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  • Chelation-Assisted C–H and C–C Bond Activation of Allylic Alcohols by a Rh(I) Catalyst under Microwave Irradiation
    Synlett (IF 2.151) Pub Date : 2017-11-16
    Lee, Chang-Hee, Jun, Chul-Ho

    Chelation-assisted Rh(I)-catalyzed ketone synthesis from allylic alcohols and alkenes through C–H and C–C bond activations under microwave irradiation was developed. Aldimine is formed via olefin isomerization of allyl alcohol under Rh(I) catalysis and condensation with 2-amino-3-picoline, followed by continuous C–H and C–C bond activations to produce a dialkyl ketone. The addition of piperidine accelerates the reaction rate by promoting aldimine formation under microwave conditions.

    更新日期:2017-11-19
  • Exploring the Remote Reactivity of π-Extended Carbonyl Compounds: The Vinylogous Alkylidene Malononitrile Activation Strategy
    Synlett (IF 2.151) Pub Date : 2017-11-15
    Curti, Claudio, Sartori, Andrea, Battistini, Lucia, Zanardi, Franca

    The installation of malononitrile into π-extended carbonyl compounds gives rise to vinylogous alkylidene malononitriles (also known as π-extended dicyanovinylidenes), the direct functionalization of which at remote C(sp3) pronucleophilic sites becomes possible and viable. Starting from easily accessible representative polyunsaturated malononitriles, mild conditions were found to directly couple them to complementary enal acceptors. In all cases, the malononitrile handle proved an indispensable (and optionally traceless) activating ingredient for the vinylogous reactions to proceed efficiently and selectively. Merging the vinylogy concept with the malononitrile HOMO-raising activation strategy and complementary organocatalytic activation modalities (i.e. LUMO-lowering iminium ion activation) turned out to be a successful option, as demonstrated by the number of diverse carbocyclic and heterocyclic chiral products that were (stereo)selectively accessed through this chemistry.

    更新日期:2017-11-16
  • Chemoselective Ruthenium-Catalyzed C–O Bond Activation: Orthogonality of Nickel- and Palladium-Catalyzed Reactions for the Synthesis of Polyaryl Fluorenones
    Synlett (IF 2.151) Pub Date : 2017-11-14
    da Frota, Livia C. R. M., Schneider, Cédric, de Amorim, Mauro B., da Silva, Alcides J. M., Snieckus, Victor

    Ruthenium-catalyzed C–O bond activation/arylation of methoxy and O-carbamoyl-substituted fluorenones is reported. Established are new reactions of compound 1 (X = H) to aryl (2) and 1,8-diaryl (3) fluorenones. Orthogonal ruthenium-, palladium- and nickel-catalyzed reactions with Suzuki–Miyaura reactions to afford 1,4-diaryl (4) and 1,4,8-triaryl fluorenones (5) are also described. The ready availability of starting methoxy fluorenones by directed ortho and remote metalation tactics confers facility to the presented reactions which may find application in material science areas. DFT calculations have been performed to rationalize the lack of C–H bond reactivity in the ruthenium-catalyzed reaction.

    更新日期:2017-11-15
  • Easy Access to Isomeric 7-Deazapurine–1,2,3-Triazole Conjugates via SNAr and CuAAC Reactions of 2,6-Diazido-7-deazapurines
    Synlett (IF 2.151) Pub Date : 2017-11-14
    Bucevicius, Jonas, Turks, Maris, Tumkevicius, Sigitas

    A simple and efficient synthesis of isomeric 7-deazapurine–1,2,3-triazole conjugates with amino substituents from readily available 9-alkyl-2,6-diazido-7-deazapurines has been developed using consecutive CuAAC and regioselective nucleophilic substitution reactions of ­azido and 1,2,3-triazole groups with amines.

    更新日期:2017-11-15
  • Iodonium-Induced Cyclization of N-Allenylindoles and N-Allenylpyrroles: An Access to Iododihydropyrido[1,2-a]indoles and Dihydroindolizines
    Synlett (IF 2.151) Pub Date : 2017-11-14
    Grandclaudon, Charlotte, Michelet, Veronique, Toullec, Patrick Y.

    The formation of iodinated dihydropyrido[1,2-a]indoles and dihydroindolizines was achieved by an iodocarbocyclization reaction of N-allenylindoles and N-allenylpyrroles. This transformation proceeded under very mild conditions using N-iodosuccinimide as the electrophilic iodine source to deliver the products via a 6-endo cyclization process. Careful choice of the solvent and concentration were mandatory to obtain the cyclization in good yields.

    更新日期:2017-11-15
  • Investigating the Enantiodetermining Step of a Chiral Lewis Base Catalyzed Bromocycloetherification of Privileged Alkenes
    Synlett (IF 2.151) Pub Date : 2017-11-13
    Böse, Dietrich, Denmark, Scott E.

    The development of catalytic, enantioselective halofunctionalizations of unactivated alkenes has made significant progress in recent years. However, the identification of generally applicable catalysts for wide range of substrates has yet to be realized. A detailed understanding of the reaction mechanism is essential to guide the formulation of a truly general catalyst. Herein, we present our investigations on the enantiodetermining step of a Lewis base catalyzed bromocycloetherification that provides important insights and design criteria.

    更新日期:2017-11-15
  • Intramolecular Aminotrifluoromethanesulfinyloxylation of ω-Aminoalkenes by CF3SO2Na/Pd(OAc)2/PhI(OAc)2/ t BuOCl/PivOH System
    Synlett (IF 2.151) Pub Date : 2017-11-13
    Suzuki, Satoru, Kamo, Tomohiro, Fukushi, Kazunobu, Tokunaga, Etsuko, Sumii, Yuji, Shibata, Norio

    The first example of palladium-catalyzed intramolecular aminotrifluoromethanesulfinyloxylation of unactivated ω-aminoalkenes has been achieved. Reaction conditions are rather unique with a complex consisting of CF3SO2Na/Pd(OAc)2/PhI(OAc)2/ t BuOCl/PivOH to provide 6-endo-cyclized type products with a piperidine skeleton. Yields are moderate, and SO2 is not extruded. This method also provides the first synthesis of 3-trifluoromethanesulfinyloxy piperidine derivatives.

