- Allylation of Aldehydes with Allyltin Compounds in Acidic Aqueous Media-A Catalytic Version
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Allylation reaction of aldehydes with allyltributyltin was achieved using Sn catalysts in acidic aqueous media. Exclusive aldehyde selectivity was observed for competitive reactions of aldehydes and ketones with allyltributyltin in the presence of 5 mol%
- Yanagisawa, Akira,Morodome, Miwa,Nakashima, Hiroshi,Yamamoto, Hisashi
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- Preparation of homoallylic alcohols by reaction of aldehydes with η3-allyl- and η3-crotylmolybdenum complexes
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η3-Allyl and η3-methallyl complexes of molybdenum react with aldehydes to give homoallylic alcohols in preparative yields when water is used as a proton source, but the scope of the reaction is narrowed in the case of the η3-crotylmolybdenum complex by the formation of both transposed and nontransposed products.
- Gable,Shanmugham,White
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- Gold(I)-Catalyzed Intramolecular Dehydrative Amination of Sulfamate Esters Tethered to Allylic Alcohols: A Strategy for the Synthesis of Cyclic Sulfamidates
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An efficient synthesis protocol for cyclic sulfamidates has been developed via catalytic intramolecular cyclizations of sulfamate esters tethered to allylic alcohols. The reactions proceed smoothly at room temperature in the presence of (IPr)AuCl (5 mol%) and AgBF4 (5 mol%). This protocol features good to excellent yields, high selectivity, broad substrate scope, and mild reaction conditions. This method is also applicable to the synthesis of a seven-membered sulfamidate. (Figure presented.).
- Park, Yunjeong,Lee, Ji Sun,Ryu, Jae-Sang
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supporting information
p. 2183 - 2188
(2021/03/15)
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- Remote Arylative Substitution of Alkenes Possessing an Acetoxy Group via β-Acetoxy Elimination
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Palladium-catalyzed remote arylative substitution was achieved for the reaction of arylboronic acids with alkenes possessing a distant acetoxy group to provide arylation products having an alkene moiety at the remote position. The use of β-acetoxy elimination as a key step in the catalytic cycle allowed for regioselective formation of unstabilized alkenes after chain walking. This reaction was applicable to various arylboronic acids as well as alkene substrates.
- Kakiuchi, Fumitoshi,Kochi, Takuya,Kumagai, Takaaki,Muto, Kazuma
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supporting information
p. 24500 - 24504
(2021/10/19)
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- Method for synthesizing 8th-site substituted-3,4,7,8-tetrahydro-2H-oxocin-2-one octatomic ring
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The invention discloses a method for synthesizing 8th-site substituted-3,4,7,8-tetrahydro-2H-oxocin-2-one octatomic ring. The synthesis method includes the following steps: performing Grignard reaction on an aldehyde or ketone to obtain an allyl alcohol compound; and performing condensation reaction with 2-(tert-butylsulfonyl)acetic acid to obtain an allyl (tert-butylsulfonyl)acetate compound; performing olefin cross-metathesis reaction under the action of a second generation Grubbs catalyst to obtain a methoxycarbonyl (tert-butylsulfonyl)acetate compound; performing intramolecular reaction byusing anhydrous N,N-dimethylformamide as a solvent in the presence of a catalyst palladium acetate and a ligand triphenylphosphine, so as to produce a 3-tert-butylsulfonyl 8th-site substituted-3,4,7,8-tetrahydro-2H-oxocin-2-one octatomic ring lactone compound; and finally removing tert-butylsulfonyl in a reaction solution of sodium amalgam and acetic acid by taking ethanol as a solvent, so as toobtain 8th-site substituted-3,4,7,8-tetrahydro-2H-oxocin-2-one octatomic ring lactone compound. The yield of the method is high, and a solution with a very dilute reaction concentration is not neededin the synthesis of various substituted octatomic ring lactones through intramolecular catalysis by palladium, so the process conditions are simple and universal.
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Paragraph 0018-0023; 0026
(2019/10/01)
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- Stereoselective Barbier-Type Allylations and Propargylations Mediated by CpTiCl3
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CpTiCl2, prepared in situ by manganese reduction of CpTiCl3, is an excellent new system for the Barbier-type allylation and propargylation of carbonyl compounds. It can be used in catalytic amounts when combined with Et3N·HBr/TMSBr, which acts as a regenerating system. The high regio- and stereoselectivity shown by this system makes it useful for prenylation and crotylation processes in the synthesis of natural products.
