- Lithiation of aryl bromides possessing α-proton of carbonyl groups
-
A new methodology for metalation of aryl bromide possessing an active methylene adjacent to carbonyl groups is described. In order to avoid self-quenching, selective deprotonation was necessary prior to halogen-metal exchange reaction. For this purpose, m
- Yamamoto, Yuhei,Maeda, Kenji,Tomimoto, Koji,Mase, Toshiaki
-
-
Read Online
- Development of a Triazine-Based tert-Butylating Reagent, TriAT-tBu
-
A new tert-butylating reagent, 2,4,6-tris(tert-butoxy)-1,3,5-triazine (TriAT-tBu) has been developed for the acid-catalyzed tert-butylation of alcohols and carboxylic acids. The reaction of various alcohols and carboxylic acids with TriAT-tBu in the presence of a catalytic amount of an acid provided the corresponding tert-butyl ethers and esters in good to high yields. TriAT-tBu is an air-stable solid synthesized in good yield from inexpensive starting materials, namely, cyanuric chloride, tBuOH, and sodium hydride.
- Yamada, Kohei,Hayakawa, Naoko,Fujita, Hikaru,Kitamura, Masanori,Kunishima, Munetaka
-
-
Read Online
- Convenient preparation of tert-butyl esters
-
A general method is presented for the preparation of tert-butyl esters by the gentle warming of the carboxylic acid in the presence of excess of tert-butyl acetoacetate and a catalytic amount of acid. This method generates only low pressures, and is there
- Taber, Douglass F.,Gerstenhaber, David A.,Zhao, Xia
-
-
Read Online
- Gram-Scale Preparation of Acyl Fluorides and Their Reactions with Hindered Nucleophiles
-
A series of acyl fluorides was synthesized at 100 mmol scale using phase-transfer-catalyzed halogen exchange between acyl chlorides and aqueous bifluoride solution. The convenient procedure consists of vigorous stirring of the biphasic mixture at room temperature, followed by extraction and distillation. Isolated acyl fluorides (usually 7-20 g) display excellent purity and can be transformed into sterically hindered amides and esters when treated with lithium amide bases and alkoxides under mild conditions.
- Tryniszewski, Micha?,Barbasiewicz, Micha?
-
p. 1446 - 1460
(2021/11/30)
-
- Cobalt-Catalyzed Highly Regioselective Three-Component Arylcarboxylation of Acrylate with Aryl Bromides and Carbon Dioxide
-
Cobalt-catalyzed regioselective three-component arylcarboxylation of acrylate with aryl bromides and carbon dioxide has been developed. The reaction is carried out by using cobalt chloride as a precatalyst and zinc powder as a reducing reagent under CO2 (1 atm) at 40 °C. A range of aryl bromides are used for this reaction, leading to a series of valuable carboxylic acids with high regioselectivity and functional-group compatibility. Mechanistic experiments and DFT calculations indicate that this arylcarboxylation reaction involves the reaction of CO2 with a cobalt enolate intermediate to form the C?C bond.
- Hang, Wei,Liang, Nianjie,Liu, Yuzhou,Xi, Chanjuan
-
p. 4941 - 4946
(2021/10/30)
-
- Selective Construction of C?C and C=C Bonds by Manganese Catalyzed Coupling of Alcohols with Phosphorus Ylides
-
Herein, we report the manganese catalyzed coupling of alcohols with phosphorus ylides. The selectivity in the coupling of primary alcohols with phosphorus ylides to form carbon-carbon single (C?C) and carbon-carbon double (C=C) bonds can be controlled by the ligands. In the conversion of more challenging secondary alcohols with phosphorus ylides the selectivity towards the formation of C?C vs. C=C bonds can be controlled by the reaction conditions, namely the amount of base. The scope and limitations of the coupling reactions were thoroughly evaluated by the conversion of 21 alcohols and 15 ylides. Notably, compared to existing methods, which are based on precious metal complexes as catalysts, the present catalytic system is based on earth abundant manganese catalysts. The reaction can also be performed in a sequential one-pot reaction generating the phosphorus ylide in situ followed manganese catalyzed C?C and C=C bond formation. Mechanistic studies suggest that the C?C bond was generated via a borrowing hydrogen pathway and the C=C bond formation followed an acceptorless dehydrogenative coupling pathway. (Figure presented.).