    更新日期:2017-11-15
  • Acid-Mediated C–N Bond Cleavage in 1-Sulfonylpyrrolidines: An Efficient Route towards Dibenzoxanthenes, Diarylmethanes, and Resorcinarenes
    Synlett (IF 2.151) Pub Date : 2017-11-13
    Gazizov, Almir S., Smolobochkin, Andrey V., Anikina, Ekaterina A., Strelnik, Anna G., Burilov, Alexander R., Pudovik, Michail A.

    The rare example of pyrrolidine C–N bond cleavage in 1-sulfonylpyrrolidines in acidic media in the presence of phenols is reported. The reaction proceeds under mild conditions and provides a convenient route to otherwise hardly accessible and previously unknown dibenzoxanthenes, diarylbutanes, and resorcinarenes having a sulfonylamide moiety.

    更新日期:2017-11-15
  • Cluster Preface: Silicon in Synthesis and Catalysis
    Synlett (IF 2.151) Pub Date : 2017-10-27
    Oestreich, Martin

    Martin Oestreich is Professor of Organic Chemistry at the Technische Universität Berlin. His appointment was supported by the Einstein Foundation Berlin. He received his diploma degree with Paul Knochel (Marburg, 1996) and his doctoral degree with Dieter Hoppe (Münster, 1999). After a two-year postdoctoral stint with Larry E. Overman ­(Irvine, 1999–2001), he completed his habilitation with Reinhard ­Brückner (Freiburg, 2001–2005) and was appointed as Professor of Organic Chemistry at the Westfälische Wilhelms-Universität Münster (2006–2011). He also held visiting positions at Cardiff University in Wales (2005) and at The Australian National University in Canberra (2010). Martin Oestreich’s research focuses on silicon in synthesis and catalysis, the theme of the present SYNLETT Cluster. His early work centered on the use of silicon-stereogenic silicon reagents in asymmetric catalysis, and his laboratory continues to employ them as stereochemical probes in mechanistic investigations. His research group made fundamental contributions to catalytic carbon–silicon bond formation with nucleo­philic and, likewise, electrophilic silicon reagents, and Martin Oestreich is probably best known for his work in silylium-ion chemistry. Recent accomplishments of his laboratory include Friedel–Crafts-type C–H silylation, transfer hydrosilylation, and kinetic resolution of alcohols by enantioselective silylation.

    更新日期:2017-11-10
  • Synthesis of Fluorine-Containing Tetraarylanthracenes via Ruthenium-Catalyzed C–O or C–F Arylation and their Crystal Structures
    Synlett (IF 2.151) Pub Date : 2017-11-08
    Izumoto, Akiko, Kondo, Hikaru, Kochi, Takuya, Kakiuchi, Fumitoshi

    Tetraarylanthracenes containing several fluoro groups were synthesized using the ruthenium-catalyzed C–O or C–F arylation with arylboronates and their structural and spectroscopic studies were conducted. The RuH2(CO)(PPh3)3-catalyzed C–O arylation of aromatic ketones was found to be effective for the introduction of aryl groups containing multiple fluoro groups. Anthracenes possessing fluorinated aryl groups were prepared in two steps from 1,4,5,8-tetramethoxyanthraquinone by C–O arylation and reduction of the carbonyl groups. A tetraphenylanthracene containing a fluorinated anthracene moiety was also prepared using C–F phenylation of octafluoroanthraquinone. Single-crystal X-ray diffraction analysis showed that the positions of fluoro groups on the tetraarylanthracenes lead to notable difference in the crystal packing structures. The larger difference between the tetraarylanthracenes was observed in the fluorescence spectra in the solid state than those in chloroform.

    更新日期:2017-11-10
  • Stereospecific Nickel-Catalyzed Borylation of Secondary Benzyl Pivalates
    Synlett (IF 2.151) Pub Date : 2017-11-08
    Martin-Montero, R., Krolikowski, T., Zarate, C., Manzano, R., Martin, R.

    A stereoselective nickel-catalyzed direct borylation of enantioenriched secondary benzyl pivalates is described. This methodology is characterized by an intriguing cooperativity of simple nickel and copper salts to promote the targeted C–B bond formation under mild reaction conditions. Unlike classical SN2-type processes, this protocol occurs with a neat retention of configuration, resulting in synthetically versatile benzyl boronic esters with excellent stereochemical fidelity.

    更新日期:2017-11-10
  • C–S Bond Alkynylation of Diaryl Sulfoxides with Terminal Alkynes by Means of a Palladium–NHC Catalyst
    Synlett (IF 2.151) Pub Date : 2017-11-08
    Yoshida, Yuto, Nogi, Keisuke, Yorimitsu, Hideki

    Sonogashira–Hagihara-type alkynylation of diaryl sulfoxides with unactivated terminal alkynes has been developed. With a combination of a palladium–NHC catalyst and LiOtBu as a base, a series of diaryl sulfoxides were converted into the alkynylated products via C–S bond cleavage.

    更新日期:2017-11-10
  • Acid-Catalyzed Tandem Process for the One-Pot Synthesis of Oxazolidines
    Synlett (IF 2.151) Pub Date : 2017-11-08
    Aldmairi, Abdul Hadi, Knight, David W., Wirth, Thomas

    A simple protocol for the synthesis of oxazolidines from aziridines and allylic alcohols is reported. The solid-supported sulfonic acid catalyst can be easily removed after the reaction by a simple filtration leading to the oxazolidine reaction products in good to excellent yields.