- López-Martínez, Josefa L.,Torres-García, Irene,Rodríguez-García, Ignacio,Mu?oz-Dorado, Manuel,álvarez-Corral, Miriam
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p. 806 - 816
(2019/01/24)
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- Catalytic Nucleophilic Allylation Driven by the Water-Gas Shift Reaction
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The ruthenium-catalyzed allylation of aldehydes with allylic pro-nucleophiles has been demonstrated to be an efficient means to form carbon-carbon bonds under mild conditions. The evolution of this reaction from the initial serendipitous discovery to its general synthetic scope is detailed, highlighting the roles of water, CO, and amine in the generation of a more complete catalytic cycle. The use of unsymmetrical allylic pro-nucleophiles was shown to give preferential product formation through the modulation of reaction conditions. Both (E)-cinnamyl acetate and vinyl oxirane were efficiently used to form the anti-branched products (up to >20:1 anti/syn) and E-linear products (up to >20:1 E/Z) in high selectivity with aromatic, α,β-unsaturated, and aliphatic aldehydes, respectively. Attempts to render the reaction enantioselective are highlighted and include enantioenrichment of up to 75:25 for benzaldehyde.
- Denmark, Scott E.,Matesich, Zachery D.,Nguyen, Son T.,Milicevic Sephton, Selena
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- Syntheses of 4-Acetoxy-or acetylthio-2-substituted tetrahydrothiophene
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The generality of a three-step route for the preparation of 4-Acetoxy-2-Alkyltetrahydrothiophenes was investigated, which started from 1-Alken-4-ols including epoxidation, mesylation and intramolecular nucleophilic substitution. 4-Acetoxy-2-Alkyltetrahydr
- Li, Yaxi,Ding, Rui,Liu, Yongguo,Ma, Bianbian,Sun, Baoguo,Tian, Hongyu
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p. 254 - 272
(2018/02/22)
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- Remarkable Influence of Cobalt Catalysis on Epoxide Ring-Opening with Sulfoxonium Ylides
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Cobalt demonstrates a remarkable ability to catalytically divert the course of epoxide to oxetane ring expansion via reaction with a sulfoxonium ylide. An expanded survey of transition-metal catalysts has confirmed that cobalt salts uniquely instead deliv
- Jamieson, Megan L.,Brant, Nicola Z.,Brimble, Margaret A.,Furkert, Daniel P.
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p. 3952 - 3956
(2017/08/29)
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- Copper-mediated oxysulfonylation of alkenyl oximes with sodium sulfinates: a facile synthesis of isoxazolines featuring a sulfone substituent
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A novel and efficient Cu(OAc)2-mediated oxysulfonylation of alkenyl oximes with sodium sulfonates was developed. The reactions are easy to conduct, occur under mild conditions, and form a broad range of sulfone-substituted isoxazolines in good yields.
- Wang, Li-Jing,Chen, Manman,Qi, Lin,Xu, Zhidong,Li, Wei
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supporting information
p. 2056 - 2059
(2017/02/15)
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- Divergent reactivity via cobalt catalysis: An epoxide olefination
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Cobalt salts exert an unexpected and profound influence on the reactivity of epoxides with dimethylsulfoxonium methylide. In the presence of a cobalt catalyst, conditions for epoxide to an oxetane ring expansion instead deliver homoallylic alcohol products, corresponding to a two-carbon epoxide homologation/ring-opening tandem process. The observed reactivity change appears to be specifically due to cobalt salts and is broadly applicable to a variety of epoxides, retaining the initial stereochemistry. This transformation also provides operationally simple access to enantiopure homoallylic alcohols from chiral epoxides without use of organometallic reagents. Tandem epoxidation-homologation of aldehydes in a single step is also demonstrated.
- Jamieson, Megan L.,Hume, Paul A.,Furkert, Daniel P.,Brimble, Margaret A.