- Liu, Xin,Werner, Thomas
-
p. 1096 - 1104
(2020/12/31)
-
- PEPTIDOMIMETIC N5-METHYL-N2-(NONANOYL-L-LEUCYL)-L-GLUTAMINATE DERIVATIVES, TRIAZASPIRO[4.14]NONADECANE DERIVATIVES AND SIMILAR COMPOUNDS AS INHIBITORS OF NOROVIRUS AND CORONAVIRUS REPLICATION
-
Peptidomimetic N5-methyl-N2-(nonanoyl-L-leucyl)-L-glutaminate derivatives, triazaspiro[4.14]nonadecane derivatives and similar compounds for use in methods of inhibiting the replication of noroviruses and coronaviruses in a biological sample or patient, for use in reducing the amount of noroviruses or coronaviruses in a biological sample or patient, and for use in treating norovirus and coronavirus in a patient, comprising administering to said biological sample or patient a safe and effective amount of a compound represented by formulae I or II, or a pharmaceutically acceptable salt thereof. The present description discloses the synthesis and characterisation of exemplary compounds as well as pharmacological data thereof (e.g. page 99 to page 271; examples 1 to 3; compounds A1 to A104 and Bl to B66; tables A to E).
- -
-
Paragraph 00455; 00540; 00555
(2021/09/26)
-
- Nickel-catalyzed: C-alkylation of thioamide, amides and esters by primary alcohols through a hydrogen autotransfer strategy
-
A simple catalyst of Ni(OAc)2 and P(t-Bu)3 enables selective C-alkylation of thioacetamides and primary acetamides with alcohols for the first time. Monoalkylation of thioamides, amides and t-butyl esters occurs in excellent yields (>95%). Mechanistic studies reveal that the reaction proceeds via a hydrogen autotransfer pathway. This journal is
- Yang, Peng,Wang, Xiuhua,Ma, Yu,Sun, Yaxin,Zhang, Li,Yue, Jieyu,Fu, Kaiyue,Zhou, Jianrong Steve,Tang, Bo
-
supporting information
p. 14083 - 14086
(2020/11/20)
-
- Chelation-Based Homologation by Reaction of Organometallic Reagents with O -Alkyl S -Pyridin-2-yl Thiocarbonates: Synthesis of Esters from Grignard Reagents
-
The one-carbon homologative esterification of Grignard reagents with O- alkyl S -pyridin-2-yl thiocarbonates has been explored. This one-step synthesis of esters from Grignard reagents is the first case to involve chelation-stabilized intermediates.
- Hashimoto, Yoshimitsu,Mano, Koudai,Morita, Nobuyoshi,Suzuki, Tomoyuki,Tamura, Osamu,Tanaka, Kosaku,Usami, Shun
-
supporting information
p. 1561 - 1564
(2019/08/07)
-
- Hydrosilane-Promoted Facile Deprotection of tert-Butyl Groups in Esters, Ethers, Carbonates, and Carbamates
-
Combination of PdCl2 with 1,1,3,3-tetramethyldisiloxane in the presence of activated carbon was found to be an effective catalyst system for the cleavage reaction of C?O bond of O?t-Bu moieties. The present catalytic reaction offers a practical method for the deprotection of tert-butyl esters, tert-butyl ethers, O-Boc, and N-Boc derivatives under mild conditions. The addition of activated carbon in the reaction mixture was proved to be crucial for not only sustaining the catalytic activity but also trapping the palladium species after the reaction. (Figure presented.).