    更新日期:2017-11-10
  • Selective 7-endo-Cyclization of 3-Aza-5-alkenols through Oxidative Pd(II)-Catalyzed Olefin Oxyarylation
    Synlett (IF 2.151) Pub Date : 2017-11-08
    Gazzola, Silvia, Beccalli, Egle M., Borelli, Tea, Castellano, Carlo, Diamante, Daria, Broggini, Gianluigi

    3-Aza-5-alkenols undergo selective 7-endo-trig cyclization when treated with a catalytic Pd(II) species, CuCl2 and ArSnBu3 giving 7-aryl-substituted oxazepanes. The intramolecular alkoxylation occurs with formation of a seven-membered ring only when associated with an arylating step. Otherwise, 6-exo-trig reactions, providing morpholine derivatives, were observed.

    更新日期:2017-11-10
  • Arylation of Amide and Urea C(sp3)–H Bonds with Aryl Tosylates Generated In Situ from Phenols
    Synlett (IF 2.151) Pub Date : 2017-11-03
    Gui, Yong-Yuan, Chen, Xiao-Wang, Zhou, Wen-Jun, Yu, Da-Gang

    The arylation of amide and urea C(sp3)–H bonds with aryl tosylates generated in situ from phenols has been realized at room temperature by combining visible-light-photoredox catalysis, hydrogen-atom-transfer catalysis, and nickel catalysis. This streamlined protocol permits rapid functionalization of phenols and direct transformation of α-amino C(sp3)–H bonds. The C(sp3)–H arylation products are obtained in high yields with good functional-group tolerance at low catalyst loadings.

    更新日期:2017-11-10
  • Copper-Catalyzed Oxidation of Hydrosilanes: A New Method for the Synthesis of Alkyl- and Siloxysilanols
    Synlett (IF 2.151) Pub Date : 2017-11-03
    Arzumanyan, Ashot V., Goncharova, Irina K., Novikov, Roman A., Milenin, Sergey A., Muzafarov, Aziz M.

    A simple method for the preparation of silanols from the corresponding hydrosilanes is reported. The method employs a commercially available oxidizing system based on CuCO3/t-BuOOH(aq) under relatively mild conditions (80 °C, atmospheric pressure) with acetonitrile as the solvent. Furthermore, we present a method that permits the Si−H group to be oxidized to a Si−OH group not only in triethylsilane, but also in bis(trimethylsiloxy)methylsilane, a siloxy derivative of hydrosilane. The products were isolated in gram amounts in yields of 61–73%.

    更新日期:2017-11-10
  • Indium(III) Iodide-Catalyzed Stereoselective Synthesis of β-Glucopyranosides by Using a Glucosyl Fluoride Donor with 2-O-Benzoyl-3,4,6-Tri-O-Benzyl Protection
    Synlett (IF 2.151) Pub Date : 2017-11-03
    Ma, Teng, Li, Changwei, Zhang, Zhan-xin, Wang, Zhaoyan, Yu, Lan, Xue, Weihua

    We have developed a novel protocol for glucosylation by adopting a glucosyl fluoride donor with 2-O-benzoyl-3,4,6-tri-O-benzyl protection. The protocol is useful for the ready assembly of β-linked functional glycoconjugates, and the reaction accommodates a broad range of substrates. Conveniently, water-tolerant and commercially available InI3 is used as a catalyst, and no other additional reagent is required. The method involves an interesting process for glucosyl fluoride activation and, in particular, permits the stereoselective construction of partially benzylated glucopyranosides carrying a selectively removable 2-O-benzoyl group, which hold great potential as glycosyl receptors for building further 1,2-glycosidic linkages.

    更新日期:2017-11-10
  • Pd-Catalyzed One-Pot Borylation/Intramolecular Asymmetric Arylation on α-Ketiminoamides: Innovative Approach to Chiral 3-Amino-2-oxindoles
    Synlett (IF 2.151) Pub Date : 2017-11-03
    Marques, Carolina S., Lawrence, Simon E., Burke, Anthony J.

    3-Amino-2-oxindole derivatives are a common framework found in many natural products and medicinal compounds and thus their synthesis is of significant importance. We report for the first time a one-pot approach for the synthesis of these compounds, using a bory­lation/intramolecular asymmetric arylation sequence starting from ­ortho-bromo-α-ketimino amide derivatives. Pd(OAc)2 was used as the pre-catalyst along with (R)-BINAP as the chiral source. We successfully obtained a family of 3-phenyl-3-(aryl-amino)-indolin-2-one derivatives (11 in total) with excellent yields (up to 98%) and enantioselectivities of up to 76% ee. The reaction is versatile and tolerant of a wide range of functional groups.

    更新日期:2017-11-10
  • Total Synthesis of Eleuthoside A; Application of Rh-Catalyzed Intramolecular Cyclization of Diazonaphthoquinone
    Synlett (IF 2.151) Pub Date : 2017-11-03
    Othman, Dina I. A., Otsuka, Kota, Takahashi, Shuhei, Selim, Khalid B., El-Sayed, Magda A., Tantawy, Atif S., Okauchi, Tatsuo, Kitamura, Mitsuru

    The first total synthesis of (±)-eleutherol and eleuthoside A, the natural cytotoxic substances extracted from medicinal Indonesian plant, is described. First, the synthesis of (±)-eleutherol has been ­accomplished in nine steps starting from bromo methoxy aldehyde with the aid of diazo-transfer chemistry approach. Second, a metal-­catalyzed intramolecular cyclization reaction of the corresponding ­diazonaphthoquinone led to the desired eleuotherol, which served as a precursor to eleuthoside A. Then, several glycosidation routes, using different glucosyl donors, were experimented to reach effective O-glycosidation of eleutherol. The only successful strategy involved Koenigs–Knorr glycosidation using peracetyl glycosyl bromide in the presence of Ag2O and quinoline. This strategy furnished our desired acetylated glycoside of β-configuration, regioselectively. Finally, deacetylation and successive separation of diastereomers were conducted to give eleuthoside A.

    更新日期:2017-11-10
  • A Suzuki-Coupling-Based Generalized Route for the Synthesis of 2-(2/3-Thienyl)cycloalk-1-ene-1-carbaldehydes as Precursors for Condensed Thienophenanthraquinones
    Synlett (IF 2.151) Pub Date : 2017-11-03
    Sarkar, Aparna, Das, Rumpa, Kar, Gandhi K.

