- Concise Synthesis and Antimicrobial Evaluation of the Guanidinium Alkaloid Batzelladine D: Development of a Stereodivergent Strategy
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Herein, we describe a stereodivergent route to (±)-batzelladine D (2), (+)-batzelladine D (2), (-)-batzelladine D (2), and a series of stereochemical analogues and explore their antimicrobial activity for the first time. The concise synthetic approach enables access to the natural products in a sequence of 8-12 steps from readily available building blocks. Highlights of the synthetic strategy include gram-scale preparation of a late stage intermediate, pinpoint stereocontrol around the tricyclic skeleton, and a modular strategy that enables analogue generation. A key bicyclic β-lactam intermediate not only serves as the key controlling element for pyrrolidine stereochemistry but also serves as a preactivated coupling partner to install the ester side chain. The stereocontrolled synthesis allowed for the investigation of the antimicrobial activity of batzelladine D, demonstrating promising activity that is more potent for non-natural stereoisomers.
- Lin, You-Chen,Ribaucourt, Aubert,Moazami, Yasamin,Pierce, Joshua G.
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- Divinylcarbinol Desymmetrization Strategy: A Concise and Reliable Approach to Chiral Hydroxylated Fatty Acid Derivatives
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By the aid of the catalytic desymmetrization of divinylcarbinol as one-pot asymmetric induction and protection of olefin, asymmetric total syntheses of two chiral hydroxylated fatty acid derivatives were successfully achieved. The desired stereoisomers could be concisely prepared in mild conditions in a highly convergent manner. Thus, this novel strategy can help stereochemical elucidations of natural products, which have difficulties in spectroscopic stereochemical analyses due to their local symmetries in the vicinities of the stereogenic secondary hydroxyl units.
- Sugimoto, Kenji,Kobayashi, Ami,Kohyama, Aki,Sakai, Haruka,Matsuya, Yuji
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p. 3970 - 3980
(2021/03/01)
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- Retro-aza-Michael reaction of an o-aminophenol adduct in protic solvents inspired by natural products
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α,β-Unsaturated carbonyls are reactive group often found in bioactive small molecules. Their non-specific reaction with biomolecules can be the cause of the low efficacy and unexpected side-effects of the molecule. Accordingly, unprotected α,β-unsaturated carbonyls are not often found in drugs. Here, we report that o-aminophenol is a new masking group of α,β-unsaturated ketone, which is inspired by natural products saccharothriolides. o-Aminophenol adduct of α,β-unsaturated ketone, but not those of α,β-unsaturated amide or ester, undergoes a retro-Michael reaction to yield o-aminophenol and the Michael acceptor. This reaction was observed only in protic solvents, such as MeOH and aqueous MeOH. In contrast, o-anisidine was not eliminated from its Michael adduct. o-Aminophenol may be a promising masking tool of highly-reactive bioactive α,β-unsaturated carbonyl compounds.
- Kakeya, Hideaki,Kaneko, Kensuke,Nishimura, Shinichi,Takahashi, Nobuaki,Takenaka, Kei
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- Enantioselective addition of selenosulfonates to α,β-unsaturated ketones
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An organo-catalyzed enantioselective addition of selenosulfonates to α,β-unsaturated ketones was developed for the first time. With a chiral squaramide as an efficient catalyst, the desired α-selenylated ketones were obtained in a good yields with high enantioselectivity up to 89% ee, and good results could be obtained on a gram scale. The products could also be efficiently transformed into useful building blocks with a propenylic stereocenter; the strategy presented in this study may find further applications in organic synthesis.
- Luo, Shilong,Zhang, Nan,Wang, Zhen,Yan, Hailong
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supporting information
p. 2893 - 2901
(2018/05/03)
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- An organocatalyzed Stetter reaction as a bio-inspired tool for the synthesis of nucleic acid-based bioconjugates
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An N-Heterocyclic Carbene (NHC) catalyzed biomimetic Stetter reaction was applied for the first time as a bioconjugation reaction to sensitive nucleoside-type biomolecules to provide original pyrrole linked nucleolipids. A versatile approach allowed the functionalization of thymidine at the three reactive positions (O-5′, O-3′ and N-3) providing a structural diversity oriented synthesis. This strategy was applied to the synthesis of an original glyconucleolipid amphiphile in the hope that the pyrrole aromatic moiety would induce additional self-assembling properties.
