- Ligand-controlled cobalt-catalyzed remote hydroboration and alkene isomerization of allylic siloxanes
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The Co-catalyzed remote hydroboration and alkene isomerization of allylic siloxanes were realized by a ligand-controlled strategy. The remote hydroboration with dcype provided borylethers, while xantphos favored the formation of silyl enol ethers.
- Huang, Jiaxin,Li, Jie,Yang, Wen,Zhang, Kezhuo,Zhao, Pei,Zhao, Wanxiang
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supporting information
p. 302 - 305
(2022/01/03)
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- Lithium triethylborohydride as catalyst for solvent-free hydroboration of aldehydes and ketones
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Commercially available and inexpensive lithium triethylborohydride (LiHBEt3) acts as efficient catalyst for the solvent-free hydroboration of a wide range of aldehydes and ketones, which were subsequently transformed to corresponding 1° and 2° alcohols in one-pot procedure at room temperature (rt).
- Kuciński, Krzysztof,Hreczycho, Grzegorz
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p. 1912 - 1915
(2019/04/27)
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- Asymmetric Cα-Alkylation of Proline via Chirality Transfers of Conformationally Restricted Proline Derivative: Application to the Total Synthesis of (-)-Amathaspiramide F
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An efficient strategy for the asymmetric synthesis of Cα-tetrasubstituted proline derivatives from proline has been established. A nitrogen-fused bicyclic system was devised to control the stereodynamics of proline. Through N-quaternizations with allylic electrophiles followed by [2,3]-rearrangements, the bicyclic proline system delivered enantioenriched Cα-tetrasubstituted prolines. This strategy was applied to the concise total synthesis of (-)-amathaspiramide F.
- Cho, Hyunkyung,Shin, Jae Eui,Lee, Seokwoo,Jeon, Hongjun,Park, Soojun,Kim, Sanghee
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supporting information
p. 6121 - 6125
(2018/10/02)
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- Rhodium-Catalyzed Synthesis of α,β-Unsaturated Ketones through Sequential C-C Coupling and Redox Isomerization
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A novel Rh(I)-catalyzed sequential C-C coupling and redox isomerization between allylic alcohols and 1,3-dienes has been accomplished. This versatile protocol provides expeditious access to a broad range of polysubstituted α,β-unsaturated ketones with excellent atom economy and regioselectivity.
- Li, Hong-Shuang,Guo, Guili,Zhang, Rui-Ze,Li, Fei
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supporting information
p. 5040 - 5043
(2018/08/24)
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- Catalytic enantioselective allyl-allyl cross-coupling with a borylated allylboronate
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Catalytic enantioselective allyl-allyl cross-coupling of a borylated allylboronate reagent gives versatile borylated chiral 1,5-hexadienes. These compounds may be manipulated in a number of useful ways to give functionalized chiral building blocks for asymmetric synthesis.
- Le, Hai,Kyne, Robert E.,Brozek, Laura A.,Morken, James P.
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supporting information
p. 1432 - 1435
(2013/07/05)
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- Rabbit 3-hydroxyhexobarbital dehydrogenase is a NADPH-preferring reductase with broad substrate specificity for ketosteroids, prostaglandin D2, and other endogenous and xenobiotic carbonyl compounds
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3-Hydroxyhexobarbital dehydrogenase (3HBD) catalyzes NAD(P) +-linked oxidation of 3-hydroxyhexobarbital into 3-oxohexobarbital. The enzyme has been thought to act as a dehydrogenase for xenobiotic alcohols and some hydroxysteroids, but its physiological function remains unknown. We have purified rabbit 3HBD, isolated its cDNA, and examined its specificity for coenzymes and substrates, reaction directionality and tissue distribution. 3HBD is a member (AKR1C29) of the aldo-keto reductase (AKR) superfamily, and exhibited high preference for NADP(H) over NAD(H) at a physiological pH of 7.4. In the NADPH-linked reduction, 3HBD showed broad substrate specificity for a variety of quinones, ketones and aldehydes, including 3-, 17- and 20-ketosteroids and prostaglandin D2, which were converted to 3α-, 17β- and 20α-hydroxysteroids and 9α,11β- prostaglandin F2, respectively. Especially, α-diketones (such as isatin and diacetyl) and lipid peroxidation-derived aldehydes (such as 4-oxo- and 4-hydroxy-2-nonenals) were excellent substrates showing low Km values (0.1-5.9 μM). In 3HBD-overexpressed cells, 3-oxohexobarbital and 5β-androstan-3α-ol-17-one were metabolized into 3-hydroxyhexobarbital and 5β-androstane-3α,17β-diol, respectively, but the reverse reactions did not proceed. The overexpression of the enzyme in the cells decreased the cytotoxicity of 4-oxo-2-nonenal. The mRNA for 3HBD was ubiquitously expressed in rabbit tissues. The results suggest that 3HBD is an NADPH-preferring reductase, and plays roles in the metabolisms of steroids, prostaglandin D2, carbohydrates and xenobiotics, as well as a defense system, protecting against reactive carbonyl compounds.