    A one-pot, simple, and general method is described for the synthesis of 2-(2/3-thienyl)cycloalk-1-ene-1-carbaldehydes by means of a Pd(0)-catalyzed Suzuki coupling reactions of 2- or 3-thienylboronic acids with 2-bromocycloalk-1-en-1-carbaldehyde derivatives.

    更新日期:2017-11-10
  • Palladium-Catalyzed Synthesis of Aryl Nitriles: Using α-Imino­nitrile as Cyano Source for Aryl Halide Cyanations
    Synlett (IF 2.151) Pub Date : 2017-11-03
    Shi, Yu-Long, Yuan, Qing, Chen, Zhen-Bang, Zhang, Fang-Ling, Liu, Kui, Zhu, Yong-Ming

    An efficient and ligand-free palladium-catalyzed exchange reaction to synthesize aryl nitriles by using α-iminonitrile as a starting reagent has been developed. This methodology provides an optional method for the synthesis of aryl nitriles with moderate to good yields. At the same time, this approach is adaptable for many substrates.

    更新日期:2017-11-10
  • Activation of a Carbon–Carbon Bond in Internal Alkynes: Vinylidene Rearrangement of Disubstituted Alkynes at an Ir Complex
    Synlett (IF 2.151) Pub Date : 2017-10-26
    Kuwabara, Takuya, Takamori, Shuhei, Kishi, Satoshi, Watanabe, Takahiro, Ikeda, Yousuke, Kodama, Shintaro, Minami, Yasunori, Hiyama, Tamejiro, Ishii, Youichi

    Reactions of [Cp*Ir(PPh3)Cl2] with various internal acyl­alkynes in the presence of NaBArF 4 resulted in the selective formation of iridacycles via vinylidene rearrangement. 13C-labeling experiments revealed that the acyl group selectively migrates to the other acetylenic carbon atom. This trend is the same as that in the vinylidene rearrangement of internal alkynes at a group 8 metal center.

    更新日期:2017-11-10
  • Iodide-Catalyzed Carbonylation–Benzylation of Benzyl Chlorides with Potassium Aryltrifluoroborates under Ambient Pressure of Carbon Monoxide
    Synlett (IF 2.151) Pub Date : 2017-10-26
    Han, Wei, Chen, Junjie, Jin, Fengli, Yuan, Xiaorong

    Tetra-N-butylammonium iodide (TBAI) catalyzed carbonylation–benzylation of unactivated benzyl chlorides with potassium aryltrifluoroborates using CO gas has been developed. This reaction is transition-metal free, is carried out under ambient pressure, and provides a wide range of 1,2,3-triarylpropan-1-one derivatives in high yields. The novel method represents a significant improvement over the traditional palladium-catalyzed carbonylation.

    更新日期:2017-11-10
  • Palladium-Catalyzed Copper-Promoted Hiyama-Type Carbon–­Carbon Cross-Coupling Reactions of Dihetaryl Disulfides as ­Electrophiles
    Synlett (IF 2.151) Pub Date : 2017-10-26
    Liu, Ming-Xia, Gong, Hai-Peng, Quan, Zheng-Jun, Wang, Xi-Cun

    Dihetaryl disulfides were used as electrophiles in a palladium-catalyzed carbon–carbon cross-coupling reaction with arylsilanes to ­realize a Hiyama-type reaction. This unique transformation shows high reactivity, excellent functional-group tolerance, and mild reaction conditions, making it an attractive alternative to conventional cross-coupling approaches for carbon−carbon bond construction.

    更新日期:2017-11-10
  • Oxidative Biaryl Coupling of N-Aryl Anilines by Using a Hypervalent Iodine(III) Reagent
    Synlett (IF 2.151) Pub Date : 2017-10-26
    Morimoto, Koji, Koseki, Doichi, Dohi, Toshifumi, Kita, Yasuyuki

    Biaryl diamines are important building blocks in organic ­synthesis. Consequently, it is desirable to develop a general and mild synthetic approach to diverse biaryl diamines. Oxidative coupling is an efficient and promising strategy for the synthesis of these targets. We have now developed a direct formation of biaryl diamines by oxidative coupling using a hypervalent iodine(III) reagent.

    更新日期:2017-11-10
  • Copper(I) Iodide-Catalyzed (Het)arylation of Diethyl Malonate with (Het)aryl Bromides by Using 1,3-Benzoxazole as a Ligand
    Synlett (IF 2.151) Pub Date : 2017-10-26
    Zeng, Yu, Zheng, Hao-liang, Yang, Zhao, Liu, Cheng-Kou, Fang, Zheng, Guo, Kai

    An efficient Ullmann-type coupling of aryl bromides with diethyl malonate in the presence of copper(I) iodide and 1,3-benzoxazole is presented. This method has a broad substrate scope (heterocyclic and phenyl bromides) and good functional-group tolerance (OMe, Me, Ac, CN, NO2, F, and Cl). Moreover, less time is needed to reach full conversion (3–9 hours).

    更新日期:2017-11-10
  • Homoserine and Threonine Peptide Assembly
    Synlett (IF 2.151) Pub Date : 2017-10-24
    Pirrung, Michael C., Bakas, Nicole A.

    Drawing on our recent success with reagent-less peptide-bond formation through serine-based assembly reactions in organic solvent, their range has been expanded to threonine and homoserine (an aspartic acid precursor) in the N-terminal peptide. Amino acid scope available at the assembly C-terminus includes bulky residues not amenable to classical ligation methods, such as cysteine-based NCL in aqueous media. The method was used to assemble a snakebite-toxin-neutralizing peptide from opossums.