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supporting information
p. 468 - 471
(2016/02/18)
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- Metal-Free Autoxidative Nitrooxylation of Alkenyl Oximes with Molecular Oxygen
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A metal-free aerobic autoxidative nitrooxylation of alkenyl oximes mediated by tert-butyl nitrite is described. Molecular oxygen is used as the oxidizing reagent, avoiding use of organic trapping reagents such as 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMP
- Zhang, Xiao-Wei,Xiao, Zu-Feng,Zhuang, Yan-Jun,Wang, Mei-Mei,Kang, Yan-Biao
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supporting information
p. 1942 - 1945
(2016/07/06)
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- Oxime-mediated oxychlorination and oxybromination of unactivated olefins
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An oxime-mediated oxychlorination and oxybromination of unactivated olefins relying on palladium catalysis has been developed. A wide range of chlorinated and brominated isoxazolines has been synthesized in moderate to good yields. To demonstrate the value of the method, the brominated isoxazoline has been further converted to other useful synthetic feedstock.
- Dong, Kui-Yong,Qin, Hai-Tao,Liu, Feng,Zhu, Chen
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supporting information
p. 1419 - 1422
(2015/03/04)
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- Copper-Catalyzed Oxy-Alkenylation of Homoallylic Alcohols to Generate Functional syn-1,3-Diol Derivatives
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A novel method for the synthesis of a wide range of functionalized 1,3-diol derivatives is reported. Employing a copper-catalyzed oxy-alkenylation strategy, a range of readily available, substituted homoallylic alcohol derivatives and alkenyl(aryl) iodonium salts combine to form syn-1,3-carbonates in excellent yield and with high selectivity. Furthermore, the products formed are amenable to an iterative reaction sequence, thus affording highly complex polyketide-like fragments. Polyols: The reported copper-catalyzed oxy-alkenylation strategy works well for a range of readily available, substituted homoallylic alcohol derivatives and alkenyl(aryl) iodonium salts to form syn-1,3-carbonates in excellent yield and high selectivity. Furthermore, the products formed are amenable to an iterative reaction sequence, thus affording highly complex polyketide-like fragments.
- Holt, Dean,Gaunt, Matthew J.
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supporting information
p. 7857 - 7861
(2015/06/30)
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- CARBOXAMIDE DERIVATIVES
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The present invention provides a compound of formula (I) or a pharmaceutically acceptable salt thereof; a method for manufacturing the compounds of the invention, and its therapeutic uses. The present invention further provides a combination of pharmacologically active agents and a pharmaceutical composition.
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Paragraph 0816-0818
(2015/12/17)
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- Dibutyltin oxide mediated diastereoselective cyclodehydration/sulfonylation of 1,2,4-triols
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Dibutyltin oxide (Bu2SnO) mediated cyclodehydration or sulfonylation of 1,2,4-triols is predictably diastereoselective depending on the steric bulk of the substituents at C4. A larger difference (ΔA-value >1 kcal/mol) leads to the syn-1,2,4-triols favouring cyclodehydration (78-85%) to form 3-hydroxytetrahydrofurans, with the anti-1,2,4-triols favouring monosulfonylation (66-87%). Triols from symmetrical ketones preferentially undergo cyclodehydration in high yield (>75%) due to a gem-disubstituent effect. Thus, the 1,2,4-triols derived from simple cyclic ketones also favour cyclodehydration to form spirocyclic 3-hydroxytetrahydrofurans in 72-79% yields.
- Gamedze, Makhosazana P.,Nkambule, Comfort M.
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supporting information
p. 1825 - 1829
(2015/03/30)
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- Copper-catalyzed oxyazidation of unactivated alkenes: A facile synthesis of isoxazolines featuring an azido substituent
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A novel and efficient Cu(OAc)2-catalyzed oxyazidation of unactivated alkenes was developed. The reactions are easy to conduct, occur under mild conditions, and form azido-substituted isoxazolines in good yields.
- Zhu, Liping,Yu, Hongmei,Xu, Zhaoqing,Jiang, Xianxing,Lin, Li,Wang, Rui
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supporting information
p. 1562 - 1565
(2014/04/17)
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- Copper-catalyzed 5-endo-trig cyclization of ketoxime carboxylates: A facile synthesis of 2-arylpyrroles
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A novel and facile copper-catalyzed 5-endo-trig cyclization of ketoxime carboxylates for the synthesis of 2-arylpyrroles has been developed. The reaction tolerates a range of functional groups and is a practical procedure for rapid synthesis of 2-arylpyrroles in high yields under mild conditions. the Partner Organisations 2014.
