- SYNTHESIS OF HALICHONDRINS
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The present invention provides methods for the synthesis of ketones involving a Ni/Zr-mediated coupling reaction. The Ni/Zr-mediated ketolization reactions can be used in the synthesis of halichondrins (e.g., halichondrin A, B, C; homohalichondrin A, B, C; norhalichondnn A, B, C), and analogs thereof. Therefore, the present invention also provides synthetic methods useful for the synthesis of halichondrins, and analogs thereof. Also provided herein are compounds (i.e., intermediates) useful in the synthesis of halichondrins, and analogs thereof. In particular, the present invention provides methods and compounds useful in the synthesis of compound of Formula (H3-A)
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Paragraph 00752
(2019/01/21)
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- Enantioselective synthesis of BE ring analogues of methyllycaconitine
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The enantioselective synthesis of decahydroquinolines mimicking the BE rings of methyllycaconitine (MLA) is reported. The analogues were synthesised via a one-pot cyclisation using ethyl α-(bromomethyl)acrylate, (R)-1-phenylethanamine and cyclohexanone to
- Dickson, Emma,Pilkington, Lisa I.,Brimble, Margaret A.,Barker, David
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p. 400 - 414
(2015/12/31)
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- A Scalable Synthesis of (R,R)-2,6-Dimethyldihydro-2H-pyran-4(3H)-one
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A scalable synthesis of (R,R)-2,6-dimethyldihydro-2H-pyran-4(3H)-one is reported. Key to this strategy is the Ti(OiPr)4-catalyzed Kulinkovich cyclopropanation of silyl protected (R)-ethyl 3-hydroxybutanoate, and subsequent oxidative fragmentati
- Young, Ian S.,Haley, Matthew W.,Tam, Annie,Tymonko, Steven A.,Xu, Zhongmin,Hanson, Ronald L.,Goswami, Animesh
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p. 1360 - 1368
(2015/11/02)
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- Anaerobic nitroxide-catalyzed oxidation of alcohols using the NO +/NO· redox pair
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A new method for alcohol oxidation using TEMPO or AZADO in conjunction with BF3·OEt2 or LiBF4 as precatalysts and tert-butyl nitrite as a stoichiometric oxidant has been developed. The system is based on a NO+/NO· pair for nitroxide reoxidation under anaerobic conditions. This allows the simple, high-yielding conversion of various achiral and chiral alcohols to carbonyl compounds without epimerization and no formation of nonvolatile byproducts.
- Holan, Martin,Jahn, Ullrich
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supporting information
p. 58 - 61
(2014/01/23)
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- Kinetic resolution of chiral cyclohex-2-enones by rhodium(I)/binap- catalyzed 1,2- and 1,4-additions
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The feasibility of kinetic resolutions of racemic monosubstituted cyclohex-2-enones by Rh/binap-catalyzed reactions was investigated. 1,2-Addition of AlMe3 to the 5-substituted derivatives furnished allylic alcohols in the matched case, while t
- Kolb, Andreas,Hirner, Sebastian,Harms, Klaus,Zezschwitz, Paultheo Von
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supporting information; experimental part
p. 1978 - 1981
(2012/06/18)
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- Synthesis of syn-4,6-dimethyldodecanal, the male sex pheromone and trail-following pheromone of two species of the termite Zootermopsis
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Recently, we reported that syn-4,6-dimethyldodecanal is the male sex pheromone and the trail-following pheromone of the Termopsidae Zootermopsis nevadensis and Zootermopsis angusticollis. In this article, we describe the syntheses of the mixture of the fo
- Ghostin,Bordereau,Braekman
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scheme or table
p. 560 - 568
(2011/05/12)
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- Stereochemical preference of yeast epoxide hydrolase for the O-axial C3 epimers of 1-oxaspiro[2.5]octanes
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The 1-oxaspiro[2.5]octane moiety is a common motif in many biologically active spiroepoxide compounds. Stereochemistry plays an important role in the action of these spiroepoxides, since the O-axial C3 epimers are predominantly responsible for biological
- Weijers, Carel A. G. M.,Koenst, Paul M.,Franssen, Maurice C. R.,Sudhoelter, Ernst J. R.
