- Radical Approach to Thioester-Containing Polymers
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A new approach to radical ring-opening polymerization is presented that employs a new thionolactone monomer to generate polymers with thioester-containing backbones. The use of a thiocarbonyl acceptor overcomes longstanding reactivity problems in the field to give complete ring-opening and quantitative incorporation into a variety of acrylate polymers. The resulting copolymers readily degrade under hydrolytic conditions, in addition to cysteine-mediated degradation through transthioesterification. The strategy is compatible with reversible addition-fragmentation chain transfer (RAFT) polymerization and permits the synthesis of block polymers for the preparation of well-defined macromolecular structures.
- Smith, Ronald A.,Fu, Guanyao,McAteer, Owen,Xu, Mizhi,Gutekunst, Will R.
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Read Online
- Regioselective biocatalytic self-sufficient Tishchenko-type reactionviaformal intramolecular hydride transfer
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A self-sufficient nicotinamide-dependent intramolecular bio-Tishchenko-type reaction was developed. The reaction is catalyzed by alcohol dehydrogenases and proceeds through formal intramolecular hydride transfer on dialdehydes to deliver lactones. Regioselectivity on [1,1′-biphenyl]-2,2′-dicarbaldehyde substrates could be controlledviathe electronic properties of the substituents. Preparative scale synthesis provided access to substituted dibenzo[c,e]oxepin-5(7H)-ones.
- Buljubasic, Isa,Hall, Mélanie,Laggner, Olivia,Merusic, Kemal,Reiter, Tamara,Tassano, Erika,Vogel, Andreas
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supporting information
p. 6340 - 6343
(2020/06/21)
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- (Cyclopentadienone)iron-Catalyzed Transfer Dehydrogenation of Symmetrical and Unsymmetrical Diols to Lactones
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Air-stable iron carbonyl compounds bearing cyclopentadienone ligands with varying substitution were explored as catalysts in dehydrogenative diol lactonization reactions using acetone as both the solvent and hydrogen acceptor. Two catalysts with trimethylsilyl groups in the 2- A nd 5-positions, [2,5-(SiMe3)2-3,4-(CH2)4(δ4-C4C= O)]Fe(CO)3 (1) and [2,5-(SiMe3)2-3,4-(CH2)3(δ4-C4C= O)]Fe(CO)3 (2), were found to be the most active, with 2 being the most selective in the lactonization of diols containing both primary and secondary alcohols. Lactones containing five-, six-, and seven-membered rings were successfully synthesized, and no over-oxidations to carboxylic acids were detected. The lactonization of unsymmetrical diols containing two primary alcohols occurred with catalyst 1, but selectivity was low based on alcohol electronics and modest based on alcohol sterics. Evidence for a transfer dehydrogenation mechanism was found, and insight into the origin of selectivity in the lactonization of 1°/2° diols was obtained. Additionally, spectroscopic evidence for a trimethylamine-ligated iron species formed in solution during the reaction was discovered.
- Tang, Yidan,Meador, Rowan I. L.,Malinchak, Casina T.,Harrison, Emily E.,McCaskey, Kimberly A.,Hempel, Melanie C.,Funk, Timothy W.
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p. 1823 - 1834
(2020/02/04)
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- Degradable vinyl copolymers through thiocarbonyl addition-ring-opening (TARO) polymerization
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The radical copolymerization of the thionolactone dibenzo[c,e]oxepane-5-thione with acrylates, acrylonitrile, and N,N-dimethylacrylamide afforded copolymers containing a controllable amount of backbone thioesters which could be selectively cleaved. The pr
- Bingham, Nathaniel M.,Roth, Peter J.
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supporting information
p. 55 - 58
(2019/01/03)
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- Platinum-on-Carbon-Catalyzed Aqueous Oxidative Lactonization of Diols by Using Molecular Oxygen
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A lactonization of various diols catalyzed by platinum on carbon (Pt/C) in water under an atmosphere of molecular oxygen was developed. Derivatives of 1,4- 1,5- and 1,6-diols were transformed into the corresponding five-, six-, and seven-membered lactones by the present oxidative lactonization method.