- Du, Wei,Zhao, Mi-Na,Ren, Zhi-Hui,Wang, Yao-Yu,Guan, Zheng-Hui
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supporting information
p. 7437 - 7439
(2014/07/07)
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- A practical procedure of low valent tin mediated Barbier allylation of aldehydes in wet solvent
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Use of aluminium as the reducing metal in spontaneous bimetal redox reaction has been elegantly exploited for allylation/crotylation of aldehydes in wet solvent. Here, low valent tin was prepared in situ by reduction of SnCl2·2H2O wi
- Vilanova, Conxín,Sánchez-Péris, María,Roldán, Steven,Dhotare, Bhaskar,Carda, Miguel,Chattopadhyay, Angshuman
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p. 6562 - 6567
(2013/11/19)
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- Radical-mediated diamination of alkenes with phenylhydrazine and azodicarboxylates: Highly diastereoselective synthesis of trans-diamines from cycloalkenes
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Metal-free synthesis: Diamination of alkenes by using phenylhydrazine and azodicarboxylates could be achieved in a one-pot manner under very mild conditions (see scheme; Boc=tert-butoxycarbonyl). This process works with the assistance of acetic acid by me
- Zhu, Ming-Kui,Chen, Yu-Chen,Loh, Teck-Peng
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supporting information
p. 5250 - 5254
(2013/05/23)
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- Mesoporous aluminosilicate-catalyzed allylation of carbonyl compounds and acetals
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A mesoporous aluminosilicate (Al-MCM-41) was found to be an effective heterogeneous catalyst for the reaction of both carbonyl compounds and acetals with allylsilanes to afford the corresponding homoallyl silyl ethers and homoallyl alkyl ethers, respectively. Both the mesoporous structure and the presence of aluminum moiety were indispensable for the high catalytic activity of Al-MCM-41. Moreover, Al-MCM-41 could catalyze the reaction of acetals chemoselectively in the presence of the corresponding carbonyl compounds. The solid acid catalyst Al-MCM-41 could be recovered easily by filtration and could be reused three times without a significant loss of catalytic activity.
- Ito, Suguru,Hayashi, Akira,Komai, Hirotomo,Yamaguchi, Hitoshi,Kubota, Yoshihiro,Asami, Masatoshi
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supporting information; experimental part
p. 2081 - 2089
(2011/04/19)
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- Indium triiodide catalyzed direct hydroallylation of esters
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The InI3-catalyzed hydroallylation of esters by using hydroand allysilanes under mild conditions has been accomplished. Many significant groups such as alkenyl, alkynyl, cyano, and nitro ones survive under these conditions. This reaction system, provided routes to both homoallylic alcohols and ethers, in which either elimination of the alkoxy moiety or of the carbonyl oxygen atom could be freely selected by changing the substituents on the alkoxy moiety and on the hydrosilane. In addition, the hydroallylation of lactones took place without ring cleavage to produce the desired cyclic ethers in high yields.
- Nishimoto, Yoshihiro,Inamoto, Yoshihiro,Saito, Takahiro,Yasuda, Makoto,Baba, Akio
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supporting information; experimental part
p. 3382 - 3386
(2010/08/19)
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- METHOD FOR FORMING ALLYLIC ALCOHOLS
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A method of performing a chemical reaction includes reacting an allyl donor and a substrate in a reaction mixture, and forming a homoallylic alcohol in the reaction mixture. The substrate may be an aldehyde or a hemiacetal. The reaction mixture includes a ruthenium catalyst, carbon monoxide at a level of at least 1 equivalent relative to the substrate, and water at a level of at least 1 equivalent relative to the substrate, and an amine at a level of from 0 to 0.5 equivalent relative to the substrate. The reaction mixture may also include a halide, and the equivalents of the amine may be similar to those of the halide. The reacting includes maintaining the reaction mixture at a temperature of at least 40°C. The method may be catalytic in metal, environmentally benign, amenable to large-scale applications, and applicable to a wide range of substrates.
