- Synthesis of (-)- and (+)-Gummiferol via Asymmetric Synthesis of Glycidic Amides
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An efficient synthesis of the natural product (-)-gummiferol is achieved according to a novel asymmetric methodology of epoxide formation based on a new class of chiral sulfonium salts. This new methodology allows the rapid and efficient construction of t
- García-Ruiz, Cristina,Cheng-Sánchez, Iván,Sarabia, Francisco
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- Total synthesis of (+)-pilosinine via a stereodivergent conjugate addition strategy
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In recent work, asymmetric conjugate addition reactions to chiral 4-phenyl-N-enoyl-1,3-oxazolidinones have been shown to give different stereochemical outcomes depending on the conditions employed. Through the application of stereodivergent reaction conditions, the total synthesis of (+)-pilosinine and the formal synthesis of (?)-pilosinine has been completed from a single enantiomer of the 1,3-oxazolidinone auxiliary.
- Schrank, Cassandra L.,Danneman, Michael W.,Prebihalo, Emily A.,Anderson, Robert E.,Gibson, Tyler J.,Wuest, William M.,Mullins, Richard J.
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- Enantioselective Intermolecular Pd-Catalyzed Hydroalkylation of Acyclic 1,3-Dienes with Activated Pronucleophiles
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We report a highly enantioselective Pd-PHOX-catalyzed intermolecular hydroalkylation of acyclic 1,3-dienes. Meldrum's acid derivatives and other activated C-pronucleophiles, such as β-diketones and malononitriles, react with a variety of aryl- and alkyl-substituted dienes in ≤20 h at room temperature. The coupled products, obtained in up to 96% yield and 97.5:2.5 er, are easily transformed into useful chemical building blocks for downstream synthesis.
- Adamson, Nathan J.,Wilbur, Katherine C. E.,Malcolmson, Steven J.
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p. 2761 - 2764
(2018/03/06)
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- Stereoselective synthesis of the C3-C15 fragment of callyspongiolide
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The synthesis of C3-C15 fragment of callyspongiolide, a 14-membered macrolides isolated from the marine sponge Callyspongia sp., which was collected from the Indonesia, is reported. Highlights of the synthesis include construction of E-olefin through Juli
- Reddy Ramidi, Gopal,Yadav, Jhillu S.,Mohapatra, Debendra K.
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p. 3579 - 3582
(2018/09/10)
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- B(C6F5)3: A New Class of Strong and Bulky Lewis Acid for Exo-Selective Intermolecular Diels-Alder Reactions of Unreactive Acyclic Dienes with α,β-Enals
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Lewis acid B(C6F5)3 catalyzed the Diels-Alder reactions of multisubstituted open-chain dienes and α,β-enals to afford the desired products with high exo-selectivities are reported. The substituent effect of the dienes and dienophiles on the products stereoselectivity was thoroughly investigated, and it was found that most of the desired exo-Diels-Alder products could be obtained in good yields and with high exo-stereoselectivities.
- Zhou, Jia-Hui,Jiang, Bing,Meng, Fei-Fan,Xu, Yun-He,Loh, Teck-Peng
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p. 4432 - 4435
(2015/09/28)
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- NOVEL PYRIMIDINE DERIVATIVE FOR INHIBITING THE GROWTH OF CANCER CELLS
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The present invention provides a novel pyrimidine derivative or pharmaceutically acceptable salt thereof, and a pharmaceutical composition comprising same, which can effectively inhibit the growth of cancer cells induced by the overexpression of EGFR incl
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Page/Page column 53-54
(2011/09/15)
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- De novo synthesis of pentoses via cyanohydrins as key intermediates
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A de novo synthesis of pentoses is described starting from (Z)-2-buten-1,4-diol (1). The key step is the enzyme catalysed enantioselective HCN-addition to O-protected 4-hydroxybut-2-enal using the hydroxynitrile lyase from Hevea brasiliensis, followed by an asymmetric dihydroxylation. For the cyanohydrin reaction the influence of the configuration of the double bond and of the protecting group was investigated. The dihydroxylation step was found to be influenced by the protecting group on position 4.