- Ban, Kazuho,Sajiki, Hironao,Sawama, Yoshinari,Takakura, Ryoya
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p. 1919 - 1923
(2019/09/30)
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- Ruthenium(II) Catalysis/Noncovalent Interaction Synergy for Cross-Dehydrogenative Coupling of Arene Carboxylic Acids
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A ruthenium-catalyzed cross-dehydrogenative coupling is developed with the aid of a weakly coordinating carboxylic acid group toward the dimerization of arene carboxylic acids. The protocol is operationally simple and suitable to fabricate diverse homodimerized as well as cross-dimerized products in high yields. Computational insights have also been unveiled to comprehend the plausible reaction mechanism. The critical innovation of the synthetic strategy hinges on the soluble basic additive DBU, which constitutes a synergy of Ru(II)-catalysis with noncovalent interaction and, thus, stabilizes pivotal intermediates to promote the challenging dimerization process.
- Dana, Suman,Chowdhury, Deepan,Mandal, Anup,Chipem, Francis A. S.,Baidya, Mahiuddin
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p. 10173 - 10179
(2018/11/21)
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- A microwave for rapid preparation of biaryl seven-membered lactone method
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The invention provides a method for quickly preparing polyaryls 7-membered lactone in a microwave manner. The method comprises the following steps of A, performing umpolung reaction under microwave irradiation of 700-900 W and at the temperature of 25-80 DEG C by using a compound 1 as a reagent, using dissolved oxygen acetonitrile as solvent and using N-heterocyclic carbene as a catalyst to obtain a crude product; and B, extracting the polyaryls 7-membered lactone, namely a compound 2, from the crude product. An equation of the reaction is as shown in the specification, wherein R and R' are respectively and independently selected from halogen, nitro group, methyl group, methoxy group and phenyl group of which a benzene ring has two common carbon atoms, and X is halogen. By the method, the polyaryls 7-membered lactone with yield higher than 85% can be obtained within 60 minutes at most. Compared with a reported preparation technology, the method has the advantages that reaction time is shortened, production efficiency is high, and a technology is simple.
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Paragraph 0029-0031
(2017/08/10)
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- A microwave-promoted/Assisted method for rapid preparation of biaryl seven-membered lactones
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Background: Biaryl seven-membered lactones (BSLs), the target compounds are a class of bioactive compounds with anti-Arrhythmic activity, which also serve as a starting material or structural units for chemical synthesis. Objective: To report a simple and efficient procedure for the synthesis of biaryl seven-membered lactones. Method: Under microwave, the umpolung reaction was promoted by N-heterocyclic carbenes under oxygen, with anhydrous potassium carbonate as base and with 1,4,7,10,13,16-Hexanoxacyclooctadecane (18-crown-6) as a phase-Transfer catalyst. Results: The practical protocol was found to be compatible with different structurally diverse substrates and with moderate to excellent yields. Conclusion: This synthesis method has the advantage of high efficacy and novelty, short reaction time, operation simplicity, mild condition and high yields, providing a useful and atom-economic approach to the synthesis of BSLs.
- Hu, Chunqi,Li, Jun,Du, Wenting
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p. 301 - 305
(2017/06/05)
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- Synthesis of biaryls via intramolecular free radical ipso-substitution reactions
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A variety of functionalised biaryls and heterobiaryls are prepared by intramolecular free radical [1,5]-ipso-substitution using sulfonamide and sulfonate derived tethering chains. The overall efficiency of the process is determined by appropriately positioned substituents on the aromatic acceptor ring. The extension of the process to benzylic sulfonates and their corresponding N-methylsulfonamide alternatives as substrates in potential [1,6]-ipso-substitution reactions leads mainly to the alternative [1,7] addition products.
- Ujjainwalla, Feroze,Da Mata, Maria Lucília E.N.,Pennell, Andrew M.K.,Escolano, Carmen,Motherwell, William B.,Vázquez, Santiago
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p. 6701 - 6719
(2015/08/24)
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- Organocatalytic Aerobic Oxidation of Benzylic sp3 C-H Bonds of Ethers and Alkylarenes Promoted by a Recyclable TEMPO Catalyst
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An entirely metal-free catalyst system consisting of an easily prepared recyclable new TEMPO derived sulfonic salt catalyst, and mineral acids (NaNO2 and HCl) has been developed for selective aerobic oxidation of structurally diverse benzylic sp3 C-H bonds of ethers and alkylarenes. The mild reaction conditions allow for the generation of synthetically and biologically valued isochromanones and xanthones from readily accessible alkyl aromatic precursors in good yields.