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Page/Page column 47
(2010/04/06)
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- Catalytic, nucleophilic allylation of aldehydes with allyl acetate
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(Chemical Equation Presented) A new catalytic allylation of aldehydes has been developed that employs allyl acetate as the allylating reagent. Under catalysis by ruthenium trichloride (3 mol %) in the presence of carbon monoxide (30 psi), water (1.5 equiv), and Methylamine (0.1 equiv), a wide range of aromatic, olefinic, and aliphatic aldehydes are efficiently allylated under mild conditions (70 °C, 24-48 h). The stoichiometric byproducts of this reaction are carbon dioxide and acetic acid.
- Denmark, Scott E.,Nguyen, Son T.
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supporting information; experimental part
p. 781 - 784
(2009/08/12)
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- Synthesis of highly functionalized δ-lactone-fused cyclopentanoids
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A short and efficient route to δ-lactone-fused cyclopentanoids starting from the easily accessible Diels-Alder adducts between homoallylic alcohol acetates and 1,2,3,4-tetrachloro-5,5-dimethoxycyclopenta-1,3-diene is reported. Since homoallyl alcohols wer
- Khan, Faiz Ahmed,Krishnakumar,Sudheer
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p. 1054 - 1060
(2008/02/02)
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- Novel and efficient method for the allylation of carbonyl compounds and imines using triallylaluminum
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This is the first report of the use of triallylaluminum as a reagent for the allylation of carbonyl compounds and imines. The allylation of ketimines without additional metal catalyst is known so far only in the case of the Grignard reagent. Triallylaluminum is a useful alternative to provide the homoallylic amines in excellent yield upon addition to aldimines and ketimines. The significant reactivity of this reagent was confirmed by its reaction with a sterically rigid ketone such as adamantanone to provide 1-adamantyl-3-buten-1-ol in 98% yield. The chemoselectivity of triallyl-aluminum was demonstrated by using different ketoesters. It is noteworthy that triallylaluminum is prepared from allyl bromide and aluminum metal, and not from a Grignard reagent, and that the procedure is operationally simple, leading to good to excellent product yields.
- Shen, Kao-Hsien,Yao, Ching-Fa
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p. 3980 - 3983
(2007/10/03)
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- HIV protease inhibiting compounds
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A compound of the formula is disclosed as an HIV protease inhibitor. Methods and compositions for inhibiting an HIV infection are also disclosed.
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Page/Page column 150
(2010/02/12)
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- Monomeric metal aqua complexes in the interlayer space of montmorillonites as strong Lewis acid catalysts for heterogeneous carbon-carbon bond-forming reactions
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Montmorillonite-enwrapped copper and scandium catalysts (Cu2-- and Sc3+-monts) were easily prepared by treating Na--mont with the aqueous solution of the copper nitrate and scandium triflate, respectively. The resulting Cu2+- and Sc3+-monts showed outstanding catalytic activities for a variety of carbon-carbon bond-forming reactions, such as the Michael reaction, the Sakurai-Hosomi allylation, and the Diels-Alder reaction, under solvent-free or aqueous conditions. The remarkable activity of the mont catalysts is attributable to the negatively charged silicate layers that are capable of stabilizing metal cations. Furthermore, these catalysts were reusable without any appreciable loss in activity and selectivity. The Cu2+-mont-catalyzed Michael reaction proceeds via a ternary complex in which both the 1,3-dicarbonyl compound and the enone are coordinated to a Lewis acid Cu2+ center.
- Kawabata, Tomonori,Kato, Masaki,Mizugaki, Tomoo,Ebitani, Kohki,Kaneda, Kiyotomi
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p. 288 - 297
(2007/10/03)
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- Indium-catalyzed Barbier allylation reaction
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Barbier allylation reaction of carbonyl compounds with allyl bromide was investigated using a catalytic amount of indium (0), indium (I) or indium (III) salts in the presence of a reducer and chlorotrimethylsilane (TMSCl). The Mn/TMSCl couple turned out to be the most efficient system to regenerate active indium in the allylation reaction of various carbonyl compounds including α- and β-oxygenated aldehydes.
