- Antimicrobial Hydantoin-grafted Poly(ε-caprolactone) by Ring-opening Polymerization and Click Chemistry
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Novel degradable and antibacterial polycaprolactone-based polymers are reported in this work. The polyesters with pendent propargyl groups are successfully prepared by ring-opening polymerization and subsequently used to graft antibacterial hydantoin moieties via click chemistry by a copper(I)-catalyzed azide-alkyne cycloaddition reaction. The well-controlled chemical structures of the grafted copolymers and its precursors are verified by FT-IR spectroscopy, NMR spectroscopy, and GPC characterizations. According to the DSC and XRD results, the polymorphisms of these grafted copolymers are mostly changed from semicrystalline to amorphous depending on the amount of grafted hydantoin. Antibacterial assays are carried out with Bacillus subtilis and two strains of Escherichia coli and show fast antibacterial action.
- Tan, Licheng,Maji, Samarendra,Mattheis, Claudia,Chen, Yiwang,Agarwal, Seema
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- Formation and characterization of inclusion complexes of alkyne functionalized poly(ε-caprolactone) with β-cyclodextrin. Pseudo-polyrotaxane-based supramolecular organogels
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β-Cyclodextrin has been found to form pseudo-polyrotaxanes with propargyl functionalized poly(ε-caprolactone) in N,N-dimethylformamide. The formation of inclusion complexes was proven by 1H NMR and FT-IR spectroscopy, SEC, dynamic light scatter
- Jazkewitsch, Olga,Ritter, Helmut
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- Cyclodextrin-modified polyesters from lactones and from bacteria: An approach to new drug carrier systems
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Copper(I)-catalyzed cycloaddition of synthetic and bacterial copolyesters bearing pendant alkyne group with mono-(6-azido-6-desoxy)-β-cyclodextrin was carried out to synthesize β-CD-functionalized copolyester. The synthetic clickable copolyesters were obtained by the ring-opening copolymerization of the propargyl-modified lactones and ε-caprolactone. The bacterial copolyesters containing an alkyne group were biosynthesized from a mixture of 10-undecynoic acid and hexanoic acid by the Gram-negative bacteria Pseudomonas oleovorans. The modified products of the click reaction were characterized by FT-IR, 1H NMR spectroscopy, and DSC. Furthermore, the host guest capability of covalently attached β-cyclodextrin moieties was proved by dynamic light scattering measurements.
- Jazkewitsch, Olga,Mondrzyk, Adam,Staffel, Rebecca,Ritter, Helmut
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- Regioselective Crossed Aldol Reactions under Mild Conditions via Synergistic Gold-Iron Catalysis
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A synergistic gold-iron (Au-Fe) catalytic system was developed for sequential alkyne hydration and vinyl Au addition to aldehydes or ketones. Fe(acac)3 was identified as an essential co-catalyst in preventing vinyl Au protodeauration and facilitating nucleophilic additions. Effective C–C bond formation was achieved under mild conditions (room temperature) with excellent regioselectivity and high efficiency (1% [Au], up to 95% yields). The intramolecular reaction was also achieved, giving successful macrocyclization (16–31 ring sizes) with excellent yields (up to 90%, gram scale) without extended dilution (0.2 M), which highlights the great potential of this new crossed aldol strategy in challenging target molecule synthesis. Effective construction of the C–C bond is one of the most important tasks in organic synthesis. Whereas aldol condensation is a classic C–C bond-forming transformation, it requires other chemical promoters, such as strong base and reactive acidic catalysts. As a result, the overall transformation is limited in terms of ideal atom economy and environmentally friendly operation. With the discovery of a gold-iron (Au-Fe) synergistic catalysis system, here we describe a new approach to facilitating alkyne hydration and sequential vinyl Au addition to carbonyls. This approach gives the C–C bond-forming products in excellent yields, wide substrate scope, and great functional-group compatibility under mild conditions. This protocol can also be applied to macrocyclization without extended dilution. This C–C bond-forming strategy could facilitate challenging molecule synthesis in chemical, biological, and medicinal research. We report a synergistic gold-iron (Au-Fe) catalytic system to access vinyl Au reactivity by avoiding frequently occurring protodeauration. Fe(acac)3 was identified as an essential co-catalyst, facilitating vinyl Au addition to aldehydes. A broad substrate scope was obtained under mild conditions (room temperature) with excellent regioselectivity and high efficiency (1% [Au], up to 95% yields). This protocol offers a practical solution for achieving macrocyclization (16–31 ring sizes, up to 90%, gram scale) without extended dilution, highlighting the synthetic utility in complex molecular synthesis.