- Avi, Manuela,Gaisberger, Richard,Feichtenhofer, Sabine,Griengl, Herfried
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scheme or table
p. 5418 - 5426
(2009/10/24)
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- An atom-economic and selective ruthenium-catalyzed redox isomerization of propargylic alcohols. An efficient strategy for the synthesis of leukotrienes
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Catalytic ruthenium complexes in conjunction with an indium cocatalyst and Broensted acid isomerize primary and secondary propargylic alcohols in good yields to provide trans enals and enones exclusively. Readily available indenylbis(triphenylphosphine)ruthenium chloride, in the presence of indium triflate and camphorsulfonic acid, gives the best turnover numbers and reactivity with the broadest range of substrates. Deuterium labeling experiments suggest that the process occurs through propargylic hydride migration followed by protic cleavage of the resultant vinylruthenium intermediate. Application of this method to the synthesis of leukotriene B4 demonstrates its utility and extraordinary selectivity.
- Trost, Barry M.,Livingston, Robert C.
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supporting information; experimental part
p. 11970 - 11978
(2009/02/05)
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- A Cycloaddition Cascade Approach to the Total Synthesis of (-)-FR182877
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An asymmetric synthesis of the cytotoxic natural product, (-)-FR182877 (1), has been achieved. Chirality for the entire structure was established using two (4R)-4-benzyl-2-oxazolidinone-mediated boron aldol reactions. A 19-membered macrocarbocycle was syn
- Evans, David A.,Starr, Jeremy T.
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p. 13531 - 13540
(2007/10/03)
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- A versatile asymmetric synthesis of highly enantiomerically enriched 12(S)-HETE via a combination of enzymatic and chemical processes
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This paper describes a versatile asymmetric synthesis of highly enantiomerically enriched 12(S)-HETE via enzymatic kinetic resolution of the key allylic alcohol synthon and the facile introduction of three alkyne units which were concomitantly converted t
- Suh, Young-Ger,Min, Kyung-Hoon,Lee, Yong-Sil,Seo, Seung-Yong,Kim, Seok-Ho,Park, Hyun-Ju
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p. 3825 - 3828
(2007/10/03)
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- gem-diacetates as carbonyl surrogates for asymmetric synthesis. Total syntheses of sphingofungins E and F
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The equivalent of an asymmetric addition to a carbonyl group with a stabilized anion is accomplished by discriminating between the enantiotopic C-O single bonds of a gem-diacetate. In this way, enantioselective total syntheses of two antifugal agents, sph
- Trost,Lee
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p. 12191 - 12201
(2007/10/03)
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- New 3'-azido-3'-deoxythymidin-5'-yl O-(4-hydroxyalkyl or -alkenyl or -alkylepoxide) carbonate prodrugs: synthesis and anti-HIV evaluation.
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New 5'-O-carbonate prodrugs of zidovudine (AZT) have been synthesized in order to enhance its uptake by HIV-1 infected cells, to improve its anti-HIV potency, and to optimize the intramolecular cyclic rearrangement process related to the 5'-O-(4-hydroxybu
- Vlieghe,Clerc,Pannecouque,Witvrouw,De Clercq,Salles,Kraus
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p. 3014 - 3021
(2007/10/03)
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- Stereochemical aspects of intramolecular palladium catalysed [3+2] cycloadditions of methylenecyclopropanes
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The preparation and intramolecular palladium catalysed [3+2] cycloaddition reactions of a range of substrates containing either stereochemically defined 2,3-disubstituted methylenecyclopropanes 3 or acrylate acceptors 12-15 are described. Evidence is presented which supports the hypothesis that these cycloaddition reactions proceed via palladium-trimethylenemethane type intermediates and that the two carbon-carbon bonds are formed in a highly asynchronous manner.