    更新日期:2017-11-10
  • Catalytic α-Arylation of Ketones with Heteroaromatic Esters
    Synlett (IF 2.151) Pub Date : 2017-10-23
    Isshiki, Ryota, Takise, Ryosuke, Itami, Kenichiro, Muto, Kei, Yamaguchi, Junichiro

    Heteroaromatic esters were found to be applicable as an arylating agent for the Pd-catalyzed α-arylation of ketones in a decarbonylative fashion. The use of our in-house ligand, dcypt, enabled this unique bond formation. Considering the ubiquity and low cost of ­aromatic esters, the present work will allow for rapid access to valuable α-aryl carbonyl compounds.

    更新日期:2017-11-10
  • Nickel-Catalyzed Decarbonylative Silylation, Borylation, and Amination of Arylamides via a Deamidative Reaction Pathway
    Synlett (IF 2.151) Pub Date : 2017-10-23
    Lee, Shao-Chi, Guo, Lin, Yue, Huifeng, Liao, Hsuan-Hung, Rueping, Magnus

    A nickel-catalyzed decarbonylative silylation, borylation, and amination of amides has been developed. This new methodology allows the direct interconversion of amides to arylsilanes, arylboronates, and arylamines and enables a facile route for carbon–heteroatom bond formations in a straightforward and mild fashion.

    更新日期:2017-11-10
  • Selective N-Monoalkylation of Amide Derivatives with Trialkyl Phosphates
    Synlett (IF 2.151) Pub Date : 2017-10-23
    Asai, Shota, Ban, Kazuho, Monguchi, Yasunari, Sajiki, Hironao, Sawama, Yoshinari

    A highly selective and easily handled monoalkylation of primary amide derivatives by using trialkyl phosphates as alkylating reagents in cyclopentyl methyl ether (CPME) was developed. Various monoalkylated amide derivatives were efficiently synthesized by changing the alkyl moiety (e.g., methyl, ethyl, butyl, or benzyl) of the trialkyl phosphate. These phosphate reagents are relatively stable and easily available, and CPME is a useful solvent in process chemistry.

    更新日期:2017-11-10
  • Synthesis and Photophysical Properties of 3-(Trifluoromethyl)-2H-imidazo[5,1-a]isoquinolinium Chloride Derivatives
    Synlett (IF 2.151) Pub Date : 2017-10-23
    Rahmani, Fariba, Darehkordi, Ali, Ramezani, Mahin, Bazmandegan-Shamili, Alireza

    A series of novel blue-light-emitting 2H-imidazo[5,1-a]isoquinolinium chloride derivatives were synthesized by the reaction of isoquinoline with trifluoroacetimidoyl chlorides and isocyanides in dry CH2Cl2 in excellent yields. Fluorescence studies showed that the compounds absorb UV radiation and then emit blue light at about 481 nm with moderate to good fluorescence quantum yields. These compounds also showed high Stokes shifts, and can be used to develop ­ultrasensitive fluorescent molecular probes to study a variety of biological events and processes.

    更新日期:2017-11-10
  • Construction of Benzylic Stereogenic Carbon Centers through Enantioselective Arylation Reactions
    Synlett (IF 2.151) Pub Date : 2017-10-20
    Liu, Ren-Rong, Liang, Ren-Xiao, Jia, Yi-Xia

    Compounds bearing chiral benzylic stereocenters are important and frequently occur in natural products and drug molecules. In this account, we discuss our recent results on the construction of ­benzylic stereogenic centers based on enantioselective arylation and related domino sequences, mainly including asymmetric Friedel–Crafts alkylation reactions and asymmetric Heck reactions.

    更新日期:2017-11-10
  • Interrupted Pummerer Reaction in Latent/Active Glycosylation
    Synlett (IF 2.151) Pub Date : 2017-10-20
    Meng, Lingkui, Zeng, Jing, Wan, Qian

    A latent/active glycosylation strategy is efficient for rapid ­assembly of oligosaccharides. We recently developed novel OPTB/OPSB and SPTB/SPSB glycosides as two pairs of latent/active glycosyl donors. The active OPSB and SPSB glycosyl donors are efficiently activated by Tf2O via an interrupted Pummerer reaction mechanism. In this account, the design, developments, mechanism studies and applications of these new glycosylation methodologies are described.

    更新日期:2017-11-10
  • Iodine Monoacetate for Efficient Oxyiodinations of Alkenes and Alkynes
    Synlett (IF 2.151) Pub Date : 2017-10-20
    Hokamp, Tobias, Storm, Alena Therese, Yusubov, Mekhman, Wirth, Thomas

    A novel and inexpensive, environmentally friendly method for the preparation of iodine monoacetate is presented using iodine and Oxone in acetic acid/acetic anhydride. The reagent is used in a highly efficient approach for the regio- and diastereoselective iodo­acetoxylation of alkenes and alkynes in a simple one-pot process.

    更新日期:2017-11-10
  • Palladium-Catalyzed Ring-Opening Coupling of Cyclobutenols with Aryl Halides
    Synlett (IF 2.151) Pub Date : 2017-10-20
    Matsuda, Takanori, Matsumoto, Takeshi, Murakami, Akira

    A palladium(0)-catalyzed ring-opening cross-coupling reaction between tert-cyclobutenols and aryl halides produces γ-arylated β,γ-unsaturated ketones. In the case of aryl halides bearing functional groups at the ortho position, the resulting ring-opened ketones undergo intramolecular condensation to afford bicyclic aromatic compounds.

    更新日期:2017-11-10
  • Accounting for Different Reactivities of Sulfinate and Thiosulfate Salts in Regioselective Azetidine Coupling via C–H Sulfenylation of Indoles
    Synlett (IF 2.151) Pub Date : 2017-10-20
    Al-Saedy, Muhannad A. E., Nassoy, Anne-Chloé M. A., Harrity, Joseph P. A.

    The regioselective incorporation of azetidines into heteroaromatic compounds is reported via a formal C–H sulfenylation reaction. While sodium sulfinate salts undergo C3 sulfenylation of electron-rich indoles only, the corresponding thiosulfate salts have proved to be more generally useful. A mechanistic hypothesis for the different reactivities of sulfinate and thiosulfate salts is provided.