- Zhang, Zhiguang,Gao, Yuan,Liu, Yuan,Li, Jianjun,Xie, Hexin,Li, Hao,Wang, Wei
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supporting information
p. 5492 - 5495
(2015/11/18)
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- Synthesis of dibenzo[c,e]oxepin-5(7H)-ones from benzyl thioethers and carboxylic acids: Rhodium-catalyzed double C-H activation controlled by different directing groups
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A rhodium(III)-catalyzed cross-coupling of benzyl thioethers and aryl carboxylic acids through the two directing groups is reported. Useful structures with diverse substituents were efficiently synthesized in one step with the cleavage of four bonds (C-H, C-S, O-H) and the formation of two bonds (C-C, C-O). The formed structure is the privileged core in natural products and bioactive molecules. This work highlights the power of using two different directing groups to enhance the selectivity of a double C-H activation, the first of such examples in cross-oxidative coupling.
- Zhang, Xi-Sha,Zhang, Yun-Fei,Li, Zhao-Wei,Luo, Fei-Xian,Shi, Zhang-Jie
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supporting information
p. 5478 - 5482
(2015/04/27)
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- Efficient and Selective Cu/Nitroxyl-Catalyzed Methods for Aerobic Oxidative Lactonization of Diols
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Cu/nitroxyl catalysts have been identified that promote highly efficient and selective aerobic oxidative lactonization of diols under mild reaction conditions using ambient air as the oxidant. The chemo- and regioselectivity of the reaction may be tuned by changing the identity of the nitroxyl cocatalyst. A Cu/ABNO catalyst system (ABNO = 9-azabicyclo[3.3.1]nonan-N-oxyl) shows excellent reactivity with symmetrical diols and hindered unsymmetrical diols, whereas a Cu/TEMPO catalyst system (TEMPO = 2,2,6,6-tetramethyl-1-piperidinyl-N-oxyl) displays excellent chemo- and regioselectivity for the oxidation of less hindered unsymmetrical diols. These catalyst systems are compatible with all classes of alcohols (benzylic, allylic, aliphatic), mediate efficient lactonization of 1,4-, 1,5-, and some 1,6-diols, and tolerate diverse functional groups, including alkenes, heterocycles, and other heteroatom-containing groups.
- Xie, Xiaomin,Stahl, Shannon S.
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supporting information
p. 3767 - 3770
(2015/04/14)
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- Iron(II) pincer-catalyzed synthesis of lactones and lactams through a versatile dehydrogenative domino sequence
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The synthesis of lactones and lactams by using iron(II) pincer-catalyzed dehydrogenative methodology was developed. Starting from 1,n-diols or 1,n-amino alcohols, this domino transformation takes place through initial dehydrogenation of the substrates, subsequent intramolecular cyclization, and final oxidation to afford the desired products in good yields. The ability to access heterocycles of different sizes makes this protocol especially versatile, in which two consecutive oxidation reactions are performed without requiring an external oxidant. In this paper, we report the application of the Fe-MACHO-BH complex [carbonylhydrido(tetrahydroborato)[bis(2-diisopropylphosphinoethyl)amino]iron(II)] in this atom-efficient and environmentally benign process, for which molecular hydrogen is formed as the only stoichiometric side product. Just a little pinch: The iron(II) pincer-catalyzed synthesis of lactones and lactams from easily available 1,n-diols and 1,n-amino alcohols is explored. The use of a nontoxic metal as well as the generation of molecular hydrogen as the only stoichiometric byproduct makes this method a highly atom-efficient and environmentally benign process.
- Pea-Lpez, Miguel,Neumann, Helfried,Beller, Matthias
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p. 865 - 871
(2015/03/14)
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- Acceptorless dehydrogenative lactonization of diols by Pt-loaded SnO2 catalysts
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We report herein a new heterogeneous catalytic system for dehydrogenative lactonization of various diols under solvent-free and acceptor-free conditions using 1 mol% of Pt-loaded SnO2, providing the first successful example of acceptorless lactonization of 1,6-hexanediol to ε-caprolactone by a heterogeneous catalyst. This journal is
- Touchy, Abeda Sultana,Shimizu, Ken-Ichi
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p. 29072 - 29075
(2015/04/14)
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- Facile organocatalytic domino oxidation of diols to lactones by in situ-generated TetMe-IBX
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The domino oxidation of diols to lactones is an important transformation, and catalytic protocols that allow this conversion smoothly are scarce. Capitalizing on the established reactivity of tetramethyl-IBX (TetMe-IBX) and its in situ generation in the presence of a co-oxidant, such as oxone, we have shown that a variety of diols can be converted to the corresponding lactones in respectable yields by employing the precursor of TetMe-IBX, namely, tetramethyl-o-iodobenzoic acid (TetMe-IA), as a catalyst in 5 mol % in the presence of 2 equiv of oxone.