- Ikeda, Takuya,Zhang, Zhenzhong,Motoyama, Yukihiro
-
supporting information
p. 673 - 677
(2019/01/04)
-
- Bidentate Ru(II)-NC Complexes as Catalysts for α-Alkylation of Unactivated Amides and Esters
-
Five Ru(II)-NC complexes were tested as catalysts for α-alkylation of unactivated amides using alcohols as alkylating agents, and complex {(C5H4N)-(C6H4)}RuCl(CO)(PPh3)2 (1) showed the highest activity. With 0.5 mol% catalyst loading, a series of α-alkylated amides were isolated at 80 °C within 6 hours. Furthermore, under similar conditions, complex 1 was also active for α-alkylation of unactivated esters with alcohols, and the reaction time was shortened to 1.5 hours. The catalytic performance of 1 is comparable to the best reported catalyst.
- Gong, Dawei,Hu, Bowen,Yang, Weiwei,Chen, Dafa
-
p. 4841 - 4847
(2019/11/05)
-
- A fast and practical synthesis of tert-butyl esters from 2-tert-butoxypyridine using boron trifluoride·diethyl etherate under mild conditions
-
A practical direct preparation of tert-butyl esters from 2-tert-butoxypyridine has been developed. This system features the use of boron trifluoride·diethyl etherate in toluene solvent to rapidly achieve the reaction at room temperature. Using this reaction protocol, a variety of tert-butyl esters were synthesized from several different carboxylic acids at high yields. This practical procedure provides a promising and effective approach to the protection of carboxylic acids with a tert-butyl group.
- La, Minh Thanh,Kim, Hee-Kwon
-
p. 3748 - 3754
(2018/05/28)
-
- NCP ligand, [...] complex, synthesis method, intermediate and application
-
The invention discloses an NCP ligand, iridium complex, synthetic method, intermediate and application thereof. The invention provides an NCP ligand and an NCP ligand iridium complex, wherein R1, R2, R3, R4, R5, R6 and R7 separately represent hydrogen atom or C1-C30 alkyl, R' and R'' independently represent C1-C30 alkyl. The invention provides the application of the NCP ligand iridium complex to the catalysis of alkane dehydrogenation reaction, olefin isomerization reaction, alcohol dehydrogenation reaction, ester alpha alkylation reaction, and amide alpha alkylation reaction. The NCP ligand provided by the invention contains dialkyl substituted phosphine, which has strong electron donating ability and can form a NCP ligand iridium complex by complexing with iridium. The NCP ligand iridium complex uses pyridine to replace a conventional alkyl phosphate electron donor, and has the advantages of good stability, high selectivity on alkane dehydrogenation reaction, mild reaction conditions, good catalytic effect, and industrial production prospect.
- -
-
Paragraph 0122; 0206-0208
(2018/07/30)
-
- Manganese-Catalyzed α-Alkylation of Ketones, Esters, and Amides Using Alcohols
-
Herein we report the manganese-catalyzed C-C bond-forming reactions via α-alkylation of ketones, amides, and esters, using primary alcohols. β-Alkylation of secondary alcohols by primary alcohols to obtain α-alkylated ketones is also reported. The reactions are catalyzed by a (iPr-PNP)Mn(H)(CO)2 pincer complex under mild conditions in the presence of (catalytic) base liberating water (and H2 in the case of secondary alcohol alkylation) as the sole byproduct.
- Chakraborty, Subrata,Daw, Prosenjit,Ben David, Yehoshoa,Milstein, David
-
p. 10300 - 10305
(2018/10/20)
-
- Sustainable Alkylation of Unactivated Esters and Amides with Alcohols Enabled by Manganese Catalysis
-
The first example of manganese-catalyzed C-alkylation of the carboxylic acid derivatives is reported. The bench-stable homogeneous manganese complex enables the transformation of the renewable alcohol and carboxylic acid derivative feedstock to higher value esters and amides. The reaction operates via hydrogen autotransfer and ideally produces water as the only side product. Importantly, aliphatic-, benzylic-, and heterocyclic-containing alcohols can be used as alkylating reagents, eliminating the need for mutagenic alkyl halides.
- Jang, Yoon Kyung,Krückel, Tobias,Rueping, Magnus,El-Sepelgy, Osama
-
supporting information
p. 7779 - 7783
(2018/12/14)
-
- A strategy for generating aryl radicals from arylborates through organic photoredox catalysis: Photo-Meerwein type arylation of electron-deficient alkenes
-
Photoinduced reactions of arylboronic acids with electron deficient alkenes under mild organic photoredox catalysis conditions lead to the formation of Meerwein arylation type adducts via the generation of aryl radicals.