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p. 3106 - 3114
(2008/04/01)
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- Total synthesis of (±)-arohynapene B
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The total synthesis of (±)-arohynapene B, an anticoccidial agent isolated from the fermentation broth of a fungal strain, has been achieved. The tetrahydronaphthalene ring was constructed by the Diels-Alder reaction between dimethyl acetylenedicarboxylate
- Sugimura, Hideyuki,Uchida, Yuki
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p. 352 - 353
(2007/10/03)
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- Palladium-catalyzed intramolecular hydroalkylation of alkenyl- β-keto esters, α-aryl ketones, and alkyl ketones in the presence of Me 3SiCl or HCI
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Reaction of 3-butenyl β-keto esters or 3-butenyl α-aryl ketones with a catalytic amount of [PdCl2(CH3CN)2] (2) and a stoichiometric amount of Me3SiCl or Me3SiCl/ CuCl2 in dioxane at 25-70°C formed 2-substituted cyclohexanones in good yield with high regioselectivity. This protocol tolerated a number of ester and aryl groups and tolerated substitution at the allylic, enolic, and cis and trans terminal olefinic positions. In situ NMR experiments indicated that the chlorosilane was not directly involved in palladium-catalyzed hydroalkylation, but rather served as a source of HCl, which presumably catalyzes enolization of the ketone. Identification of HCl as the active promoter of palladium-catalyzed hydroalkylation led to the development of an effective protocol for the hydroalkylation of alkyl 3-butenyl ketones that employed sub-stoichiometric amounts of 2, HCl, and CuCl2 in a sealed tube at 70°C.
- Han, Xiaoqing,Wang, Xiang,Pei, Tao,Widenhoefer, Ross A.
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p. 6333 - 6342
(2007/10/03)
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- Palladium-catalyzed cyclization of alkenyl β-keto esters in the presence of chlorotrimethylsilane
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PdCl2(CH3CN)2 catalyzed the cyclization of alkenyl β-keto esters in the presence of a stoichiometric amount of SiMe3Cl to form 2-carboalkoxycyclohexanones in good yield with excellent regioselectivity.
- Pei, Tao,Widenhoefer, Ross A.
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p. 650 - 651
(2007/10/03)
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- A catalytic route to acyclic chiral building blocks: Applications of the catalytic asymmetric conjugate addition of organozinc reagents to cyclic enones
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Through the Cu-phosphoramidite-catalyzed asymmetric conjugate addition a number of chiral cyclic enones are available with high ee. Here we report the sequential conjugate addition to these enones as a route towards multisubstituted chiral cyclic ketones.
- Jagt, Richard B.C.,Imbos, Rosalinde,Naasz, Robert,Minnaard, Adriaan J.,Feringa, Ben L.
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p. 221 - 229
(2007/10/03)
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- A convenient, efficient method for conjugate reductions using catalytic quantities of Cu(I)
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Exposure of enones and enals to either Bu3SnH or PhSiH3 in the presence of ≤ 5 mol % [(Ph3P)CuH]6 leads to products of 1,4-hydride delivery in good yields.
- Lipshutz, Bruce H.,Keith, John,Papa, Patrick,Vivian, Randall
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p. 4627 - 4630
(2007/10/03)
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- Generation of a reducing reagent from Copper(I) salt and hydrosilane. New practical method for conjugate reduction
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Hydride transfer from a hydrosilane to a copper(I) salt is reported. The silicon group of hydrosilanes was smoothly replaced by copper(I) chloride in DMI to give the corresponding metal hydride complex of copper(I). This transformation was applied to conjugate reduction of α,β-unsaturated compounds with a hydrosilane mediated by copper(I) chloride.
