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1.
Abstract (R)-(?)-β-Cuparenone has been synthesized from (S)-(+)-acid-2 obtained via resolution of the racemic acid. Two of the noteworthy steps are (a) repeated methylation of ester (+)-8 with LDA/MeI to furnish (+)-10 and (b) the reaction of 12, having two neopentyl units with NaCN. 相似文献
2.
《中国化学快报》1997,(11)
(-)-Methyl(4R,5SloR)-l4-methoxyPodocmpa-8,ll,l3-triene-l9-oate(I)isthekeyintermediateforsynthesesofditerpenoidssuchaskaurenoicacid(3),kaur-l6-en-l9-ol(4),monoginol(5)('),aswellasC,,-diterpenealkaloidssuchasveachine(6),garryine(7)andatisine(8)(=).TheracemicsynthesisofthisintermediatewasdonebyK.Morietar'),butthechiralsynthesishasnotbeenreported.Herewepresentthechiralsynthesisofthiskeyintermediatefrom(R)-(+)-2-methyl-2-(2'-nitrovinyl)-5-vaierolactone(2).2wassynthesizedaccordingtoliterattirmeth… 相似文献
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4.
A class of chiral ketone was synthesized for asymmetric epoxidation. High ee values have been obtained for a number of cis olefin and trans olefin. The epoxidation was stereospecific with no isomerizatiom observed in the epoxidation of acyclic system. Encourageingly high ee value has also been obtained for a number of terminal olefins. Mechanistic studies show that electronic interactions play an important role in the stereodifferentiation. O O O O O O NBoc O O t-BuO2CH2CN O O O … 相似文献
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6.
Synthesis of a New Aryl Ether Ketone Polymer 总被引:1,自引:0,他引:1
SemicrystallinearyletherketonepolymerssuchasPEEKbelongtoaclassofmaterialsknownasengineeringthermoplastics.PEEKexhibitsarelativelyhighdegreeofcrystallinityandameltingpoint(T.)of335"C.Ontheotherhand,PEEKsuffersfrompoorcreepbehavioraboveitsrelativelylowglasstransitiontemperature(T,)of143"C.Therefore,thesynthesisofnewvariantsisthefocusofmuchresearchl'2.Thesenewvariantsareusuallysemicrystallineinnatureandexhibithighmeltingpoints.Thisresultsinprocessingdifficulties,whichhascreatedaneedforpoly… 相似文献
7.
In previous work from our laboratory, we demonstrated that α-carbonyl radical cyclization reactions can serve efficiently as key steps in total synthesis of natural products.1 In this presentation,we report the total synthesis of (-)-α-pinguisene from enone 1 via α-carbonyl radical cyclization. 相似文献
8.
V. Salas-Reyes 《合成通讯》2013,43(12):2187-2199
S-(+)-γ-hydroxymethyl-gM-butyrolactone has been synthesized from D-ribonolactone as chiral template. 相似文献
9.
HUANG Xi-He SHENG Tian-Lu XIANG Sheng-Chang FU Rui-Biao HU Sheng-Min LI Ya-Min WU Xin-Tao 《结构化学》2007,26(2)
The hydrothermal reaction of 1,2-dicyanobenzene with NaN3 in the presence of CuCl2, 2,2′-bipyridine and H2O affords a novel dinuclear copper(II)-ditetrazolate, [Cu(bpy)- (pdtz)]2 (Hpdtz = 5,5′-1,2-phenylene-ditetrazole, bpy = 2,2′-bipyridine). The pdtz ligand is generated in situ through Sharpless 2+3 cycloaddition reaction. Its crystal structure was deter- mined by single-crystal X-ray diffraction method. The crystal crystallizes in the monoclinic system, space group P21/n with a = 8.2096(16), b = 18.580(4), c = 11.838(2) , β = 103.12(3)o, V = 1758.5(6) 3, Z = 2, Mr = 863.83, Dc = 1.631 g/cm3, F(000) = 876 and μ = 1.272 mm-1. In this novel dinuclear structure, the pdtz ligand adopts a peculiar μ2-η1,η2 coordination mode. 相似文献
10.
Abstract Simple and highly efficient synthesis of R(?)-3-benzyl-5 (methoxycarbonylmethylthiomethyl)-hydantoin (7a) from L(+) Cystine (1) is described. 相似文献
11.
Lang Tao SHEN Ting YANG Hong Yu LI Ji HU Zhi Fu LUO National Isotope Center of Engineering Technology China Institute of Atomic Energy Beijing P. O. Box 《中国化学快报》2006,(6)
Iron is indispensable for almost all life forms1. Under iron-deficient environments, microorganisms secrete siderophores to chelate ferric ions and then, transport ferric ions into cells by specific receptor recognitions2,3. Siderophores have many clinica… 相似文献
12.
《中国化学快报》1997,(1)
Thesynthesisofopticallyactivecompoundsisanimportantissueinmodemorgan-icchendstry-7-Terpineol,anaturalproductisolatedfrompetitgrainoil,longleafpineoi1andcaeputoill'J,hasbeenasynthetictargetduringthecourseofourstudiesontheasymmetriccatalisedDiels-AlderreactionlvInthispaper,l-phenylsulfOnyl-3-buten-2-one(l)wasusedasthesulfOnyl-functionalizedche1atingenoneforthesynthesischiral2-Terpineol(5)byaasymmetriccata1isedDiels-Alderreaction.TherouteforthesynthesisofopticallyaCtivea-Terpineo1(5)isshownin… 相似文献
13.
