 461
(2007/10/03)
-
- Solvent-free chelation-assisted hydroacylation of olefin by rhodium(I) catalyst under microwave irradiation
-
A solvent-free protocol for the rhodium(I)-catalyzed intermolecular hydroacylation was achieved under microwave irradiation to furnish various ketones in high yields. The reactivity was improved by the addition of aniline as well as 2-amino-3-picoline and benzoic acid to induce a transimination, which facilitates the formation of intermediate aldimine. A comparison of the reactivity between the reaction performed under the conventional heating mode and the microwave irradiation using monomode reactor revealed an important specific microwave effect during the chelation-assisted hydroacylation. It is supposed that the observed specific microwave effect mainly originates from the formation of aldimine by condensation of aldehyde and amine, which leads to a development of charges in the transition state. This result confirms that the rate-determining step of the reaction is the initial condensation step rather than the subsequent hydroiminoacylation step.
- Loupy, Andre,Chatti, Saber,Delamare, Sarah,Lee, Dae-Yon,Chung, Jong-Hwa,Jun, Chul-Ho
-
p. 1280 - 1285
(2007/10/03)
-
- Nickel-catalyzed cross-coupling between functionalized primary or secondary alkylzinc halides and primary alkyl halides
-
In the presence of Bu4NI (3 equiv) and 4-fluorostyrene (20 mol %), unreactive primary and secondary alkylzinc iodides undergo nickel-catalyzed cross-couplings with various primary alkyl iodides or bromides. More reactive secondary dialkylzincs and the mixed zinc organometallics RZnTMSM undergo the cross-coupling reaction in the absence of Bu4NI. The bicyclic secondary diorganozinc 6 prepared via boron-zinc exchange reacts with high retention of configuration. Free NH-groups are tolerated in the cross-coupling allowing the synthesis of aminated products.
- Jensen, Anne Eeg,Knochel, Paul
-
-
- Nickel catalysed electrosynthesis of ketones from organic halides and iron pentacarbonyl. Part 2: Unsymmetrical ketones
-
Unsymmetrical aryl-benzyl or aryl-alkyl ketones are obtained by electrolysing in an undivided cell a DMF solution containing two organic halides, iron pentacarbonyl and a catalytic amount of a nickel-2,2′-bipyridine complex.
- Dolhem, Eric,Barhdadi, Rachid,Folest, Jean Claude,Nédelec, Jean Yves,Troupel, Michel
-
p. 525 - 529
(2007/10/03)
-
- The radical-chain addition of aldehydes to alkenes by the use of N-hydroxyphthalimide (NHPI) as a polarity-reversal catalyst
-
Hydroacylation of simple alkenes with aldehydes via a radical process was successfully achieved by the use of N-hydroxyphthalimide (NHPI) as a polarity-reversal catalyst. Thus, 5-tridecanone was obtained by the reaction of oct-1-ene with pentanal in the presence of small amounts of NHPI and dibenzoyl peroxide (BPO).
- Tsujimoto,Iwahama,Sakaguchi,Ishii
-
p. 2352 - 2353
(2007/10/03)
-
- New efficient nickel-catalyzed cross-coupling reaction between two Csp3 centers
-
The presence of a remote unsaturation (double bond, carbonyl group, cyano group) in an alkyl halide facilitates its cross-coupling reaction with various diorganozincs in the presence of Ni(acac)2 (7.5-10 mol % in THF/NMP mixtures). These results were used to develop a new general cross-coupling reaction between functionalized diorganozincs and alkyl iodides using m- or p-trifluoromethylstyrene as a reaction promotor and Ni(acac)2 as a catalyst (7.5-10 mol %; -35 °C, 5-10 h) leading to a broad range of polyfunctional cross-coupling products.
- Giovannini,Strudemann,Devasagayaraj,Dussin,Knochel
-
p. 3544 - 3553
(2007/10/03)
-
- Catalytic transformation of aldimine to ketimine by Wilkinson's complex through transimination
-
(equation presented) The C-H bond activation in homogeneous catalysis is important for carbon skeleton construction through C-C bond formation. In this report, a new direct synthesis of ketimine from aldimine bearing no coordination site is demonstrated with high catalytic efficiency. Transimination is the major role for this catalytic reaction.
- Jun, Chul-Ho,Hong, Jun-Bae
-
p. 887 - 889
(2008/02/10)
-