- Jhulki, Samik,Seth, Saona,Mondal, Manas,Moorthy, Jarugu Narasimha
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p. 2286 - 2293
(2014/03/21)
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- Dehydrogenative lactonization of diols in aqueous media catalyzed by a water-soluble iridium complex bearing a functional bipyridine ligand
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A new catalytic system for the dehydrogenative lactonization of a variety of benzylic and aliphatic diols in aqueous media was developed. By using a water-soluble, dicationic iridium catalyst bearing 6,6′-dihydroxy-2, 2′-bipyridine as a functional ligand, highly atom economical and environmentally benign synthesis of various lactones was achieved in good to excellent yields. Recovery and reuse of the catalyst were also accomplished by a simple phase separation and the recovered catalyst maintained its high activity at least until the fifth run. Copyright
- Fujita, Ken-Ichi,Ito, Wataru,Yamaguchi, Ryohei
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p. 109 - 112
(2014/01/23)
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- Catalytic and chemoselective oxidation of activated alcohols and direct conversion of diols to lactones with in situ-generated bis-IBX catalyst
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The twisted 3,3′-diiodo-2,2′,6,6′-tetramethoxybiphenyl-4, 4′-dicarboxylic acid (DIDA) was designed and synthesized for the in situ generation of Bis-IBX and catalytic oxidations. The seemingly better solubility of the in situ-generated Bis-IBX and the attenuated reactivity arising from its unique structural features and methoxy substituents allowed the catalytic oxidation of activated alcohols selectively using DIDA/oxone. Chemoselective oxidations were demonstrated for substrates containing two different hydroxy groups. Furthermore, the unique reactivity of DIDA was demonstrated for sequential oxidation reactions of 1,4- and 1,6-diols to give lactones catalytically in respectable yields.
- Seth, Saona,Jhulki, Samik,Moorthy, Jarugu Narasimha
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p. 2445 - 2452
(2013/05/22)
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- A general and efficient zinc-catalyzed oxidation of benzyl alcohols to aldehydes and esters
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Go green: A general and efficient zinc-catalyzed oxidation of benzyl alcohols has been developed. In the presence of a zinc catalyst, various aldehydes and esters have been prepared in good to excellent yields under mild conditions (see scheme).
- Wu, Xiao-Feng
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experimental part
p. 8912 - 8915
(2012/09/22)
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- Highly efficient synthesis of medium-sized lactones via oxidative lactonization: Concise total synthesis of isolaurepanf
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A catalytic amount of TEMPO in the presence of PhI(OAc)2 effected oxidative lactonization of 1,6- and 1,7-diols, directly affording seven- and eight-membered lactones, respectively, in good yields. The Royal Society of Chemistry 2010.
- Ebine, Makoto,Suga, Yuto,Fuwa, Haruhiko,Sasaki, Makoto
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supporting information; experimental part
p. 39 - 42
(2010/04/26)
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- Hydroruthenation triggered catalytic conversion of dialdehydes and keto aldehydes to lactones
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Lactonization of dialdehydes and keto aldehydes was effectively catalyzed by RuHCl(CO)(PPh3)3. A cascade lactonization sequence accompanied by cross-coupling with enones was also attained.
- Omura, Sohei,Fukuyama, Takahide,Murakami, Yuji,Okamoto, Hiromi,Ryu, Ilhyong
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supporting information; experimental part
p. 6741 - 6743
(2010/03/25)
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- An efficient oxidative lactonization of 1,4-diols catalyzed by Cp*Ru(PN) complexes
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An efficient oxidative lactonization of 1,4-diols in acetone is accomplished by the well-defined ruthenium catalyst, whose bifunctional nature underlies the high efficiency as well as unique chemo- and regioselectivity of the reaction which provides a rapid access to γ-butyrolactones including flavor lactones hinokinin, and muricatacin.
- Ito, Masato,Osaku, Akihide,Shiibashi, Akira,Ikariya, Takao
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p. 1821 - 1824
(2008/02/02)
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- The OsO4-mediated oxidative cleavage of olefins catalyzed by alternative osmium sources
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The OsO4-mediated oxidative cleavage of olefins is compatible with alternative, easier-to-handle osmium sources. Four different osmium sources were employed with favorable results.