- Endo, Satoshi,Matsunaga, Toshiyuki,Matsumoto, Atsuko,Arai, Yuki,Ohno, Satoshi,El-Kabbani, Ossama,Tajima, Kazuo,Bunai, Yasuo,Yamano, Shigeru,Hara, Akira,Kitade, Yukio
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p. 1366 - 1375
(2013/11/19)
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- Structure-Activity relationship of aliphatic compounds for nematicidal activity against pine wood nematode (Bursaphelenchus xylophilus)
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Nematicidal activity of aliphatic compounds was tested to determine a structure-activity relationship. There was a significant difference in nematicidal activity among functional groups. In a test with alkanols and 2E-alkenols, compounds with C8-C11 chain length showed 100% nematicidal activity against pine wood nematode, Bursaphelenchus xylophilus, at 0.5 mg/mL concentration. C6-C10 2E-alkenals exhibited >95% nematicidal activity, but the other compounds with C 11-C14 chain length showed weak activity. Nematicidal activity of alkyl acetates with C7-C11 chain length was strong. Compounds belonging to hydrocarbons, alkanals, and alkanoic acetates showed weak activity at 0.5 mg/mL concentration. Nematicidal activity of active compounds was determined at lower concentrations. At 0.25 mg/mL concentration, whole compounds except C8 alkanol, C8 2E-alkenol, and C7 alkanoic acid showed >80% nematicidal activity. C 9-C11 alkanols, C10-C11 2E-alkenols, C8-C9 2E-alkenals, and C9-C10 alkanoic acids showed >80% nematicidal activity at 0.125 mg/mL concentration. Only C11 alkanol exhibited strong nematicidal activity at 0.0625 mg/mL concentration, the lowest concentration that was tested. 2010 American Chemical Society.
- Seo, Seon-M.I.,Junheon, Kim,Eunae, Kim,Park, Hye-M.I.,Kim, Young-Joon,Park, I.L.-Kwon
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experimental part
p. 1823 - 1827
(2010/09/09)
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- Titanocene-promoted eliminations on epoxy alcohols and epoxy esters
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The reaction of a series of 2,3-epoxy alcohols and the corresponding formates, acetates, and benzoates promoted by Cp2TiCl has been studied. The different outcome of the reaction of epoxy derivatives has been rationalized in terms of mechanistically biased processes. After homolytic oxirane cleavage, four main types of reaction were found: dehydroxylation, decarboxylation, dehydrogenation, and deoxygenation. The reaction products varied according to the substitution pattern. The radical nature of these eliminations is demonstrated.
- Fernandez-Mateos, Alfonso,Madrazo, Soledad Encinas,Teijon, Pablo Herrero,Gonzalez, Rosa Rubio
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supporting information; experimental part
p. 856 - 861
(2010/04/05)
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- Total synthesis of microcarpalide
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An efficient, convergent approach for the total synthesis of microcarpalide (1) is described. The synthetic strategy features the Sharpless asymmetric dihydroxylation, regioselective epoxide opening with various nucleophiles such as a lithium acetylide and cuprates derived from the vinyl stannane and the vinyl iodide for the construction of a C7-C8 trans-double bond and Yamaguchi macrolactonization as the key steps.
- Kumar, Pradeep,Naidu, S. Vasudeva
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p. 4207 - 4210
(2007/10/03)
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- Acetyl chloride-ethanol brings about a remarkably efficient conversion of allyl acetates into allyl chlorides
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AcCl-EtOH transforms primary and secondary allyl acetates into allyl chlorides that retain the olefinic bond in the more stable position. Whereas secondary allyl alcohols also react with almost the same efficacy as the acetates, the reactions of primary allyl alcohols that possess 1, 2-disubstituted alkenes are very slow. The products are isolated in high state of purity simply by removal of the volatiles.
- Yadav, Veejendra K.,Ganesh Babu
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p. 9111 - 9116
(2007/10/03)
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- Mesyloxy-group migration as the stereoselective preparation method of various functionalized olefins and its reaction mechanism
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It was demonstrated that mesylation of appropriate γ,γ-difluorinated allylic alcohols under usual conditions furnished the corresponding α,γ-difluorinated allylic mesylates, possibly by way of 1,3-mesyloxy-group migration after formation of the expected "normal" intermediates, γ,γ-difluorinated allylic mesylates. This rearrangement was conveniently applied to the construction of trisubstituted allylic alcohols, α,β-unsaturated esters, amides, or ketones in good to excellent chemical yields with exclusive E selectivities.