- Hamoud, Aladin,Barthélémy, Philippe,Desvergnes, Valérie
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supporting information
p. 1760 - 1769
(2018/03/21)
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- Photoredox Activation of SF6for Fluorination
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We report the first practical use of SF6as a fluorinating reagent in organic synthesis. Photoredox catalysis enables the in situ conversion of SF6, an inert gas, into an active fluorinating species by using visible light. Under these conditions, deoxyfluorination of allylic alcohols is effected with high chemoselectivity and is tolerant of a wide range of functional groups. Application of the methodology in a continuous-flow setup achieves comparable yields to those obtained with a batch setup, while providing drastically increased material throughput of valuable allylic fluoride products.
- McTeague, T. Andrew,Jamison, Timothy F.
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supporting information
p. 15072 - 15075
(2016/11/25)
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- Lewis acid catalyzed synthesis of cyclic carbonates, precursors of 1,2- and 1,3-diols
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An eco-friendly synthesis of cyclic carbonates through a Lewis acid catalyzed cyclization of tert-butyl carbonates is described. These cyclic carbonates are precursors of 1,2- and 1,3-diols, and the developed method was applied to a short synthesis of a diarylheptanoid, (3S,5S)-alpinikatin.
- Cornil, Johan,Gonnard, Laurine,Guerinot, Amandine,Reymond, Sebastien,Cossy, Janine
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supporting information
p. 4958 - 4962
(2014/08/18)
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- Influence of the chemical structure on odor qualities and odor thresholds in homologous series of alka-1,5-dien-3-ones, alk-1-en-3-ones, alka-1,5-dien-3-ols, and alk-1-en-3-ols
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Odor qualities and odor thresholds in air in homologous series of synthesized alk-1-en-3-ols and alka-1,5-dien-3-ols and their corresponding ketones were evaluated by gas chromatography-olfactometry. In the series of the alk-1-en-3-ols and alk-1-en-3-ones the odor quality changed successively from pungent for the compounds with five carbon atoms via metallic, vegetable-like for the six- and seven-carbon odorants to mushroom-like for the compounds with eight and nine carbon atoms. With further increase in chain length the mushroom-like impression decreased and changed to citrus-like, soapy, or herb-like. In both series, two odor threshold minima were found for the six-carbon and also for the eight- and nine-carbon odorants, respectively. In contrast to this, the odor qualities in the series of the (Z)- and (E)-alka-1,5-dien-3-ols and their corresponding ketones did not change significantly with geranium-like, metallic odors and an increasing mushroom-like odor note with increasing chain length. The lowest thresholds were found for the eight- and nine-carbon (Z)-compounds, respectively.
- Lorber, Katja,Schieberle, Peter,Buettner, Andrea
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p. 1025 - 1031
(2014/03/21)
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- Influence of the chemical structure on odor qualities and odor thresholds in homologous series of alka-1,5-dien-3-ones, alk-1-en-3-ones, alka-1,5-dien-3-ols, and alk-1-en-3-ols
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Odor qualities and odor thresholds in air in homologous series of synthesized alk-1-en-3-ols and alka-1,5-dien-3-ols and their corresponding ketones were evaluated by gas chromatography-olfactometry. In the series of the alk-1-en-3-ols and alk-1-en-3-ones the odor quality changed successively from pungent for the compounds with five carbon atoms via metallic, vegetable-like for the six- and seven-carbon odorants to mushroom-like for the compounds with eight and nine carbon atoms. With further increase in chain length the mushroom-like impression decreased and changed to citrus-like, soapy, or herb-like. In both series, two odor threshold minima were found for the six-carbon and also for the eight- and nine-carbon odorants, respectively. In contrast to this, the odor qualities in the series of the (Z)- and (E)-alka-1,5-dien-3-ols and their corresponding ketones did not change significantly with geranium-like, metallic odors and an increasing mushroom-like odor note with increasing chain length. The lowest thresholds were found for the eight- and nine-carbon (Z)-compounds, respectively.