- Chen, Hao,Jean, Jonathan,Shan, Chuan,Shi, Xiaodong,Teng, Shun,Wang, Jin,Wojtas, Lukasz,Ye, Xiaohan,Yi, Yaping,Yuan, Teng,Zhao, Pengyi
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supporting information
p. 1420 - 1431
(2020/06/19)
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- Self-assembled coordination thioether silver(I) macrocyclic complexes for homogeneous catalysis
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The bis-ortho-thioether 9,10-bis[(o-methylthio)phenyl]anthracene was synthesized as a syn-atropisomer, as revealed by X-ray diffraction. This alkylaryl thioether ligand (L) formed different macrocyclic complexes by coordination with silver(I) salts depending on the nature of the anion: M2L2 for AgOTf and AgOTFA, M6L4 for AgNO3. A discrete M2L complex was obtained in the presence of bulky PPh3AgOTf. These silver(I) complexes adopted similar structures in solution and in the solid state. As each sulfur atom in the ligand is prochiral, macrocycles L2M2 were obtained as mixtures of diastereoisomers, depending on the configurations of the sulfur atoms coordinated to silver cations. The X-ray structures of the two L2·(AgOTf)2 stereoisomers highlighted their different geometry. The catalytic activity of all silver(I) complexes was effective under homogeneous conditions in two tandem addition/cycloisomerization of alkynes using 0.5-1 mol % of catalytic loading.
- Cao, Zhen,Lacoudre, Aline,Rossy, Cybille,Bibal, Brigitte
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supporting information
p. 2465 - 2472
(2019/11/11)
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- Bismuth(iii)-catalyzed cycloisomerization and (hetero)arylation of alkynols: Simple access to 2-(hetero)aryl tetrahydrofurans and tetrahydropyrans
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2-(Hetero)aryl tetrahydrofurans and tetrahydropyrans were successfully synthesized using Bi(OTf)3-catalyzed hydroalkoxylation (cycloisomerization) of alkynols (via 5 or 6 exo-dig cyclization) and intermolecular (hetero)arylation. This reaction involves a highly efficient cascade process, where initially the alkynol undergoes a cycloisomerization step via activation of the triple bond and generates the oxocarbenium ion, which subsequently participates in the (hetero)hydroarylation step with electron-rich arenes. Simple to complex suitably functionalized alkynols (4-pentyn-1-ols and 5-hexyn-1-ols) and electron-rich aromatic compounds were found to be reliable substrates in this cascade transformation and furnished a wide range of oxygen heterocycles. This practical tandem process provides a means to build libraries related to pharmacologically active molecules and natural product like scaffolds.
- Nakate, Ashwini K.,Pratapure, Madhukar S.,Kontham, Ravindar
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supporting information
p. 3229 - 3240
(2018/05/15)
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- Chemoenzymatic route to optically active dihydroxy cyclopenta[b]naphthalenones; precursors for decalin-based bioactive natural products
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The development of an efficient chemoenzymatic route for the synthesis of optically active dihydroxy cyclopenta[b]naphthalenones; (+)-1,4a-dihydroxy-4a,5,6,7,8,8a,9,9a-octahydro-1H-cyclopenta[b]naphthalen-2(4H)-one (+)-10 and (+)-1,8a-dihydroxy-4a,5,6,7,8,8a,9,9a-octahydro-1H-cyclopenta[b]naphthalen-2(4H)-one (+)-11 is described. Different lipases and esterases were tested in the enzymatic hydrolysis of the corresponding acetates (±)-4a-hydroxy-2-oxo-2,4,4a,5,6,7,8,8a,9,9a-decahydro-1H-cyclopenta[b]naphthalen-1-yl acetate (±)-8, (±)-8a-hydroxy-2-oxo-2,4,4a,5,6,7,8,8a,9,9a-decahydro-1H-cyclopenta[b]naphthalen-1-yl acetate (±)-9, CRL (Candida Rugosa Lipase) and PLE (Pig Liver Esterase) were found to be the most effectual enzymes; for (?)-8 by 47% ee with the corresponding dihydroxy; (+)-10 by 98% ee in the presence of CRL; whereas, (?)-8 was obtained with 40% ee with the corresponding dihydroxy, (+)-10 with 58% ee in the PLE hydrolysis. It was concluded that CRL was the best biocatalyst for the substrate (±)-8. Moreover, enzymatic resolution in the presence of CRL yields, (?)-9 with 46% ee with the corresponding dihydroxy derivative; (+)-11 with 98% ee; however, in the presence of PLE, yields (?)-9 with 36% ee as well as the related dihydroxy derivative; (+)-11 with 49% ee respectively. The study concluded that CRL is the best biocatalyst for compounds (±)-8 and (±)-9.