- Yamazaki, Takashi,Hiraoka, Shuichi,Sakamoto, Johei,Kitazume, Tomoya
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p. 743 - 746
(2007/10/03)
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- A simple synthetic method for chiral 1,2-epoxides and the total synthesis of a chiral pheromone epoxide
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Chiral 1,2-epoxyalkan-3-ol tosyl esters 4a-h were successfully synthesized from alkynols or allyl chlorides in three steps using Sharpless AD reaction as a key step in good yields. The chiral insect pheromone epoxide (6Z,9S,10R)-9,10-epoxyhenicos-6-ene 9 was thus smoothly synthesized from the corresponding key intermediate 4g.
- Zhang, Zhi-Bo,Wang, Zhi-Min,Wang, Yu-Xiu,Liu, Huan-Quan,Lei, Gui-Xin,Shi, Min
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- A facile synthetic method for chiral 1,2-epoxides and the total synthesis of chiral pheromone epoxides
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Chiral 1,2-epoxy-3-alkanol tosylates were successfully synthesized from alkynols in three steps using the Sharpless AD reaction as a key step in good yields. Two chiral insect pheromone epoxides were smoothly obtained from the corresponding key intermediate.
- Zhang, Zhi-Bo,Wang, Zhi-Min,Wang, Yu-Xiu,Liu, Huan-Quan,Lei, Gui-Xin,Shi, Min
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p. 837 - 840
(2007/10/03)
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- REDUCTION OF α-ALKYNYL EPOXIDES
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The catalytic hydrogenation of 2-(1-heptynyl)oxirane leads preferentially to 3(Z)-nonen-1-ol, whereas the reduction of this epoxide with lithium in ethylamine gives 3(E)-nonen-1-ol.In both cases the main products are accompanied by the isomeric 2-nonen-1-ols.
- Vasil'ev, A. A.
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- A SIMPLE PROCEDURE FOR THE SYNTHESIS OF THREE-CARBON HOMOLOGATED BORONATE ESTERS AND TERMINAL ALKENES VIA NUCLEOPHILIC DISPLACEMENT IN α-HALOALLYLBORONATE ESTER
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The transfer reactions of α-haloallylboronate ester 1 with representative organolithium and Grignard reagents provide α-alkyl- or α-aryl-substituted allylboronate esters, readily converted into three-carbon homologated boronate esters and terminal alkenes.
- Brown, Herbert C.,Rangaishenvi, Milind V.
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p. 7115 - 7118
(2007/10/02)
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- Chemistry of Fruit Flies. Composition of the Rectal Gland Secretion of (Male) Dacus cucumis (Cucumber Fly) and Dacus halfordiae. Characterization of (Z,Z)-2,8-Dimethyl-1,7-dioxaspiroundecane
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Combined gas chromatography-mass spectrometry and synthesis have established that the major components of the rectal gland secretion of adult male cucumber flies (Dacus cucumis) are the E,E, E,Z, and Z,Z diastereomers of 2,8-dimethyl-1,7-dioxaspiroundecane, which have been synthesized utilizing organomercury chemistry from 1,10-undecadien-6-one.The thermodynamically least stable Z,Z diastereomer has been characterized for the first time, by 1H and 13C NMR measurements and mass spectrometry.Minor amounts of 3-hydroxy-2,8-dimethyl-1,7-dioxaspiroundecane and various derivatives of the 1,6-dioxaspirodecane and 1,7-dioxaspirododecane systems are also present. 1,3-Nonanediol occurs in significant amounts, and both enantiomers have been acquired by Sharpless asymmetric epoxidation of (E)-2-nonen-1-ol followed by Red-Al (Aldrich) reduction of the chiral epoxy alcohols.Chiral gas chromatographic analysis of the diols (as their cyclic carbonates) has demonstrated that the natural material is the R-(-) enantiomer.Natural (E,Z)-2,8-dimethyl-1,7-dioxaspiroundecane is shown to be racemic, whereas the more abundant E,E diastereomer is enantiomerically highly pure, possessing the 2S,6R,8S configuration.The major volatile component of the rectal gland secretion of male Dacus halfordiae (Tryon) is also (E,E)-2,8-dimethyl-1,7-dioxaspiroundecane, with no detectable levels of the E,Z or Z,Z isomers.Other spiroacetals present were 2-ethyl-7-methyl-1,6-dioxaspirodecane and the unusual even carbon-numbered (E,E)-2-ethyl-8-methyl-1,7-dioxaspiroundecane. 6-Oxo-1-nonanol, diethyl succinate, and 2-methyl-6-pentyl-3,4-dihydro-2H-pyran were also identified.