Jiang Yao Zhong Liu Guilan Zhou Changyou Piao Hauri Wu Lanjun Mi Aiqiao 《合成通讯》2013,43(8-9):1087-1090
The stereocontrolled synthesis of (R)—α—amino acids via a double chiral induction in alkylation of the ketimine derived from (+)—camphor and (+)—menthyl glycinate which is a chiral match pair has been studied. (R)—α—amino acids wih high optical purity 80–90% are obtained after hydrolysis of the alkylated products. We find that the chiral match which is the symergistic effect in a double chiral induction is very important to abtain the higher diastereoselectivity for the stereocontrolled synthesis. 相似文献
14.
A chiral salency complex,[Mn(Salency)(H2O)2](PF6)·2H2O 1(Salency =(R,R)-N,N'-bis(salicylidene)-1,2-cyclohexanediamine),has been prepared by the reaction of Mn(CH3COO)3·2H2O with Salency and NH4PF6,and was established by X-ray diffraction techniques.The complex crystallizes in triclinic,space group P1 with a=9.299(8),b=10.012(8),c=13.461(11),α=92.037(15),β=92.974(12),γ=93.530(18)°,V=1248.3(18)3,C20H28F6MnN2O6P,Mr = 592.35,Z=2,Dc=1.038 g/cm3,F(000)=608,μ=0.676 mm-1,the final R=0.0651 and wR=0.1880 for 5260 observed reflections with I 2σ(I). 相似文献
15.
An efficient method was developed for the synthesis of the ketoamino acid 2, a key intermediate in the synthesis of the novel sweet compound, monatin 1. Preparation of 2 entails coupling of a suitably protected indole acetate anion to an aspartic acid derivative. 相似文献
16.
Dr. Tomoya Miura Junki Nakahashi Prof. Dr. Masahiro Murakami 《Angewandte Chemie (International ed. in English)》2017,56(24):6989-6993
(E)-δ-Boryl-substituted anti-homoallylic alcohols are synthesized in a highly diastereo- and enantioselective manner from 1,1-di(boryl)alk-3-enes and aldehydes. Mechanistically, the reaction consists of 1) palladium-catalyzed double-bond transposition of the 1,1-di(boryl)alk-3-enes to 1,1-di(boryl)alk-2-enes, 2) chiral phosphoric acid catalyzed allylation of aldehydes, and 3) palladium-catalyzed geometrical isomerization from the Z to E isomer. As a result, the configurations of two chiral centers and one double bond are all controlled with high selectivity in a single reaction vessel. 相似文献
17.
Thering-openingpolymerization(ROP)reactionplaysanimportantroIeinproductionofhigh-performancethermoplastics'.ThecyclicoligomersofferauniquecombinationoflowmeltviscosityandthecapabilityofachievingveryhighmolecuIarweightinashortreactiontimewithoutthereleaseofvolatilebyproductsandROPhasbeenanactivesubjectofindustrialandacademicresearch.TheROPsofmanycyclicoligomershavebeenachievedviaanionicpolymerizationinthepresenceofthenucleophilicinitiatorsuchascaesiumfluorideandalkaliphenoxides',butusingthe… 相似文献
18.
Dienic acid 5 was transformed into tricyclic ketone 6 in four steps using the cyclopentene annulation of dienic diazoketones. Hydrogenation of 6 under several conditions yielded ketone 7a which was further transformed into β-epiisocomene 4 and epiisocomene 3, contrary to the results previously reported by Samir Chatterjee. 相似文献
19.
The enantioselective chiral l,3,2-oxazaborolidine-catalyzed reduction of prochiralketones by borane has been intensively investigated'-'. Most oxazaborolidine catalystshave been prepared from chiral D-amino alcohols. In our previous study on the catalyststructure-enantioselectivity relationships, we prepared (R)-2-amino-1,l-diphenyl-3~(2naphthyl)-l-propanol I which proved to be a good precursor of chiral catalyst for theenantioselective borane reduction of prochiral ketones4-9. This let'ter d… 相似文献
20.
Li Jing FANG Jin Chun CHEN Guo Jun ZHENG Yu Kun GUAN Yu Lin LI* State Key Laboratory of Applied Organic Chemistry Institute of organic chemistry Lanzhou University Lanzhou 《中国化学快报》2004,(11)
The eudesmane derivative, (-)-10-epi-α-cyperone 1, is widely used as a chiral starting material for the synthesis of other fused-ring sesquiterpenes1. The first synthetic work was reported by Howe and co-workers via condensation of (+)-dihydrocarvone 2 with 1-diethylaminopentan-3-one methiodide in 32% yield2. Previously, our group reported the synthesis of compound 1 by treating ketone 2 with ethyl vinyl ketone (EVK) directly under different conditions1a, but the yields were not satisfacto… 相似文献