    更新日期:2017-11-10
  • Synthesis of Boronocysteine
    Synlett (IF 2.151) Pub Date : 2017-10-20
    Gibson, Samantha M., Macmillan, Derek, Sheppard, Tom D.

    Herein we report the first synthesis of protected boronocysteine. The target compound was prepared via copper-catalysed diastereoselective nucleophilic borylation of a sulfinimine. After deprotection to give the amine as the hydrochloride salt, four boronocysteine amide derivatives were prepared through reaction with a variety of different active acylating agents.

    更新日期:2017-11-10
  • Visible-Light-Induced Chemoselective Synthesis of α-Chloro and Vinyl Sulfones by Sulfonylation of Alkenes
    Synlett (IF 2.151) Pub Date : 2017-10-20
    Niu, Teng-fei, Lin, Dan, Xue, Lin-shuang, Jiang, Ding-yun, Ni, Bang-qing

    Direct sulfonylation between alkenes and sulfonyl chloride was achieved at room temperature by a visible-light-induced photo­redox process. This method allows the chemoselective synthesis of α-chloro and vinyl sulfone derivatives with moderate to high yields. The selectivity of the reaction was fully controlled by the electronic properties of the alkenes.

    更新日期:2017-11-10
  • A Synthesis of Functionalized 2-Indolizin-3-yl-1,3-benzothiazoles from 1-(1,3-Benzothiazol-2-ylmethyl)pyridinium Iodide and ­Acetylenic Esters
    Synlett (IF 2.151) Pub Date : 2017-10-20
    Yavari, Issa, Ghafouri, Kiyana, Naeimabadi, Maryam, Halvagar, Mohammad Reza

    Functionalized 2-indolizin-3-yl-1,3-benzothiazoles were obtained in moderate yields from the reaction between 1-(1,3-benzothiazol-2-ylmethyl)pyridinium iodide and acetylenic esters in acetonitrile. When isoquinoline was used under similar conditions, dialkyl 3-(1,3-benzothiazol-2-yl)pyrrolo[2,1-a]isoquinoline-1,2-dicarboxylates were obtained. The structures of these products have been confirmed by ­X-ray diffractometry.

    更新日期:2017-11-10
  • Sodium Iodide Mediated Oxysulfenylation of Olefins with Thiosulfates: A Strategy for Constructing Sulfenylated 2,3-Dihydrobenzofurans and β-Acetoxy Sulfides
    Synlett (IF 2.151) Pub Date : 2017-10-20
    Zhang, Rongxing, Yan, Zhaohua, Lin, Sen

    A strategy has been developed for constructing sulfenylated 2,3-dihydrobenzofurans and β-acetoxy sulfides through NaI/DMSO-­mediated oxysulfenylation of alkenes with environmentally friendly thiosulfates. The reactions involve simple operations and give a series of sulfenylated 2,3-dihydrobenzofurans or β-acetoxy sulfides in moderate to good yields.

    更新日期:2017-11-10
  • Enantioselective and Diastereoselective Conjugate Radical Additions to α-Arylidene Ketones and Lactones
    Synlett (IF 2.151) Pub Date : 2017-10-20
    Zhao, Changjia, Sibi, Mukund P.

    A highly stereoselective conjugate radical addition to arylidene ketones and lactones has been developed. The conjugate radical additions using chiral salen Lewis acids proceeds with up to 99:1 dr and 87% ee in good to excellent chemical yields.

    更新日期:2017-11-10
  • Rhodium-Catalyzed Desymmetrization of meso-Glutaric Anhydrides to Access Enantioenriched anti,anti-Polypropionates
    Synlett (IF 2.151) Pub Date : 2017-10-17
    Cochran, Brian M., Henderson, Daniel D., Thullen, Scott M., Rovis, Tomislav

    An expedient desymmetrization of 3,5-dimethyl-4-alkoxyglutaric anhydrides to access anti,anti-polypropionates is described. The previously unknown anhydrides are rapidly assembled from readily available precursors. A Rh(I)·t-BuPHOX catalyst system was found to provide good yield and high selectivities. With these conditions, the trisubstituted anhydrides were desymmetrized with various alkyl zinc reagents to provide synthetically useful enantioenriched anti,anti-2,4-dimethyl-3-hydroxy-δ-ketoacids. An identical catalyst system also affords access to syn,syn-stereotriads as well as a partial kinetic resolution of a chiral anhydride.

    更新日期:2017-11-10
  • Extension of the Modified Julia Olefination on Carboxylic Acid Derivatives: Scope and Applications
    Synlett (IF 2.151) Pub Date : 2017-10-16
    Gueyrard, David

    This account relates our work in the field of modified Julia olefination to extend this very useful olefination method to carboxylic acid derivatives. Since our preliminary results on lactones in 2005, the reaction has been extended to a large range of derivatives (lactams, imides and anhydrides) through an intra- or intermolecular process leading to a great variety of structures (enol ethers, enamides and exo enol esters). This article will also focus on the application of this methodology for the preparation of biologically interesting compounds and/or total syntheses of natural products such as C-disaccharide, bistramide A, jaspine B and maculalactone B.

    更新日期:2017-11-10
  • Efficient Method to Synthesize Benzhydrazides by In Situ Oxidation/Coupling of Benzylic Alcohols with Azodicarboxylates
    Synlett (IF 2.151) Pub Date : 2017-10-16
    Azizi, Kobra, Heydari, Akbar

    An efficient synthesis of benzhydrazides has been achieved through the direct acylation of azodicarboxylates with benzylic alcohols in moderate to high yields. The method represents the first practical approach to amides containing a hydrazine structural unit from benzylic alcohols.

    更新日期:2017-11-10
  • Preparation of Aryl(dicyclohexyl)phosphines by C–P Bond-Forming Cross-Coupling in Water Catalyzed by an Amphiphilic-Resin-Supported Palladium Complex
    Synlett (IF 2.151) Pub Date : 2017-10-16
    Hirai, Yoshinori, Uozumi, Yasuhiro

    Aryl(dicyclohexyl)phosphines were prepared by a catalytic C–P bond-forming cross-coupling reaction of haloarenes with dicyclohexylphosphine under heterogeneous conditions in water containing an immobilized palladium complex coordinated to an amphiphilic polystyrene–poly(ethylene glycol) resin supported di(tert-butyl)phosphine ligand.