- Kitching, William,Lewis, Judith A.,Perkins, Michael V.,Drew, Richard,Moore, Christopher J.,et al.
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p. 3893 - 3902
(2007/10/02)
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- A NEW SYNTHESIS OF α,β-UNSATURATED ALDEHYDES
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The two carbon homologation of carbonyl compounds to α,β-unsaturated aldehydes is achieved by the Wittig-Horner reaction with N-methoxy N-methyl diethylphosphonoacetamide 1 followed by lithium aluminium hydride reduction.
- Nuzillard, Jean-Marc,Boumendjel, Ahcene,Massiot, Georges
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p. 3779 - 3780
(2007/10/02)
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- Synthesis of the optical antipodes of 4-alkyl-γ-lactones
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Optical antipodes of 4-alkyl-γ-lactones 3 have been prepared by photochemical rearrangement of optically active α,β-epoxy diazomethyl ketones 1 in ethanol to give 4-hydroxy-alkenoates 2, followed by reduction of the alkene bond and subsequent lactonization.The required epoxy diazomethyl ketones 1 were obtained via the following sequence of reactions: alkylation of 2-propyn-1-ol, subsequent reduction to the alkenols 6, Sharpless epoxidation to 2,3-epoxy alcohols 7, oxidation to glycidic esters 8 and finally conversion to diazo ketones 1.The enantiomeric purities range from 84 to 100percent.
- Thijs, Lambertus,Waanders, Peter P.,Stokkingreef, Edwin H. M.,Zwanenburg, Binne
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p. 332 - 337
(2007/10/02)
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- Retentive Stereospecificity in Deoxygenation of Epoxides with Sn-Al Reagents
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Reaction of epoxides with 3SnAlMe3>(1-)*Li(1+) affords β-oxido stannanes which collapse to alkene with overall retention of stereochemistry.The SN2 type ring opening of epoxides by tributylstannyl anion followed by anti elimination of Bu3Sn and OAl-Me3 groups explains the stereochemical results.The method can be succesfully applied to hydroxy epoxides derived from (E)-2-nonen-1-ol.The deoxygenation of epoxides with PhMe2SiAlEt2 also provides olefins of the same geometry as epoxides.
- Matsubara, Seijiro,Nonaka, Tsuyoshi,Okuda, Yasuhiro,Kanemoto, Shigekazu,Oshima, Koichiro,Nozaki, Hitosi
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p. 1480 - 1483
(2007/10/02)
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- Alkene Epoxidation by Iodosylbenzene Catalysed by Porphyrin and Non-porphyrin Iron Complexes: the Importance of the Porphyrin Ligand in Cytochrome P-450 and Heme Model Reactions
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FeCl3 and Fe(acac)3 (acac = acetylacetonato), like Fe(TPP)(Cl) (TPP = tetraphenylporphyrinato), catalyse the epoxidation of styrene and stilbenes and the oxidation of non-1-ene by PhIO; however, several characteristics of the oxidations catalysed by non-porphyrin iron complexes, such as stereospecificity and sensitivity to dioxygen, are very different from those of the corresponding reactions catalysed by Fe(TPP)(Cl).
- Fontecave, Marc,Mansuy, Daniel
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p. 879 - 881
(2007/10/02)
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- ALLYLSELENIDES POSSESSING A TERMINAL DOUBLE BOND FIRST REGIOSELECTIVE SYNTHESIS AND REACTIONS
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Allyl methyl selenides bearing a terminal double bond rearrange in the presence of even a trace of acid, whereas their phenyl analogues, contrary to what has been described, were found to be thermally stable but highly sensitive to light.
- Giamberardino, T. Di,Halazy, S.,Dumont, W.,Krief, A.
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p. 3413 - 3416
(2007/10/02)
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- (Diisopropoxymethylsilyl)methyl Grignard Reagent: A New, Practically Useful Nucleophilic Hydroxymethylating Agent
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The (diisopropoxymethylsilyl)methyl Grignard reagent serves as a new, versatile nucleophilic hydroxymethylating agent of organic halides via the metal-catalyzed cross-coupling and the subsequent oxidative cleavage of the silicon-carbon bond
- Tamao, Kohei,Ishida, Neyoshi,Kumada, Makoto
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p. 2120 - 2122
(2007/10/02)
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- A NEW SYNTHETIC METHOD FOR PELLITORINE
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A stereoselective synthesis of N-isobutyl-E,E-2,4-decadienamide, so called pellitorine is described in which the elimination reaction of acetic acid from 2-acetoxy-E-3-decenenitrile providing 2,4-decadienenitrile in a high yield was used as a key reaction.
- Mandai, Tadakatsu,Gotoh, Jiso,Otera, Junzo,Kawada, Mikio
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p. 313 - 314
(2007/10/02)
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