- Iwata,Tanaka,Kubosaki,Morita,Yoshimi
-
supporting information
p. 1257 - 1260
(2018/02/09)
-
- TRANSESTERIFICATION REACTION BY MEANS OF IRON CATALYST
-
Provided is a catalyst for transesterification reactions, which contains an iron salen complex. Also provided is a method for producing an ester compound, which is characterized by carrying out a transesterification reaction between a starting material ester and a starting material alcohol with use of the catalyst.
- -
-
Paragraph 0134; 0135; 0141-0143
(2017/10/10)
-
- μ-Oxo-Dinuclear-Iron(III)-Catalyzed O-Selective Acylation of Aliphatic and Aromatic Amino Alcohols and Transesterification of Tertiary Alcohols
-
A highly chemoselective and reactive μ-oxo-dinuclear iron(III) salen catalyst for transesterification was developed. The developed iron complex catalyzed acylation of aliphatic amino alcohols with nearly perfect O-selectivity, even when using activated esters, for which chemoselectivity is more difficult to control. In addition, O-selective transesterification of aromatic amino alcohols was achieved for the first time. The high activity of the iron complex enabled the use of sterically congested tertiary alcohols, including unprecedented tert-butanol.
- Horikawa, Rikiya,Fujimoto, Chika,Yazaki, Ryo,Ohshima, Takashi
-
supporting information
p. 12278 - 12281
(2016/08/24)
-
- General and Mild Cobalt-Catalyzed C-Alkylation of Unactivated Amides and Esters with Alcohols
-
The borrowing hydrogen or hydrogen autotransfer methodology is an elegant and sustainable or green concept to construct carbon-carbon bonds. In this concept, alcohols, which can be obtained from barely used and indigestible biomass, such as lignocellulose, are employed as alkylating reagents. An especially challenging alkylation is that of unactivated esters and amides. Only noble metal catalysts based on iridium and ruthenium have been used to accomplish these reactions. Herein, we report on the first base metal-catalyzed α-alkylation of unactivated amides and esters by alcohols. Cobalt complexes stabilized with pincer ligands, recently developed in our laboratory, catalyze these reactions very efficiently. The precatalysts can be synthesized easily from commercially available starting materials on a multigram scale and are self-activating under the basic reaction conditions. This Co catalyst class is also able to mediate alkylation reactions of both esters and amides. In addition, we apply the methodology to synthesize ketones and to convert alcohols into aldehydes elongated by two carbon atoms.
- Deibl, Nicklas,Kempe, Rhett
-
p. 10786 - 10789
(2016/09/09)
-
- A General and mild catalytic α-alkylation of unactivated esters using Alcohols
-
Catalytic α-alkylation of esters with primary alcohols is a desirable process because it uses low-toxicity agents and generates water as the by-product. Reported herein is a NCP pincer/Ir catalyst which is highly efficient for α-alkylation of a broad scope of unactivated esters under mild reaction conditions. For the first time, alcohols alkylate unactivated α-substituted acyclic esters, lactones, and even methyl and ethyl acetates. This method can be applied to the synthesis of carboxylic acid derivatives with diverse structures and functional groups, some of which would be impossible to access by conventional enolate alkylations with alkyl halides. In a pinch: An NCP pincer/iridium catalyst is highly efficient for the α-alkylation of unactivated esters using alcohol under mild reaction conditions. The reaction is simple, clean, and scalable (1-10 mmol), and the scope with respect to the ester is wide.
- Guo, Le,Ma, Xiaochen,Fang, Huaquan,Jia, Xiangqing,Huang, Zheng
-
supporting information
p. 4023 - 4027
(2015/03/30)
-
- Intramolecular rearrangement of α-azidoperoxides: An efficient synthesis of tert-butyl esters
-
An unprecedented intramolecular rearrangement of α-azidoperoxides, promoted by simple organic base to provide tert-butyl esters, has been presented. Further, a one-pot methodology consisting of in situ generation of the α-azidoperoxides from corresponding aldehydes followed by base-promoted rearrangement to obtain the desired ester has also been executed. Relevant mechanistic studies, to provide the proof for intramolecular alkoxy transfer, are investigated.