- ?zdemirhan, Devrim,Sar??elik, ?zlem
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p. 118 - 124
(2017/01/12)
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- Synergistic Catalysis: Metal/Proton-Catalyzed Cyclization of Alkynones Toward Bicyclo[3.n.1]alkanones
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A highly efficient and practical synergistically metal/proton-catalyzed Conia-ene reaction for the synthesis of bicyclo[3.n.1]alkanones has been developed. This synergistic catalysis was successfully utilized in modifying natural compounds such as methyl dihydrojasmonate, α,β-thujone, and 5α-cholestan-3-one. Furthermore, the bridged carbonyl group of bicyclo[3.2.1]alkanones could be easily attacked by nucleophiles to give the ring-opened cycloheptenone products or bicyclo[4.2.1]amide in excellent yields. These reactions provide rapid access to a diverse range of cyclic structures from simple starting materials or naturally occurring compounds. A highly efficient and practical synergistically metal/proton-catalyzed Conia-ene reaction for the synthesis of bicyclo[3.n.1]alkanones has been developed. The reaction was successfully utilized in modifying natural compounds such as methyl dihydrojasmonate, α,β-thujone, and 5α-cholestan-3-one. Furthermore, the bicyclo[3.2.1]alkanones can be ring-opened by nucleophiles to give the corresponding products in excellent yields.
- Zhu, Shifa,Zhang, Qiaohui,Chen, Kai,Jiang, Huanfeng
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supporting information
p. 9414 - 9418
(2015/08/06)
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- Silver-free activation of ligated gold(I) chlorides: The use of [Me3NB12Cl11]- as a weakly coordinating anion in homogeneous gold catalysis
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Phosphane and N-heterocyclic carbene ligated gold(I) chlorides can be effectively activated by Na[Me3NB12Cl11] (1) under silver-free conditions. This activation method with a weakly coordinating closo-dodecaborate anion was shown to be suitable for a large variety of reactions known to be catalyzed by homogeneous gold species, ranging from carbocyclizations to heterocyclizations. Additionally, the capability of 1 in a previously unknown conversion of 5-silyloxy-1,6-allenynes was demonstrated.
- Wegener, Michael,Huber, Florian,Bolli, Christoph,Jenne, Carsten,Kirsch, Stefan F.
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supporting information
p. 1328 - 1336
(2015/02/05)
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- Gold-catalyzed 1,3-acyloxy migration/5-exo-dig cyclization/1,5-acyl migration of diynyl esters
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Working three shifts: Polyconjugated δ-diketones are formed stereoselectively in high yields by the gold-catalyzed rearrangement of 1,6-diyn-3-yl esters. This cascade involves a 1,3-sigmatropic acyloxy shift, a 5-exo-dig cyclization of the resulting allenyne, and an unprecedented 1,5-sigmatropic shift of an acyl fragment. The usefulness of the products was shown by an efficient acid-catalyzed transformation into a complex polycyclic framework. Copyright
- Lebuf, David,Simonneau, Antoine,Aubert, Corinne,Malacria, Max,Gandon, Vincent,Fensterbank, Louis
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p. 6868 - 6871
(2011/08/06)
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- Convenient synthesis of non-conjugated alkynyl ketones from keto aldehydes by a chemoselective one-pot nonaflation - Base catalyzed elimination sequence
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Keto aldehydes were selectively converted to non-conjugated alkynyl ketones possessing an unsubstituted alkyne terminus using one-pot nonaflation - base catalyzed elimination reaction sequences. Consecutive one-pot nonaflation of keto aldehydes with perfluorobutane-1-sulfonyl fluoride and elimination of the nonaflyl group using the P1 phosphazene base resulted in the formation of a terminal CC triple bond with the keto group remaining intact. Careful optimization of the reaction conditions enabled a highly chemoselective conversion of the aldehyde function in the presence of unprotected keto groups exploiting a minor difference in acidity of their α-hydrogen atoms. Scope and limitations of the protocol as well as possible implementation of these substrates in Sonogashira coupling were explored.