- Lorber, Katja,Schieberle, Peter,Buettner, Andrea
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p. 1025 - 1031
(2015/04/22)
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- The effect of encapsulated Zn-POM on the catalytic activity of MIL-101 in the oxidation of alkenes with hydrogen peroxide
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Zinc monosubstituted Keggin heteropolyanion [PZnMo2W 9O39]5- was electrostatically bound to nanocages of MIL-101 polymer matrix. The Zn-POM@MIL-101 catalyst was characterized by XRD, N2 adsorption, atomic absorption (AAS), and FT-IR spectroscopic methods. The catalytic activity of the new composite material, Zn-POM@MIL-101, was assessed in the oxidation of alkenes using aqueous hydrogen peroxide as oxidant. Zn-POM@MIL-101/H2O2 catalytic system demonstrated good catalytic activity in the oxidation reactions. Zn-POM@MIL-101 was reusable for three catalytic cycles. While the MIL-101 matrix is an active catalyst in these oxidation reactions, the presence of Zn-POM significantly changed the selectivity and reaction times. Copyright
- Saedi, Zahra,Tangestaninejad, Shaharm,Moghadam, Majid,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj
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experimental part
p. 463 - 473
(2012/05/20)
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- Synthesis and characterization of supported heteropolymolybdate nanoparticles between silicate layers of Bentonite with enhanced catalytic activity for epoxidation of alkenes
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A new heterogeneous catalyst (PVMo/Bentonite) consisting of vanadium substituted heteropolymolybdate with Keggin-type structure Na 5[PV2Mo10O40]·14H 2O (PVMo) supported between silicate layers of bentonite has been synthesized by impregnation method and characterized using X-ray diffraction, Fourier-transformed infrared spectroscopy, scanning electron microscopy, UV-vis diffuse reflectance spectroscopy, transmission electron microscopy and elemental analysis. X-ray diffraction and scanning electron microscopy analysis indicated that PVMo was finely dispersed into layers of bentonite as support. The PVMo/Bentonite used as an efficient heterogeneous catalyst for epoxidation of alkenes. Various cyclic and linear alkenes were oxidized into the corresponding epoxides in high yields and selectivity with 30% aqueous H2O 2. The catalyst was reused several times, without observable loss of activity and selectivity. The obtained results showed that the catalytic activity of the PVMo/Bentonite was higher than that of pure heteropolyanion (PVMo).
- Salavati, Hossein,Rasouli, Nahid
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scheme or table
p. 1853 - 1859
(2011/11/05)
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- Zirconia-supported Keggin phosphomolybdovanadate nanocomposite: A heterogeneous and reusable catalyst for alkene epoxidation under thermal and ultrasonic irradiation conditions
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Keggin phosphomolybdovanadate, PVMo, was supported on a zirconia matrix by the wet impregnation method. The phase and chemical structure, optical absorption, surface physicochemical properties and morphology of PVMo-ZrO 2 composite were studied by X-ray diffraction (XRD) technique, FT-IR and diffuse reflectance UV-vis spectroscopic (DR UV-vis) methods, and scanning electron microscopy (SEM), which indicated that the primary Keggin structure has remained intact after formation of the composite. Moreover, the obtained nanocomposite was used as an efficient catalyst of olefins under reflux and ultrasonic irradiation conditions. The catalyst was reused several times, without observable loss of activity and selectivity. Indeed, the catalytic activity of the PVMo-ZrO2 was compared with pure Keggin phosphomolybdovanadate.
- Salavati, Hossein,Tangestaninejad, Shahram,Moghadam, Majid,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj
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experimental part
p. 588 - 596
(2012/05/20)
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- Sonocatalytic oxidation of olefins catalyzed by heteropolyanion-montmorillonite nanocomposite
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A Keggin-type heteropolyanion compound (HPO) was doped within the montmorillonite (MMT) structure by impregnation method. The synthesized catalyst was characterized by FT-IR, XRD, UV-vis, CV, SEM and elemental analysis. Based on chemical adsorption between HPO, and hydroxyl surface groups, HPOs nanoparticles were successfully located on the MMT. Moreover, the obtained nanocomposite was found as an efficient catalyst for oxidation of hydrocarbons under reflux and ultrasonic irradiation conditions.
- Salavati, Hossein,Tangestaninejad, Shahram,Moghadam, Majid,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj
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experimental part
p. 145 - 152
(2010/11/18)
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- Sonocatalytic epoxidation of alkenes by vanadium-containing polyphosphomolybdate immobilized on multi-wall carbon nanotubes
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A Keggin type polyoxometalate (POM) has been immobilized in the unique network structure of multi-wall carbon nanotubes (CNTs). The vanadium-containing polyphosphomolybdate (PVMo) supported on CNTs, which was prepared by a one-step solid-state reaction, was characterized by FT-IR, XRD, SEM and elemental analyses. These uniform nanoparticles have an average size 20-30 nm. Furthermore, due to the chemical interaction between PVMo and carboxylic acid groups, PVMo nanoparticles were successfully immobilized on the CNTs. Moreover, the obtained composite was found as an efficient catalyst for oxidation of hydrocarbons under reflux and ultrasonic irradiation (US) conditions.