- Pramanik, Suman,Reddy, Reddy Rajasekhar,Ghorai, Prasanta
-
p. 1393 - 1396
(2015/03/30)
-
- LED lighting as a simple, inexpensive, and sustainable alternative for Wolff rearrangements
-
The Wolff rearrangement is one of the best methods for chain homologation. However, it still suffers from many drawbacks with respect to its practical execution in the laboratory. We wish to demonstrate the use of commercial LED lamps as a sustainable alternative for the classic experimental protocols typically used for Wolff rearrangements. This journal is
- Bernardim, Barbara,Hardman-Baldwin, Andrea M.,Burtoloso, Antonio C. B.
-
p. 13311 - 13314
(2015/02/19)
-
- Palladium-Catalyzed α,β-Dehydrogenation of Esters and Nitriles
-
A highly practical and general palladium-catalyzed methodology for the α,β-dehydrogenation of esters and nitriles is reported. Generation of a zinc enolate or (cyanoalkyl)zinc species followed by the addition of an allyl oxidant and a palladium catalyst results in synthetically useful yields of α,β-unsaturated esters, lactones, and nitriles. Preliminary mechanistic investigations are consistent with reversible β-hydride elimination and turnover-limiting, propene-forming reductive elimination.
- Chen, Yifeng,Romaire, Justin P.,Newhouse, Timothy R.
-
supporting information
p. 5875 - 5878
(2015/05/27)
-
- Ti/Ni-mediated inter- and intramolecular conjugate addition of aryl and alkenyl halides and triflates
-
In this work, we show that the unique combination of a nickel catalyst and Cp2TiCl allows the direct conjugate addition of aryl and alkenyl iodides, bromides, and to a lesser extent, chlorides and triflates to α,β-unsaturated carbonyls at room temperature, without requiring the previous formation of an organometallic nucleophile. The reaction proceeds inter- and intramolecularly with good functional group compatibility, which is key for the development of free protecting group methodologies. Carbo- and heterocycles of five- and six-membered rings are obtained in good yields. Moreover, some insights about the mechanism involved have been obtained from cyclic voltammetry, UV-vis, and HRTEM measurements.
- Marquez, Irene R.,Miguel, Delia,Millan, Alba,Marcos, M. Luisa,De Cienfuegos, Luis Alvarez,Campana, Araceli G.,Cuerva, Juan M.
-
p. 1529 - 1541
(2014/03/21)
-
- Catalyzation of 1,4-additions of arylboronic acids to α,β- unsaturated substrates using nickel(I) complexes
-
Nickel(I) complexes were generated in situ from Ni (PPh3) 2Cl2 using activated iron and the complexes combined with N,N′-bis(4-fluorobenzylidene) ethane-1,2-diamine (BFBED) were then used as a catalyst for the 1,4-addition reaction of arylboronic acids to α,β-unsaturated substrates. The reaction proceeded to completion and did not require the addition of a base but the addition of potassium iodide is crucial to this cross-coupling reaction. Moreover, experimental observations suggested a possible Ni(I)-Ni(III) catalytic cycle mechanism.
- Meng, Jing-Jing,Gao, Min,Dong, Min,Wei, Yu-Ping,Zhang, Wen-Qin
-
p. 2107 - 2109
(2014/04/03)
-
- ZINC CLUSTER
-
Disclosed is a novel zinc cluster compound represented by general formula (1): Zn4O (OCOR)6 (RCOOH)n, wherein R represents an alkyl group which has 1 to 4 carbon atoms and may be substituted with a halogen atom, and n repr
- -
-
Page/Page column 4
(2012/07/14)
-
- Heck reactions catalyzed by Pd(0)-PVP nanoparticles under conventional and microwave heating
-
Pd(0) nanoparticles stabilized by polyvinylpyrrolidone (Pd-PVP) with a diameter of 3-6 nm in ethanol catalyzed Heck coupling of iodobenzene with different alkenes under microwave heating. Products were obtained in good yields (62-99%) and good selectivity to the E-isomers. Microwave heating proved to be superior to conventional heating, providing products in higher yields and selectivities in short times (12 min).