- Augé, Jacques,Lubin-Germain, Nadège,Marque, Sylvain,Seghrouchni, Latifa
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- Organic synthesis in solid media. Silica gel as an effective and reusable medium for the selective allylation of aldehydes with tetraallyltin
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Wet silica gel promotes the chemoselective and almost complete allylation of aldehydes with 0.25-0.30 molar equivalents of tetraallyltin without an organic solvent, leaving no organotin compounds, requiring neither extraction nor chromatographic separatio
- Jin, Yong Zhi,Yasuda, Noriyuki,Furuno, Hiroshi,Inanaga, Junji
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p. 8765 - 8768
(2007/10/03)
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- A Mild Protocol for Allylation and Highly Diastereoselective Syn or Anti Crotylation of Aldehydes in Biphasic and Aqueous Media Utilizing Potassium Allyl- and Crotyltrifluoroborates
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(Equation Presented) Potassium allyl- and crotyltrifluoroborates undergo addition to aldehydes in biphasic media as well as water to provide the corresponding homoallylic alcohols in high yields (≥94%), excellent diastereoselectivity (dr ≥ 98:2), and with
- Thadani, Avinash N.,Batey, Robert A.
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p. 3827 - 3830
(2007/10/03)
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- Iron(III) chloride-catalyzed effective allylation reactions of aldehydes with allyltrimethylsilane
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Iron(III) chloride-catalyzed allylation reactions of a variety of aldehydes with allyltrimethylsilane proceeded efficiently and smoothly to afford the corresponding homoallyl alcohols in high to excellent yields. This novel method could be suitable especi
- Watahiki, Tsutomu,Oriyama, Takeshi
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p. 8959 - 8962
(2007/10/03)
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- Indium(III) chloride/chlorotrimethylsilane as a highly active Lewis acid catalyst system for the Sakurai-Hosomi reaction
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The indium(III) chloride/chlorotrimethylsilane system acts as a catalyst for the Sakurai-Hosomi reaction between allylsilanes and aldehydes. When γ-substituted allylsilanes such as crotylsilane and prenylsilane are used a high regioselectivity for γ-addit
- Onishi, Yoshiyuki,Ito, Takeshi,Yasuda, Makoto,Baba, Akio
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p. 1578 - 1581
(2007/10/03)
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- ROMPgel supported allylboronate: A purification-free method for the preparation of homoallylic alcohols
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Allylboration of various aldehydes was carried out by a ROMPgel supported allylboronate. Filtration and evaporation gave the corresponding homoallylic alcohols in high yield and purity (>95%).
- Arnauld, Thomas,Barrett, Anthony G.M,Seifried, Robert
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p. 7899 - 7901
(2007/10/03)
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- Allyl- and propargylchromium reagents generated by a chromium(III) ate-type reagent as a reductant and their reactions with electrophiles
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A chromium ate-type reagent 'Bu5CrLi2' reacts with allylic and propargylic phosphates to generate the corresponding allyl- and propargylchromium (propargyl = prop-2-ynyl) reagents which further react with a variety of electrophiles such as aldehydes, ketones, imines, and isocyanates to afford the corresponding adducts in high yields.
- Hojo,Sakuragi,Okabe,Hosomi
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p. 357 - 358
(2007/10/03)
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- Aluminum bis(trifluoromethylsulfonyl)amides: New highly efficient and remarkably versatile catalysts for C-C bond formation reactions
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Superacid-derived aluminum catalysts R2AlNTf2 (2-5 mol%) are highly efficient and versatile and are suitable promoters for the allylation and pentadienylation of aldehydes, aldol reactions, aldol cross-coupling of ketones, and Michae
- Marx, Andreas,Yamamoto, Hisashi
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p. 178 - 181
(2007/10/03)
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- Indium-catalyzed allylation of carbonyl compounds with the Mn/TMSCl system
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Allylation of aldehydes and ketones with allyl bromide was performed with a catalytic amount of indium powder (from 0.01 to 0.1 equiv.) in THF in the presence of manganese and trimethylsilyl chloride as the reducing and oxophilic agent, respectively.