- Salavati, Hossein,Tangestaninejad, Shahram,Moghadam, Majid,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj
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experimental part
p. 453 - 459
(2010/12/25)
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- Titanocene(II)-promoted cross-coupling of unsaturated compounds
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Vinyl pivalate in the presence of the titanocene(II) reagent Cp 2Ti[P(OEt)3]2 reacts both with nonpolar C≡C triple bonds and with polar C=O double bonds, to produce conjugated dienes and allylic alcohols, respectively. Similar alkenylation also takes place when (Z)-alkenyl sulfones are treated with alkynes and carbonyl compounds. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Ogata, Akitoshi,Nemoto, Masami,Arai, Koutarou,Kobayashi, Kenji,Tsubouchi, Akira,Takeda, Takeshi
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p. 878 - 880
(2007/10/03)
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- The carbon-silicon bond cleavage of organosilicon compounds in supercritical water
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Arylsilanes, alkenylsilanes, allylic silanes, and alkylsilanes were found to undergo extremely facile and rapid C-Si bond cleavage in supercritical water. Rapid C-Si bond cleavage occurred even with robust unactivated tetraalkylsilanes. The control experiments revealed the dramatic difference between the supercritical and subcritical conditions, and that between supercritical water and supercritical methanol, attesting to a unique reactivity of supercritical water in C-Si bond cleavage. It was also found that acids, such as HCl, HBr, and H2SO4, promote C-Si bond cleavage in supercritical water.
- Itami, Kenichiro,Terakawa, Koji,Yoshida, Jun-Ichi,Kajimoto, Okitsugu
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p. 2071 - 2080
(2007/10/03)
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- Efficient and rapid C-Si bond cleavage in supercritical water
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Arylsilanes, alkenylsilanes, allylic silanes, and alkylsilanes were found to undergo extremely facile and rapid C-Si bond cleavage in supercritical water. The rapid C-Si bond cleavage occurred even with robust unactivated tetraalkylsilanes. The control experiments revealed the dramatic difference between supercritical and subcritical conditions and that between supercritical water and supercritical methanol, attesting to a unique reactivity of supercritical water in C-Si bond cleavage. Copyright
- Itami, Kenichiro,Terakawa, Koji,Yoshida, Jun-ichi,Kajimoto, Okitsugu
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p. 6058 - 6059
(2007/10/03)
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- Enantiospecific synthesis of the phospholipase A2 inhibitor (-)-cinatrin B
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The first enantiospecific synthesis of phospholipase A2 (PLA2) inhibitor (-)-cinatrin B (2) from the D-arabinose derivative 9 is described. The spirolactone system was formed by an Ireland-Claisen rearrangement of the allyl ester 8 followed by hydrolysis and stereoselective iodolactonization. The stereoselectivity of the rearrangement was controlled by the asymmetry in the allylic alcohol fragment. Ester (S)-8 gave the desired rearrangement product 7 and the epimer 13 in high yield as a 73:27 ratio, respectively. The final stereocenter at C2 was introduced via a chelation-controlled addition of the Grignard reagent derived from trimethylsilylacetylene to α-hydroxy ketone 6. Transformation of the terminal alkyne into the methyl ester 21 followed by acetal hydrolysis and selective lactol oxidation afforded cinatrin B methyl ester (22). Base hydrolysis and acid-induced relactonization then gave (-)-cinatrin B (2).
- Cuzzupe, Anthony N.,Di Florio, Romina,Rizzacasa, Mark A.
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p. 4392 - 4398
(2007/10/03)
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- Conformational mobility and preferences of Allyl-type organometallic intermediates : Dodec-2-eny lpotassium
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Alk-2-enylpotassium compounds having the endo conformation are synthetically very valuable precursors of (Z)-olefinic derivatives substituted at the outward allylic position. They may be generated by "stereoconservative" metalation of the readily available (Z)-alk-2-enes by using the superbasic mixture of butyllithium and potassium terf-butoxide or by metalation under similar conditions of stereorandom mixtures of alk-2-enes or alk-1-enes followed by torsional isomerization of the concomitantly formed exo conformers to the thermodynamically more stable endo species. The principal factors that dictate the rate and the extent of the endo/exo equilibration are the substrate geometry, the solvent, the temperature, the reagent stoichiometry, and catalysis Keywords: Torsional (ZIE) isomerization / Selectivity, regio- and stereo- / Allylsilanes / Allylic oxidation VCH Verlagsgescllschaft mbH.