    更新日期:2017-11-10
  • Study of the Cross-Metathesis Reaction of α-Hydroxy β,γ-Unsaturated Amides towards a Rapid and Flexible Total ­Synthesis of Symbioramide and its Isomer
    Synlett (IF 2.151) Pub Date : 2017-10-12
    Gratais, Alexandre, Bouzbouz, Samir

    The reactivity of novel α-hydroxy β,γ-unsaturated amides in cross-metathesis reactions was extensively studied and used to perform a short total synthesis of symbioramide and its isomer from ­l-serine methyl ester.

    更新日期:2017-11-10
  • Diethylzinc-Mediated Metalloamination–Alkylation of N,N-Dimethylhydrazinoalkenes. Catalysis of C–Zn Alkylation Using Simple Cu(I) Salts
    Synlett (IF 2.151) Pub Date : 2017-10-12
    Mickelsen, Ky, Zabawa, Sean, Livinghouse, Tom

    Metalloamination–alkylation of representative N,N-dimethylhydrazinoalkenes has been shown to be effectively catalyzed by ­CuBr·SMe2, CuCN, and CuI. The current method obviates the use of ­stoichiometric CuCN(LiCl)2 as a promoter for the electrophilic functionalization event.

    更新日期:2017-11-10
  • Thieme Chemistry Journals Awardees – Where Are They Now? Bis(2-pyridyl)amides as Readily Cleavable Amides Under Catalytic, Neutral, and Room-Temperature Conditions
    Synlett (IF 2.151) Pub Date : 2017-10-11
    Adachi, Shinya, Kumagai, Naoya, Shibasaki, Masakatsu

    Mild solvolytic cleavage of bis(2-pyridyl)amide under neutral and room-temperature conditions is described. The inherently stable amide was readily activated by catalytic amounts of metal cations to react with alcohols. Based on X-ray crystallographic analysis, the primary driving force was considered to be amide distortion induced by the metal coordination of two pyridyl groups in a bidentate fashion without affecting the amide functionality. The compatibility of the acid/base-sensitive functionalities and the absence of racemization during solvolysis highlight the mildness of the present protocol.

    更新日期:2017-11-10
  • l-Phenylalanine Triflate as Organocatalyst for Divergent ­Approaches to Trisubstituted Hexahydroimidazo[1,2-a]pyridine and 1,4-Diazepane Derivatives
    Synlett (IF 2.151) Pub Date : 2017-10-11
    Jiang, Jun, Zhang, Miao, Wu, Wen-Biao, Lu, Hai-Bo, Shi, Yu-Long, Li, Jian-Jun

    The convergent synthesis of two biologically significant classes of trisubstituted hexahydroimidazo[1,2-a]pyridine and 1,4-diazepane derivatives from readily available aromatic aldehydes, ketones, and ethane-1,2-diamine is reported. This protocol is promoted by the highly effective l-phenylalanine triflate catalyst through intermolecular annulation, and tolerates a variety of functional groups with excellent yields.

    更新日期:2017-11-10
  • Cyclopropane Intermediates from Insertion Reactions of Platinum–Carbenes: A Route to Heterospiranes
    Synlett (IF 2.151) Pub Date : 2017-10-11
    Kim, Kiseong, Kim, Soyung, Oh, Chang Ho

    Heteroaromatic-anchored enynals with a pendent alkene group were successfully cyclized through a Huisgen-type [3+2] cycloaddition to give a tetracyclic Pt–carbene complex that underwent insertion into the C–H bond in the β-position to give fused cyclopropanes that are otherwise inaccessible. On heating, the cyclopropanes smoothly rearranged to form the corresponding heterospiranes with excellent levels of stereoselectivity and high yields.

    更新日期:2017-11-10
  • Radical Stabilization Algorithm as a Predictive Tool for Novel and Reported Noncanonical Thiele’s Acid Analogues
    Synlett (IF 2.151) Pub Date : 2017-10-06
    Chen, Jun, Lu, Lingxiao, Wulff, Jeremy E.

    We recently showed that a simple radical-stabilization algorithm outperformed traditional frontier-molecular orbital methods for rationalizing the outcome of the venerable Thiele’s acid (or ester) Diels–Alder dimerization. In the present Communication, we describe a novel noncanonical Thiele-type dimerization of a cyclopentadiene phosphine oxide, and show that when steric factors are taken into account the ­radical-stabilization method once again correctly rationalizes the regio­chemical outcome for the reaction. We further show that the method appears to be general for all known Thiele- and half-Thiele dimerization events.

    更新日期:2017-11-10
  • Asymmetric Alkene and Arene Halofunctionalization Reactions in Meroterpenoid Biosynthesis
    Synlett (IF 2.151) Pub Date : 2017-09-27
    Moore, Bradley S.

    Meroterpenoid natural products are important bioactive molecules with broad distribution throughout nature. In Streptomyces bacteria, naphthoquinone-based meroterpenoids comprise a simple yet structurally fascinating group of natural product antibiotics that are enzymatically constructed through a series of asymmetric alkene and arene halofunctionalization reactions. This account article highlights our discovery and characterization of a group of vanadium-dependent chloroperoxidase enzymes that catalyze halogen-assisted cyclization and rearrangement reactions and have inspired biomimetic syntheses of numerous meroterpenoid natural products.

    更新日期:2017-11-10
  • Radical Allylation: E-Selective Radical Conjugate Addition–Elimination Reaction from Morita–Baylis–Hillman Adducts
    Synlett (IF 2.151) Pub Date : 2017-09-27
    Lebargy, Cyril, De Schutter, Coralie, Legay, Remi, Pfund, Emmanuel, Lequeux, Thierry

    Triethylborane-mediated radical allylation was performed from Morita–Baylis–Hillman alcohols with no need of protecting group. The radical conjugated addition–elimination reaction is highly selective, and trisubstituted E-alkenes were obtained. This reaction opened a new route for the preparation of functionalized α,β-unsaturated ketones.