- Auge, Jacques,Lubin-Germain, Nadege,Thiaw-Woaye, Aurelie
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p. 9245 - 9247
(2007/10/03)
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- Allylation reactions of acylsilanes as synthetic equivalents of aldehydes. Application of a stereocontrolled synthesis of (1S,2S,5S)-(10S)- and-(10R)-allyl myrtanol
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The allylation of acylsilanes with tetraallyltin in the presence of catalytic amounts of Sc(OTf)3 proceeded smoothly to afford the silylated homoallylic alcohols in good yields. Subsequent protiodesilylation gave the formal adducts of the corre
- Bonini, Bianca Flavia,Comes-Franchini, Mauro,Fochi, Mariafrancesca,Mazzanti, Germana,Nanni, Cristiano,Ricci, Alfredo
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p. 6737 - 6740
(2007/10/03)
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- Sc(OTf)3, an efficient catalyst for addition of allyltrimethysilane to aldehydes: Chemoselective addition to aldehydes in presence of ketone and in situ acylation (3-component coupling)
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Scandium triflate (2-10 mol%) have been found to be a highly efficient catalyst for the addition of allyltrimethylsilane to both activated aromatic and aliphatic aldehydes. However, deactivated (electron rich) aromatic aldehydes gave double allylated products instead. Using a stoichiometric amount of Ac2O in the allylation reaction led directly to homoallylic acetates [in situ acylation catalysed by Sc(OTf)3] and for the first time gave high yields of adducts with moderately electron rich aromatic aldehydes.
- Aggarwal, Varinder K.,Vennall, Graham P.
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p. 1822 - 1826
(2007/10/03)
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- Palladium(II)-Catalyzed Intramolecular Aminocarbonylation of endo-Carbamates under Wacker-Type Conditions
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Pd(II)-catalyzed intramolecular aminocarbonylation of olefins bearing many types of nitrogen nucleophiles has been examined under two typical conditions: acidic conditions [conditions A, typically PdCl2 (0.1 equiv) and CuCl2 (3.0 equiv) under 1 atm of CO at room temperature in methanol] and buffered conditions [conditions B, typically PdCl2 (0.1 equiv) and CuCl2 (2.3 equiv) under 1 atm of CO at 30°C in trimethyl orthoacetate]. Among nitrogen nucleophiles, endocarbamates 7 display distinctive reactivity: endo-carbamates 7a-k smoothly undergo intramolecular aminocarbonylation under conditions B to furnish 4-[(methoxycarbonyl)methyl]-2-oxazolidinones 8a-k in good yields, while they would not undergo the expected reaction under conditions A. Other nitrogen nucleophiles (exo-ureas 1, endo-ureas 3, exo-carbamates 5, and exo-tosylamides 9), on the other hand, satisfactorily undergo aminocarbonylation only under conditions A to give rise to 2,4,6, and 10, respectively, in good yields. Under conditions B, they are unreactive and provide either the expected products in poor yields or intractable mixtures of products. On the basis of this contrasting reactivity between endo-carbamates and other nitrogen nucleophiles, the chemoselective aminocarbonylation of 71-o has been achieved; aminocarbonylation takes place at the endo-carbamate moieties to furnish 81-o exclusively under conditions B, and aminocarbonylation occurs at the exo-carbamate, exo-urea, and exo-tosylamide moieties to yield 13a-d exclusively under conditions A.
- Harayama, Hiroto,Abe, Atsuhiro,Sakado, Tomonori,Kimura, Masanari,Fugami, Keigo,Tanaka, Shuji,Tamaru, Yoshinao
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p. 2113 - 2122
(2007/10/03)
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- Indium Triiodide (InI3)-Catalyzed Allylation of Carbonyl Compounds by Allylic Tins
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Indium triiodide is an effective catalyst for the allylation of aldehydes via the transmetallation with allylic tin compounds. Moreover, the chelation-controlled allylation of α-alkoxyketones proceeded with a catalytic amount of indium triiodide.
- Miyai, Takashi,Inoue, Katsuyuki,Yasuda, Makoto,Baba, Akio
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p. 699 - 700
(2007/10/03)
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- A gem-allyl dianion synthon in water
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The reaction of 1,3-dibromopropene with carbonyl compounds mediated by indium in water gave bis-allylation products connected to the same carbon. Such a reactivity effectively constitutes a gem-allyl dianion synthon.