- Franzini, Livia,Moret, Etienne,Schlosser, Manfred
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- Glycosyl Imidates, 35. - Synthesis of a Cerebroside Having a (4E,8E)-Sphingadienine Moiety from Tetragonia tetragonoides with Antiulcerogenic Activity
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The natural cerebroside 1a possessing antiulcerogenig activity and its diastereomer 1b were readily synthesized by the azidosphingosine glycosylation method.The requied (4E,8E)-azidosphingadienine 12 was obtained from (4E)-tetradecenyl bromide (7) and 2,4-O-benzylidene-D-threose (9) by Wittig reaction, subsequent azide introduction and benzylidene group removal.For the glucosylation the corresponding 3-O-benzoyl derivative 15 was prepared; it provided with the trichloroacetimidate 16 as glucosyl donor the desired β-D-glucopyranosyl derivative 17 in high yield.Deprotection and azido group reduction afforded compound 19 with a free amino group.N-Acylation with both enantiomers of 2-hydroxypalmitic acid (using the derivatives 20 a,b) yielded after deacetylation compounds 1a and 1b, respectively.
- Baer, Thomas,Schmidt, Richard R.
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p. 669 - 674
(2007/10/02)
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- Reactions of (2S)-1-Arenesulfonyl-2-alkanol Dianions with Aldehydes. Application to the Synthesis of Enantiomerically Pure (3S)-1-Alken-3-ols and (2E,4S)-4-hydroxy-2-alkenenitriles
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Enantiomerically pure (2S)-1-arenesulfonyl-2-alkanols (1) were prepared by yeast reduction of 1-arenesulfonyl-3-chloro-2-propanones, followed by epoxydation and alkylation.Reaction of dianions of 1 with aldehydes occurred at the pro(R) position of C(1) to give 1,3-diols, which were converted to (3S)-1-alken-3-ols or (2E,4S)-4-hydroxy-2-alkenenitriles in 100percent e.e.
- Tanikaga, Rikuhei,Hosoya, Ken,Kaji, Aritsune
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p. 829 - 832
(2007/10/02)
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- PALLADIUM CATALIZED OXIDATION OF ALLYLSILANES WITH U.V. LIGHT AND MOLECULAR OXIGEN
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Photolysis of oxygenated acetone solutions of allylsilanes containing small amounts of palladium led to α,β-ethylenic alcohols, aldehydes or ketones.Efficient regiospecific oxidation can be observed when the allylsilane was substituted by an arylsulphonyl group.
- Riahi, A.,Cossy, J.,Muzart, J.,Pete, J. P.
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p. 839 - 842
(2007/10/02)
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- Regioselective Synthesis of Allyltrimethylsilanes from Allylic Halides and Allylic Sulfonates. Application to the Synthesis of 2,3-Bis(trimethylsilyl)alk-1-enes
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The preparation of allyltrimethylsilanes by regioselective pathways is described.Treatment of (E)-1-chloro-2-alkenes with a reagent prepared from 1 equiv each of trimethylsilyllithium and copper(I) iodide in hexamethylphosphoramide to presumably form a (trimethylsilyl)copper reagent affords 3-(trimethylsilyl)-1-alkenes in good to excellent yields with a high regioselectivity.Treatment of these same 1-chloro-2-alkenes with (trimethylsilyl)lithium alone without added copper(I) iodide yields only (E)-1-(trimethylsilyl)-2-alkenes.A single allylic halide thus yields two regioisomeric allyltrimethylsilanes by proper choice of reaction conditions.The reaction of a variety of allylic sulfonates with (trimethylsilyl)copper has also been investigated.The mesylates of 2 deg and 3 deg allylic alcohols yield mixtures of isomeric allyltrimethylsilanes in which the 1-(trimethylsilyl)-2-alkenes predominate.With geraniol, the mesylate was prepared in situ and allowed to react with (trimethylsilyl)copper to afford two isomeric allyltrimethylsilanes in which the 3-(trimethylsilyl)-1-alkene predominates.Finally, these reactions have also been used to prepare a variety of 2,3-bis(trimethylsilyl)alk-1-enes, a class of unsaturated organosilanes which has received little attention in the literature.
- Smith, Janice Gorzynski,Drozda, Susan E.,Petraglia, Susan P.,Quinn, Nina R.,Rice, Elizabeth M.,et al.
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p. 4112 - 4120
(2007/10/02)
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