- Ito, Hajime,Ishizuka, Tomoko,Arimoto, Kikuo,Miura, Katsukiyo,Hosomi, Akira
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p. 8887 - 8890
(2007/10/03)
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- Low-temperature 13C magnetic resonance. 9.1 steric effects for methyl chemical shift tensors in methylcyclohexanes
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The solid-state low-temperature 13C NMR spectra of 1-(methyl-13C)-1-methylcyclohexane, cis-1-(methyl-13C)-3,5-dimethylcyclohexane, and trans-1-(methyl-13C)-3,5-dimethylcyclohexane have been measured and the prin
- Soderquist, Arien,Facelli, Julio C.,Horton, Walter J.,Grant, David M.
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p. 8441 - 8446
(2007/10/03)
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- Transfer Hydrogenation of Ketones with (1-) as the Precatalyst
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The cluster 1a has been found to be an efficient precatalyst for the transfer hydrogenations of ketones and α,β-unsaturated ketones.With substrates such as (5S)-carvone , (3R)-methylcyclopentanone and (3R)-methylcyclohexanone, moderate to high diastereoselectivities were observed for reduction of the conjugated olefinic and ketonic functionalities respectively.Aromatisation of carvone to 5-isopropyl-2-methylphenol and disproportionation of cyclohex-2-en-1-one to phenol and cyclohexanone have also been found to be catalysed by 1a.Studies with radical inhibitors and other evidence suggest a radical mechanism for the transfer-hydrogenation and aromatisation reactions.In the transfer hydrogenation of cyclohex-2-en-1-one, the rate of conversion of 1a into other soluble species can be modelled accurately if autocatalysis is assumed.The time-dependent concentration profiles of cyclohex-2-en-1-one, cyclohexanone and cyclohexanol are simulated well if autocatalytic formation of an active intermediate followed by consecutive reactions leading to the formation of products is assumed.Such a model is also consistent with the proposed radical mechanism.
- Bhaduri, Sumit,Sharma, Krishna,Mukesh, Doble
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p. 1191 - 1200
(2007/10/02)
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- Hydride-Mediated Homogeneous Catalysis. Catalytic Reduction of α,β-Unsaturated Ketones Using 6 and H2
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Hydride-mediated reduction of α,β-unsaturated ketones catalytic in the hydride reagent is reported using 6 and molecular hydrogen.The reaction proceeds at room temperature and is highly regioselective, affording either the product of conjugate reduction or complete 1,4- and 1,2-reduction to the saturated alcohol, depending on reaction conditions.In the presence of excess phosphine, the process is homogeneous and chemoselective: isolated double bonds are not hydrogenated, even under forcing conditions.This novel catalytic reduction appears to proceed viathe heterolytic activation of molecular hydrogen by highly reactive copper(I) enolate and alkoxide intermediates.
- Mahoney, Wayne S.,Stryker, Jeffrey M.
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p. 8818 - 8823
(2007/10/02)
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- A CONVENIENT PROCEDURE FOR DISSOLVING METAL REDUCTIONS
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Alicyclic α,β-unsaturated ketones react with lithium in ethylenediamine, followed by Jones oxidation, to give cyclic ketones in good yield.The stereoselectivity at the β position parallels that observed with lithium in liquid ammonia.
- Markgraf, J. Hodge,Staley, Stuart Waugh,Allen, Timothy R.
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p. 1471 - 1478
(2007/10/02)
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- ASYMMETRIZATION OF MESO-CYCLIC KETONES USING HOMOCHIRAL ACETAL TEMPLATES
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Employing the homochiral acetal template, asymmetrization of meso-substituted cyclohexanones is explored.By the use of optically-active 2,4-pentanediol as a chiral protecting group, highly diastereoselective acetal cleavage is achieved when treated with organoaluminum reagent.Dialkylaluminum amides are also effective reagents for this reaction.
- Naruse, Yuji,Yamamoto, Hisashi
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p. 6021 - 6030
(2007/10/02)
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- A TOTAL SYNTHESIS OF POLYETHER ANTIBIOTIC (-)-A23187 (CALCIMYCIN)
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A total synthesis of (-)-A23187 (calcimycin) was accomplished by a convergent approach.The key step of synthesis was the stereospecific cyclization of the β-hydroxy ketone into the spiroketal under basic conditions.
- Negri, David P.,Kishi, Yoshito
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p. 1063 - 1066
(2007/10/02)
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