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Asymmetric Synthesis of (R)-Fluoxetine: A Practical Approach Using Recyclable and in-situ Generated Oxazaborolidine Catalyst 总被引:1,自引:0,他引:1
A practical route for the synthesis of (R)-fluoxetine•HCl (ee=96%) in 56% overall yield was described. The key intermediate (R)-3-chloro-1-phenyl-1-propanol was obtained by the asymmetric reduction of prochiral 3-chloropropiophenone using in-situ generated oxazaborolidine catalyst derived from (S)-α,α-diphenylprolinol. The chiral procatalyst (S)-α,α-diphenylprolinol was recovered quantitatively and recycled. An improved practical synthesis of (S)-α,α-diphenylprolinol was also discussed. 相似文献
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A practical synthesis of (R)‐4‐(benzyloxy)‐3‐methylbutanenitrile, a potential chiral building block, from the corresponding α‐keto ester in high yield and large scale was presented. 相似文献
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Zhongtao Wu Prof. Dr. Syuzanna R. Harutyunyan Prof. Dr. Adriaan J. Minnaard 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(44):14250-14255
Based on the asymmetric copper‐catalyzed 1,2‐addition of Grignard reagents to ketones, (R,R,R)‐γ‐tocopherol has been synthesized in 36 % yield over 12 steps (longest linear sequence). The chiral center in the chroman ring was constructed with 73 % ee by the 1,2‐addition of a phytol‐derived Grignard reagent to an α‐bromo enone prepared from 2,3‐dimethylquinone. 相似文献
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Panaxynol1,asacommonconstituentofmanyplantparts',wasfirstdescribedbyTakahashietal.2in1964asaconstituentofPanaxyginseng.C.A.MeyershowedinhisBioassayshowedthatpanaxynolhadselectiveinvitrocytotoxicityagainstL-1210',MKI,B-16,andL-929cancercelllinescomparedtonormalcellcultures4.TheabsoluteconfigurationhadbeenestablishedbyLarsenetal.5tobe3R.Hereinwereportthefirsttotalstereoselectivesynthesisofpanaxynol(l).C'-CIafragmentofpanaxynol1wasobtainedaccordingtothefollowingsequencefReagentsandconditio… 相似文献
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Enantiospecific Synthesis of (R)‐3‐Amino‐4‐(2,4,5‐trifluorophenyl)butanoic Acid Using (S)‐Serine as a Chiral Pool 下载免费PDF全文
Aytekin Köse Özlem Gündoğdu Derya Aktaş Meryem Fıstıkçı Ramazan Altundaş Hasan Seçen Yunus Kara 《Helvetica chimica acta》2015,98(2):260-266
Starting from (S)‐serine, a new method was developed for the synthesis of the β‐amino acid part of sitagliptin in ten steps and with an overall yield of 30%. The crucial step of the synthesis was the ring opening of N‐ and O‐protected (R)‐aziridin‐2‐methanol with (2,4,5‐trifluorophenyl)magnesium bromide to give N‐ and O‐protected (R)‐2‐amino‐3‐(2,4,5‐trifluorophenyl)propan‐1‐ol. 相似文献
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An Efficient Stereoselective Total Synthesis of Bioactive (3R,5R)‐1‐(4‐Hydroxyphenyl)‐7‐phenylheptane‐3,5‐diol via Asymmetric Aldol Reaction 下载免费PDF全文
An efficient stereoselective total synthesis of (3R,5R)‐1‐(4‐hydroxyphenyl)‐7‐phenylheptane‐3,5‐diol ( 1 ) is reported based on the Mukaiyama aldol reaction. The total synthesis of compound 1 was accomplished with 30% overall yield in simple eight steps from commercially available trans‐cinnamaldehyde. 相似文献
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Parigi Raghavendar Reddy Chithaluri Sudhakar Jayprakash Narayan Kumar Biswanath Das 《Helvetica chimica acta》2013,96(2):289-295
The first stereoselective total synthesis of the naturally occurring anti‐emetic diarylheptanoid (3R,5R)‐1‐(4‐hydroxyphenyl)‐7‐phenylheptane‐3,5‐diol ( 1 ) was accomplished starting from 4‐hydroxybenzaldehyde and involving a Sharpless kinetic resolution and an asymmetric epoxidation as the key steps (Scheme 2). The enantiomer 1a of this compound was also simultaneously prepared. 相似文献
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Mohamed A. Abdelwahab Elisa Martinelli Michele Alderighi Elizabeth Grillo Fernandes Syed Imam Andrea Morelli Emo Chiellini 《Journal of polymer science. Part A, Polymer chemistry》2012,50(24):5151-5160