- Chen, Dong-Li,Li, Chao-Jun
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p. 295 - 298
(2007/10/02)
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- A convenient synthesis of protected and free homoallylic alcohols: Catalytic use of dibutyltin dichloride in the allylation of aldehydes with allyltributyltin
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A new procedure for the allylation of aldehydes with allyltributyltin in the presence of 10 mol% dibutyltin dichloride and either an acid chloride or trimethylsilyl chloride has been developed. Homoallylic esters, carbonates, trimethylsilyl ethers, and alcohols were obtained in up to 99% yield.
- Whitesell, James K.,Apodaca, Richard
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p. 3955 - 3958
(2007/10/03)
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- Allylic tin(IV)-tin(II) chloride-acetonitrile as a novel system for allylation of carbonyls or imines
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Effective allylation of aldehydes, ketones and imines was accomplished by allylic tributyltins 1 in the presence of SnCl2 in an acetonitrile solution. In this reaction system, Sn(IV)-Sn(II) transmetallation must play a key role, generating the
- Yasuda, Makoto,Sugawa, Yoshihiro,Yamamoto, Akihiro,Shibata, Ikuya,Baba, Akio
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p. 5951 - 5954
(2007/10/03)
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- Scandium trifluoromethanesulfonate, a novel catalyst for the addition of allyltrimethylsilane to aldehydes
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Scandium triflate (2-10 mol%) has been found to be a highly efficient catalyst for the addition of allyltrimethylsilane to both aromatic and aliphatic aldehydes.
- Aggarwal, Varinder K.,Vennall, Graham P.
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p. 3745 - 3746
(2007/10/03)
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- Bis(fluorosulfuryl)imide: A Broensted acid catalyst for the addition of allyltrimethylsilane to carbonyl compounds
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The Broensted acid HN(SO2F)2 catalyses the addition of allyltrimethylsilane to carbonyl compounds to give the corresponding homoallylic alcohols in high yields.
- Kaur, Gurmeet,Manju, Kavita,Trehan, Sanjay
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p. 581 - 582
(2007/10/03)
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- Super-acid Catalysed Addition of Allylsilanes to Carbonyl Compounds; Synthetic and Mechanistic Aspects
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The addition of allyltrimethylsilane 8 to a variety of aldehydes and one ketone (cyclohexanone) was found to be induced by the super-acid TfOH2(1+)B(OTf)4(1-) (Tf = CF3SO2).In contrast to the analogous Lewis acid catalysed reaction, only catalytic amounts
- Davis, Anthony P.,Jaspars, Marcel
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p. 2111 - 2118
(2007/10/02)
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- Retro -Brook Rearrangements of Nonconjugated Secondary α-Lithio Ethers: Proof of Stereospecifity and of Retention of Configuration at the Carbanion Center
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The syntheses of two pairs of diastereomeric γ-(trialkylsilyloxy) α-(tributylstannyl) ethers (syn- and anti-6b, syn- and anti-9) are described.Treatment of each of these compounds with n-BuLi in THF at -78 deg C furnished α-lithiated ethers which underwent retro -Brook rearrangements at that temperature within 15-30 min.After aqueous workup, the α-silyl ethers syn-14, anti-14, syn-11, and anti-11, respectively, were isolated isomerically pure in 78-93percent yield.Comparison of the stereochemistry of starting materials and products shows that these rearrangements proceeded stereospecifically and with retention of configuration at the carbanion center.In a cross-over experiment under similar conditions, a 1:1 mixture of the (tributylstannyl) ethers syn-9 and syn-6b gave, via the intermediacy of a 1:1 mixture of the α-lithiated ethers syn-13 and syn-10, the α-silyl ethers syn-11 and syn-14 exclusively.They represent the outcome of intramolecular rearrangements rather than intermolecular processes. Key Words: Stannane, α-alkoxy- / -Brook rearrangement / Configurational stability / α-Lithio ethers
- Hoffmann, Rolf,Brueckner, Reinhard
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p. 2731 - 2740
(2007/10/02)
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- Superacid Catalysis of the Addition of Allysilanes to Carbonyl Compounds
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The superacid TfOH2+B(OTf)4- (Tf = CF3SO2) was found to catalyse the addition of trialkylallysilanes to aldehydes and a ketone (the Sakurai reaction) at levels of ca. 0.5 molpercent; the reactions were clean, highly-yielding, and reg
- Davis, Anthony P.,Jaspars, Marcel
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p. 1176 - 1178
(2007/10/02)
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