- Corlay, Herve,Motherwell, William B.,Pennell, Andrew M. K.,Shipman, Michael,Slawin, Alexandra M. Z.,Williams, David J.,Binger, Paul,Stepp, Michael
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p. 4883 - 4902
(2007/10/03)
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- Transannular Diels-Alder cyclization of substituted 13-membered trienes. An approach to the B.C.D.[6.6.5] rings of the 14β-hydroxysteroids
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The transannular Diels-Alder strategy has been applied to three 13-membered macrocyclic trienes whose characteristics are: a cis-trans diene and a cis methoxymethyl enol ether as the dienophile. The successful trials led to three 6.6.5 tricyles having a t
- Langlois, Pascal
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p. 129 - 143
(2007/10/03)
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- A stereospecific transannular Diels-Alder approach to the [6.6.7] tricyclic skeleton related to aphidicolin and scopadulan natural products
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Model trans-cis-cis (TCC) macrocyclic triene 7 was synthesized using a convergent approach. Upon heating at 200°C, a 1,5-hydrogen-shift on the diene moiety was found to compete with the transannular Diels-Alder (TADA) reaction, thus leading to a mixture of tricyclic products. However, the diene rearrangement could be avoided by using boron trifluoride-diethyl ether complex as catalyst at reduced temperature (60°C). The exclusive formation of the trans-syn-cis [6.6.7] (TSC) tricyclic product 8 through an endo approach was observed. This result demonstrates the feasibility of a TADA strategy for synthesizing the title compounds and analogs.
- Hall,Caille,Drouin,Lamothe,Muller,Deslongchamps
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p. 1081 - 1088
(2007/10/02)
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- Total Synthesis of the Polyene Macrolide Antibiotic Roxaticin. II. Total Synthesis of the Roxaticin
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Roxaticin has been synthesized in a convergent manner from the polyol segment 2, which was prepared by the Julia coupling reaction of sulfone 4 and aldehyde 8, and the polyene phosphonate 3.The cyclization was achieved by macrolactonization.
- Mori, Yuji,Asai, Motoya,Kawade, Jun-ichiro,Furukawa, Hiroshi
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p. 5315 - 5330
(2007/10/02)
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- Synthesis of &β-1-Homonojirimycin and &β-1-Homomannojirimycin using the Enzyme Aldolase
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The four stereoisomers of the four-carbon azido sugar 11 have been stereoselectively synthesised by a route involving Sharpless epoxidation and all are found to be substrates for rabbit muscle fructose 1,6-bisphosphate aldolase, giving (after treatment wi
- Holt, Karen E.,Leeper, Finian J.,Handa, Sheetal
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p. 231 - 234
(2007/10/02)
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- Synthesis and transannular Diels-Alder reaction of a 13-membered macrocyclic triene. A synthetic approach towards the tricyclic part A.B.C.[6.6.5] of the veratrum alkaloids
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The syntheses of the acyclic triene cis-trans-trans (3Z,9Z,11E)-13-chloro-3-methoxy-1,1,7,7-tetrakis(methoxycarbonyl)-4- methyltrideca-3,9,11-triene (25), and the corresponding trans-cis-trans (3Z,9E,11E) isomer 37, and trans-trans-trans (3Z,9E,11E) isomer, 46, are described. Compounds 25 and 37 furnished in good yield 13-membered macrocyclic compounds (3Z,9Z,11E)- and (3Z,9E,11Z)-3-methoxy-1,1,7,7-tetrakis(methoxycarbonyl)-4- methylcyclotride-ca-3,9,11-triene (26) and (38) which led to tricyclic compound (cis-anti-cis)-2-methoxy-4,4,11,11-tetrakis(methoxycarbonyl)-1- methyl-tricyclo[7.4.0.02,6]tridec-7-ene (27) by transannular Diels-Alder reaction. Macrocyclization of trans-trans-trans chloride 46 was not successful.
- Quimpere,Ruest,Deslongchamps
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p. 132 - 140
(2007/10/02)
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- A Stereochemically General Synthesis of 2-Deoxyhexoses via the Asymmetric Allylboration of 2,3-Epoxy Aldehydes
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A stereochemically general strategy for the synthesis of 2-deoxyhexoses is described.This new approach involves the asymmetric allylboration of epoxy aldehydes 12 and 13, prepared via the Sharpless asymmetric epoxidation reaction, as a means of establishi
- Roush, William R.,Straub, Julie A.,VanNieuwenhze, Michael S.
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p. 1636 - 1648
(2007/10/02)
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