A novel triblock copolymer PS–PHB–PS based on the microbial polyester Poly[(R)‐3‐hydroxybutyrate)] (PHB) and poly(styrene) (PS) was prepared to be used as compatibilizer for the corresponding PHB/PS blends. It was prepared in a three‐step procedure consisting of (i) transesterification reaction between ethylene glycol and a high‐molecular‐weight PHB, (ii) synthesis of bromo‐terminated PHB macroinitiator, and (iii) atom transfer radical polymerization polymerization of styrene initiated by the PHB‐based macroinitiator. Fourier transform infrared, gel permeation chromatography, 1H‐, and 13C‐NMR spectroscopies were used to determine the molecular structure and/or end‐group functionalities at each step of the procedure. Although thermogravimetric analysis showed that the block copolymer underwent a stepwise thermal degradation and had better thermal stability than their respective homopolymers, differential scanning calorimetry displayed that the PHB block in the copolymer could not crystallize, and thus generating a total amorphous structure. Atomic force microscopy images indicated that the block copolymer was phase segregated in a well‐defined morphological structure with nanodomain size of ~40 nm. Contact angle measurements proved that the wettability properties of the block copolymer were in between those of the PHB and PS homopolymers. Blends analyzed for their morphology and thermal properties showed good miscibility and had well‐defined morphological features. Polymer blends exhibited lower crystallinity and decreased stiffness which was proportional to the amount of compatibilizer content in the blends. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
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Zhen‐Feng Chen Ling Huang Hong Liang Rui‐Xiang Hu Shao‐Ming Shi Hoong‐Kun Fun 《应用有机金属化学》2003,17(11):879-880
The structure of Cd(phen)(indole‐3‐acetato)2 has twofold symmetry and features a six‐coordinated distorted octahedral geometry around cadmium(II), defined by an N2O4 donor set, with Cd–O distances ranging from 2.214(3) to 2.526(3) Å. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
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Asymmetric Henry reactions of aldehydes with various nitroalkanes catalyzed by copper(II) complexes of novel chiral N‐monoalkyl cyclohexane‐1,2‐diamines 下载免费PDF全文
A number of novel chiral diamines 3 , (1R,2R)‐N‐monoalkylcyclohexane‐1,2‐diamines, were designed and synthesized from trans‐cyclohexane‐1,2‐diamine and applied to the catalytic asymmetric Henry reaction of benzaldehyde and nitromethane to provide β‐nitroalcohol in high yield (up to 99%) and good enantiomeric excess (up to 89%). By using ligand (1R,2R)‐N1‐(4‐methylpentan‐2‐yl)cyclohexane‐1,2‐diamine ( 3g ), the reaction was optimized in terms of the metal ion, temperature, solvent and base. Further experiments indicated that the complex, 3g –Cu(OAc)2, was an efficient catalyst in the asymmetric Henry reaction between different aldehydes and nitromethane, and the desired products have been obtained with high chemical yields (up to 99%) and high enantiomeric excess (up to 93%). The optimized catalyst promoted the diastereoselective Henry reaction of various aldehyde substrates and nitroalkane, which gave the corresponding anti‐selective adduct with up to 99% yield and 83:17 anti/syn selectivity. Upon scaling up to gram quantities, the β‐nitroalcohol was obtained in good yield (96%) with excellent selectivities (93% ee). The chiral induction mechanism was tentatively explained on the basis of a previously proposed transition‐state model. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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The lead atom in Pb(phen)(IA)2 is in a heavily distorted square pyramidal geometry surrounded by an N2O3 donor set with Pb? O distances ranging from 2.354(5) to 2.726(5) Å. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献