    更新日期:2017-11-10
  • Elemental Sulfur-Mediated Decarboxylative Redox Cyclization ­Reaction: Copper-Catalyzed Synthesis of 2-Substituted Benzo­thiazoles
    Synlett (IF 2.151) Pub Date : 2017-09-27
    Wang, Xin, Li, Xiaotong, Hu, Renhe, Yang, Zhao, Gu, Ren, Ding, Sai, Li, Pengyi, Han, Shiqing

    A S8-mediated directed decarboxylative redox-cyclization strategy for the synthesis of 2-substituted benzothiazoles from o-iodoanilines, arylacetic acids, and elemental sulfur catalyzed by cheap copper metal has been developed. This reaction is operationally simple, ligand-free, compatible with a wide range of functional groups, and provides the desired products in good to excellent yields. In addition, a gram-scale experiment was carried out to furnish PMX 610, an antitumor drug.

    更新日期:2017-11-10
  • Palladium-Catalyzed Decarboxylation of Benzyl Fluorobenzoates
    Synlett (IF 2.151) Pub Date : 2017-09-26
    Makida, Yusuke, Matsumoto, Yasutaka, Kuwano, Ryoichi

    The decarboxylation of benzyl fluorobenzoates has been developed by using the palladium catalyst prepared in situ from Pd(η3-allyl)Cp and bulky monophosphine ligand XPhos. The catalytic reaction afforded a range of fluorinated diarylmethanes in good yields with broad functional-group compatibility. The substrates were readily synthesized by condensation of the corresponding benzoic acid with benzyl alcohol. Therefore, the transformation is formally regarded as a cross-coupling reaction between fluorine-containing benzoic acids and benzyl alcohols.

    更新日期:2017-11-10
  • Synthesis of Tetraarylmethanes by the Triflic Acid-Promoted Formal Cross-Dehydrogenative Coupling of Triarylmethanes with Arenes
    Synlett (IF 2.151) Pub Date : 2017-09-26
    Nambo, Masakazu, Yim, Jacky C.-H., Fowler, Kevin G., Crudden, Cathleen M.

    The formal cross-dehydrogenative coupling of triarylmethanes with arenes promoted by triflic acid and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone is described. This method provides a variety of tetraarylmethane derivatives in good to excellent yields from triarylmethanes that can be readily prepared by our previous methods. Control experiments suggest a possible catalytic cycle involving the generation of a trityl cation intermediate followed by nucleophilic addition of the arene.

    更新日期:2017-11-10
  • Metal-Free Mild Synthesis of Novel 1′H-Spiro[Cycloalkyl-1,2′-quinazolin]-4′(3′H)-ones by an Organocatalytic Cascade Reaction
    Synlett (IF 2.151) Pub Date : 2017-09-26
    Ramesh, Rathinam, Kalisamy, Periyathambi, Malecki, Jan Grzegorz, Lalitha, Appaswami

    A concise organocatalytic method for the facile synthesis of some novel 1′H-spiro[cycloalkyl-1,2′-quinazolin]-4′(3′H)-ones via a one-pot, three-component condensation of isatoic anhydride, aryl or aliphatic amines and a cyclic ketone is described.

    更新日期:2017-11-10
  • Synthesis of 6-Thiocyanatophenanthridines by Visible-Light- and Air-Promoted Radical Thiocyanation of 2-Isocyanobiphenyls
    Synlett (IF 2.151) Pub Date : 2017-09-26
    Singh, Manjula, Yadav, Arvind K., Yadav, Lal Dhar S., Singh, R. K. P.

    A convenient, efficient, and metal-free synthesis of 6-thiocyanatophenanthridines by visible-light- and air-mediated, eosin Y-catalyzed, sequential radical cyclization and aromatization of 2-isocyanobiphenyls with ammonium thiocyanate is reported. Advantageously, the protocol utilizes inexpensive, clean, and sustainable natural resources such as visible light and atmospheric oxygen at room temperature in a one-pot procedure.

    更新日期:2017-11-10
  • N1-Arylation of 1,4-Benzodiazepine-2-ones with Diaryliodonium Salts
    Synlett (IF 2.151) Pub Date : 2017-09-25
    Khan, Raysa, Felix, Robert, Kemmitt, Paul D., Coles, Simon J., Tizzard, Graham J., Spencer, John

    A library of N1-arylated 5-phenyl-1,3-dihydro-2H-1,4-benzodiazepin-2-ones has been synthesized starting with unsymmetrical diaryliodonium salts using aqueous ammonia as a base. This can also be applied to a similar 1,3,4-benzotriazepin-2-one derivative.

    更新日期:2017-11-10
  • Synthesis of Dansyl-Substituted Cryptands Containing Triaza­cycloalkane Moieties and their Evaluation as Fluorescent Chemosensors
    Synlett (IF 2.151) Pub Date : 2017-09-21
    Chernichenko, Nataliya M., Shevchuk, Vadim N., Averin, Alexei D., Maloshitskaya, Olga A., Beletskaya, Irina P.

    A method for the synthesis of a new family of cryptands containing 1,4,7-triazacyclononane and 1,5,9-triazacyclododecane moieties and dansyl fluorophore groups has been elaborated starting from free triazacycloalkanes and employing Pd(0)-catalyzed amination at the macrocyclization step. The dependence of the products yields on the nature of reagents has been established. The majority of synthesized macrobicycles have been evaluated as possible chemosensors for detecting metal cations. Compound comprising 1,4,7-triazacyclononane and dioxadiamine linker proved to be a prospective colorimetric sensor for Cu(II) by changing its absorption spectrum in the presence of this cation, while other cryptands demonstrated full quenching of fluorescence in the presence of Cu(II) and Al(III) what makes them promising fluorescent molecular probes for these metals.

    更新日期:2017-11-10
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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