- Martins, Daniela De L.,Alvarez, Heiddy M.,Aguiar, Lúcia C.S.,Antunes, Octavio A.C.
-
experimental part
p. 47 - 53
(2012/04/11)
-
- Rhodium-catalyzed conjugate addition of Sb-aryl-1,5-azastibocines to α,β-unsaturated carbonyl compounds
-
Rhodium-catalyzed conjugate addition of Sb-aryl-1,5-azastibocines to α,β-unsaturated carbonyl compounds is described. The rhodium-catalyzed reaction was carried out in aqueous N-methy-2-pyrrolidinone (NMP) to give 1,4-conjugate adduct exclusively, while t
- Kakusawa, Naoki,Yasuike, Shuji,Kurita, Jyoji
-
experimental part
p. 1269 - 1283
(2010/10/03)
-
- Rhodium catalyzed 1,4-conjugate addition of 1,5-azastibocines with electron deficient olefins
-
The rhodium-catalyzed reaction of Sb-aryl-1,5-azastibocines with α,β-unsaturated ketones and esters is described. Exclusive formation of 1,4-conjugate adduct was achieved in aqueous NMP (N-methyl-2-pyrrolidinone) in the presence of 5 mol% of [RhCl(cod)]s
- Kakusawa, Naoki,Kurita, Jyoji
-
scheme or table
p. 1502 - 1504
(2009/10/24)
-
- Highly efficient and reusable polyaniline-supported palladium catalysts for open-air oxidative heck reactions under base-and ligand-free conditions
-
Oxidative Heck reactions of arylboronic acids and alkenes are carried out in the presence of polyaniline-supported palladium catalysts using air as a co-oxidant to afford the Heck products with excellent yields and selectivities under base-and ligand-free conditions. The catalyst was recovered by simple filtration and used for several cycles with consistent activity.
- Likhar, Pravin R.,Roy, Moumita,Roy, Sarabindu,Subhas,Kantam, M. Lakshmi,Sreedhar
-
experimental part
p. 1968 - 1974
(2009/07/25)
-
- Palladium/phosphite-catalyzed 1,4-addition of arylboronic acids to acrylic acid derivatives
-
(Chemical Equation Presented) 1,4-Addition of arylboronic acids to acrylic acid derivatives proceeds efficiently in the presence of a palladium catalyst system of Pd(OAc)2/(PhO)3P to produce the corresponding 3-arylpropionic acid derivatives. The use of the phosphite ligand is the key to conducting the addition smoothly with suppressing the competing Mizoroki-Heck-type oxidative coupling.
- Horiguchi, Hakaru,Tsurugi, Hayato,Satoh, Tetsuya,Miura, Masahiro
-
p. 1590 - 1592
(2008/09/17)
-
- Indium(III) acetate-catalyzed intermolecular radical addition of organic iodides to electron-deficient alkenes
-
In the presence of phenylsilane and a catalytic amount of indium(III) acetate, organic iodides added to electron-deficient alkenes in ethanol at room temperature. Both simple and functionalized organic iodides were applicable to this reaction. A plausible reaction mechanism involves the formation of indium hydride species by hydride transfer from silicon to indium and an indium hydride-mediated radical chain process.
- Miura, Katsukiyo,Tomita, Mitsuru,Ichikawa, Junji,Hosomi, Akira
-
p. 133 - 136
(2008/09/16)
-
- Palladium(II)-catalyzed conjugate addition of arylsiloxanes in water
-
Equation Presented Palladium-phosphinous acids catalyze the conjugate addition of arylsiloxanes to a wide range of α.β-unsaturated substrates in water microwave-assisted procedure is described that uses 5 mol % of POPd1 to afford /-substituted ketones, aldehydes, esters, nitriles, an nitroalkanes in 83% to 96% yield within 4 h. This method eliminates the need for stoichiometric additives and an excess of arylsiloxane, an does not require an inert atmosphere.