- Boltukhina, Ekaterina V.,Sheshenev, Andrey E.,Lyapkalo, Ilya M.
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p. 5382 - 5388
(2011/08/06)
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- Efficient control for the cationic platinum(II)-catalyzed concise synthesis of two types of fused carbocycles with angular oxygen functionality
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Double trouble: An efficient method for the preparation of two types of synthetically useful bicyclo[5.4.0]undecanes with an angular oxygen functionality was realized starting from easily available substrates; this method was based on the [3+2] cycloaddit
- Kusama, Hiroyuki,Watanabe, Eiichi,Ishida, Kento,Iwasawa, Nobuharu
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supporting information; experimental part
p. 2273 - 2277
(2012/06/30)
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- Pyrrole synthesis catalyzed by AgOTf or cationic Au(I) complexes
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Either silver trifluoromethanesulfonate or a mixture of gold(I) chloride, silver trifluoromethanesulfonate, and triphenylphosphine catalyze the formation of pyrroles from substituted β-alkynyl ketones and amines. The reactions proceed by using 5 mol % of catalyst with yields of isolated pyrroles ranging from 13% to 92%. Sixteen examples are used to compare the effectiveness of each catalyst.
- Harrison, Tyler J.,Kozak, Jennifer A.,Corbella-Pane, Montserrat,Dake, Gregory R.
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p. 4525 - 4529
(2007/10/03)
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- A gold-catalyzed domino process to the steroid framework
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The facile formation of the B and C ring of rac-desoxyequilenin and of a chrysenone derivative in just one preparative step is demonstrated, applying a gold-catalyzed domino process, which involves a benzopyrylium cation as the key intermediate and an int
- Hildebrandt, Dirk,Dyker, Gerald
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p. 6728 - 6733
(2007/10/03)
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- Ruthenium-catalyzed cycloisomerizations of diynols
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A wide variety of diynols containing tertiary, secondary, and primary propargylic alcohols undergo a cycloisomerization reaction to form dienones and dienals in the presence of a catalytic amount of [CpRu(CH3CN) 3]PF6. The
- Trost, Barry M.,Rudd, Michael T.
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p. 4763 - 4776
(2007/10/03)
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- Base promoted reactions of 4-pentynones
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Different substituted furans are synthesized by cyclization of 4-pentynones using potassium tert-butoxide in DMF. A different reaction pattern is observed when the same componds were treated with sodium methoxide in MeOH. A new approach to 2-propargyl-car
- Arcadi, Antonio,Marinelli, Fabio,Pini, Elena,Rossi, Elisabetta
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p. 3387 - 3390
(2007/10/03)
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- An Effective and Selective Conjugate Propargylation Reaction of Stannylallenes to α,β-Unsaturated Carbonyl Compounds and α-Nitro Olefins
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Stannylallenes (1) reacted with α,β-unsaturated carbonyl compounds and α-nitro olefins in the presence of TiCl4 to give the corresponding conjugate propargylation products.Thus, the reaction of 1 with cyclic and acyclic α,β-unsaturated carbonyl compounds (2) gave β-propargylic ketones (3) in high yields.With α-nitro olefins (4), two types of products, β-propargylic nitroalkanes (5) and α-propargylic ketones (6), were obtained selectively depending on the presence or absence of the α-substituent of 4.Transformation of the products (6) to cyclopentenone derivatives (10 and 12) are also described.
- Haruta, Jun-ichi,Nishi, Koichi,Matsuda, Satoshi,Akai, Shuji,Tamura, Yasumitsu,Kita, Yasuyuki
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p. 4853 - 4859
(2007/10/02)
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