- Lerebours, Rachel,Wolf, Christian
-
p. 2737 - 2740
(2008/02/07)
-
- Silylation of aryl iodides with 1,1,1,3,5,5,5-heptamethyltrisiloxane catalyzed by transition-metal complexes
-
The silylation of various kinds of aryl iodides with 1,1,1,3,5,5,5- heptamethyltrisiloxane was achieved by a suitable transition-metal catalyst, such as Pd(0), Pt(0), and Rh(I). These catalytic systems showed dramatically different substrate scope. Georg Thieme Verlag Stuttgart.
- Murata, Miki,Ota, Kosuke,Yamasaki, Hiroyuki,Watanabe, Shinji,Masuda, Yuzuru
-
p. 1387 - 1390
(2008/02/13)
-
- Palladium(0)-catalyzed silylation of aryl halides with triorganosilanes: Synthesis of aryl(2-furyl)silanes
-
Triorganosilanes, which possess two aryl groups on the silicon atom, undergo palladium-catalyzed silylation of aryl iodides. Aryl(2-furyl)silanes thus obtained are potentially useful starting materials for carbon-carbon bond-forming reactions in the prese
- Murata, Miki,Ohara, Hiroya,Oiwa, Ryo,Watanabe, Shinji,Masuda, Yuzuru
-
p. 1771 - 1774
(2007/10/03)
-
- Borrowing hydrogen: Indirect "Wittig" olefination for the formation of C-C bonds from alcohols
-
The successful development of an indirect three-step domino sequence for the formation of C-C bonds from alcohol substrates is described. An iridium-catalysed dehydrogenation of alcohol 1 affords the intermediate aldehyde 2. The desired C-C bond can then be formed by a facile Wittig olefination, yielding the intermediate alkene 3. In the final step the alkene is hydrogenated to afford the indirect Wittig product, the alkane 4. The key to this process is the concept of borrowing hydrogen; hydrogen removed in the initial dehydrogenation step is simply borrowed by the iridium catalyst. Functioning as a hydrogen reservoir, the catalyst facilitates C-C bond formation before subsequently returning the borrowed hydrogen in the final step. Herein we present full details of our examination into both the substrate and reaction scope and the limitations of the catalytic cycle. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Black, Phillip J.,Edwards, Michael G.,Williams, Jonathan M. J.
-
p. 4367 - 4378
(2007/10/03)
-
- Chiral ligand-controlled asymmetric conjugate amination of enoates with lithium mesitylmethyl(trimethylsilyl)amide
-
Lithium mesitylmethyl(trimethylsilyl)amide behaved as a nice amination agent in a chiral ligand-controlled conjugate addition reaction of tert-butyl cinnamate to give the conjugate amination product with 99% ee in 90% yield. Other acyclic and cyclic enoat
- Sakai, Takeo,Doi, Hirohisa,Tomioka, Kiyoshi
-
p. 8351 - 8359
(2007/10/03)
-
- Direct and transfer hydrogenation of ketones and imines with a ruthenium N-heterocyclic carbene complex
-
The dihydride ruthenium N-heterocyclic carbene complex Ru(IMes)(PPh 3)2CO(H)2 (1) (IMes = 1,3-dimesityl-1,3- dihydro-2H-imidazol-2-ylidene) is an efficient catalyst for both direct hydrogenation and transfer hydrogenation
- Burling, Suzanne,Whittlesey, Michael K.,Williams, Jonathan M. J.
-
p. 591 - 594
(2007/10/03)
-
- Neutrophil inhibitors to reduce inflammatory response
-
The invention provides novel compounds selected from the group consisting of: The compounds of the present invention are useful for the treatment and prevention of a variety of diseases and conditions associated with undesirable or abnormal inflammatory responses, such as ischemia-reperfusion injury. Accordingly, the invention further provides pharmaceutical compositions comprising these compounds. The invention still further provides methods of treatment or prevention for the above disorders using theses compounds or the compositions containing them.
- -
-
Page/Page column 24 - 25
(2010/02/05)
-
- Borrowing hydrogen: A catalytic route to C-C bond formation from alcohols
-
Ruthenium complexes have been shown to perform efficient transfer hydrogenation reactions between alcohols and alkenes; in combination with an in situ Wittig reaction, indirect formation of C-C bonds has been achieved from alcohols.
- Edwards, Michael G.,Jazzar, Rodolphe F. R.,Paine, Belinda M.,Shermer, Duncan J.,Whittlesey, Michael K.,Williams, Jonathan M. J.,Edney, Dean D.
-
-
- Lewis Acids as Highly Efficient Catalysts for the Decarboxylative Esterification of Carboxylic Acids with Dialkyl Dicarbonates
-
Mild Lewis acids such as Mg(ClO4)2 show a new level of catalytic activity for the decarboxylative esterification of carboxylic acids with commercially available dialkyl dicarbonates. In the presence of as little as one mol % Mg(ClO4)2 catalyst, carboxylic acids can thus easily and near quantitatively be protected at room temperature, e.g., as methyl, benzyl, or t-butyl esters. Only volatile by-products are released so that the purification of the products is particularly easy. Many sensitive functionalities are tolerated, including even phenol esters, or free hydroxy and BOC groups.
- Goossen,Doehring
-
p. 943 - 947
(2007/10/03)
-
- A novel synthesis of the macrocyclic spermidine alkaloid (+)-(S)-dihydroperiphylline
-
A novel, short, and highly stereoselective synthesis of the macrocyclic spermidine alkaloid (+)-(S)-dihydroperiphylline (15) is described. The key synthetic steps were the stereoselective addition of the chiral amine 1 to the cinnamate 2 and cyclization o
- Sergeyev, Sergey A.,Hesse, Manfred
-
p. 161 - 167
(2007/10/03)
-
- Rhodium(I)-catalyzed 1,2- and 1,4-addition of aryltriethoxysilanes to carbonyl compounds under aqueous basic conditions
-
Aryltriethoxysilanes add to aldehydes and α,β-unsaturated carbonyl compounds in high yield in the presence of a rhodium(I) catalyst and aqueous sodium hydroxide.
- Murata, Miki,Shimazaki, Ryuta,Ishikura, Masanori,Watanabe, Shinji,Masuda, Yuzuru
-
p. 717 - 719
(2007/10/03)
-
- Improved ester interchange catalysts
-
(equation presented) Mixed alkoxide/aryloxide clusters are long-lived and milder than previously reported ester interchange catalysts. They completely transform difficult substrates in a single synthetic operation with lower catalyst and reagent ester loadings. In addition to superior activities, these mixed clusters are kinetically less basic toward enolizable esters.
- Kissling, Rebecca M.,Gagne, Michel R.
-
p. 4209 - 4212
(2007/10/03)
-
- Transformation of Primary Carboxamides to N-(t-Butoxycarbonyl)amines Using CuBr2-LiOBut
-
The reaction of primary carboxamides with the copper(II) reagent prepared from copper(II) bromide and lithium t-butoxide gave the corresponding N-(t-butoxycarbonyl)amines in good to high yields.
- Yamaguchi, Jun-ichi,Hoshi, Kensuke,Takeda, Takeshi
-
p. 1273 - 1274
(2007/10/02)
-
- ORGANOMETALLIC COMPOUNDS OF ZINC AS SELECTIVE NUCLEOPHILIC REAGENTS IN ORGANIC SYNTHESIS
-
The ability of the Reformatsky reagent BrZnCH2CO2tBu 1 to undergo substitution reactions has been verified with several substituted bromides.
- Orsini, F.,Pelizzoni, F.
-
p. 805 - 816
(2007/10/02)
-
- FACILE METHOD FOR THE ACYLATION OF ALCOHOLS AND AMIDES BY THE USE OF 1,1'-DIMETHYLSTANNOCENE AND ACYL CHLORIDES
-
Acylation of alcohols and amides was effected under mild conditions by the use of 1,1'-dimethylstannocene and acyl chlorides, giving the corresponding esters and imides in good to excellent yields.
- Mukaiyama, Teruaki,Ichikawa, Junji,Asami, Masatoshi
-
p. 293 - 296
(2007/10/02)
-