- Whitehead, Daniel C.,Travis, Benjamin R.,Borhan, Babak
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p. 3797 - 3800
(2007/10/03)
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- Productive chloroarene C-Cl bond activation: Palladium/phosphine-catalyzed methods for oxidation of alcohols and hydrodechlorination of chloroarenes
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The palladium/phosphine-catalyzed productive chloroarene C-Cl bond activation provides general, efficient, and functional group friendly methods for the selective oxidation of alcohols and the hydrodechlorination of chloroarenes.
- Bei, Xiaohong,Hagemeyer, Alfred,Volpe, Anthony,Saxton, Robert,Turner, Howard,Guram, Anil S.
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p. 8626 - 8633
(2007/10/03)
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- Direct lactonization of alkenols via osmium tetroxide-mediated oxidative cleavage
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(Matrix presented) A highly efficient, mild, and simple protocol is presented for the tandem OsO4-mediated oxidative cleavage/oxidative lactonization of alkenols to lactones. The protocol couples the OsO 4-catalyzed oxidative cleavage of olefins with Oxone as the co-oxidant with the direct oxidation of aldehydes in alcoholic solvents to their corresponding esters.
- Schomaker, Jennifer M.,Travis, Benjamin R.,Borhan, Babak
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p. 3089 - 3092
(2007/10/03)
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- Productive utilization of chlorobenzene: Palladium-catalyzed selective oxidation of alcohols
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(Matrix presented) The palladium/ligand-catalyzed activation of chlorobenzene provides a general, efficient, and functional group friendly method for the selective oxidation of alcohols to carbonyl compounds.
- Guram, Anil S.,Bei, Xiaohong,Turner, Howard W.
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p. 2485 - 2487
(2007/10/03)
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- Selective oxidation of alcohols to aldehydes or ketones
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Alcohols are oxidized to their corresponding ketone or aldehyde using an aryl chloride oxidant and a metal-ligand complex or metal/ligand composition. This reaction is particularly applicable to aromatic alcohols and cyclic and bicyclic aliphatic alcohols.
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- Observations on the nature of the tethering chain in the synthesis of biaryls and heterobiaryls via intramolecular free radical ipso substitution reactions
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A study of benzylic sulfonates and their corresponding N-methylsulphonamide derivatives as substrates in potential free radical [1,6] ipso substitution reactions reveals a preference for the alternative [1,7] addition mode. Empirical guidelines for biaryl
- Da Mata, Maria Lucilia E.N.,Motherwell, William B.,Ujjainwalla, Feroze
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p. 141 - 144
(2007/10/03)
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- TETRAZOLE FORMATION DURING BAMFORD-STEVENS REACTION OF DIPHENALDEHYDE BIS-TOSYLHYDRAZONE
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The Bamford-Stevens reaction of diphenaldehyde bis-tosylhydrazone (4), examined in five different procedures, afforded phenanthrene as main reaction product. 5H-6-Azadibenzotetrazolocycloheptene (6) was obtained as by-product (32percent) in aprotic basic reaction conditions.The reaction mechanisms are discussed.Formation of a tetrazole during Bamford-Stevens reaction of a bis-tosylhydrazone seems to be observed for the first time.
- Banciu, Mircea D.,Banciu, Anca,Draghici, Constantin,Petride, Aurica,Chiraleu, Filip
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p. 1165 - 1174
(2007/10/03)
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- Novel Reduction of Carboxylic Acids, Esters, Amides and Nitriles Using Samarium Diiodide in the Presence of Water
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Aromatic carboxylic acids, esters, amides, nitriles, chlorides, ketones and nitro compounds were rapidly reduced by the samarium diiodide-H2O system to the corresponding products at room temperature in good yields.
- Kamochi, Yasuko,Kudo, Tadahiro
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p. 1495 - 1498
(2007/10/02)
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- Heterocycles with an Azaallyl System, 4. - 5H-Dibenzazepines with Donor Groups at the 7-Position
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5H-Dibenzazepines substituted with a methoxy (1) or methylthio group (10) at the 7-position have been synthesized from 6,7-dihydro-5H-dibenzazepin-5-one (5) by regioselective O- or S-alkylation with methyl trifluoromethansulfonate and subsequent NH-deprotonation.According to the spectroscopic properties the semicyclic 7-membered alkyl imidates exist exclusively in the benzenoid 5H structure. Key Words: 5H-Dibenzazepines / Imidates, alkyl, heterocyclic
- Roehrkasten, Ralf,Kreher, Richard P.
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p. 2085 - 2090
(2007/10/02)
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- Intramolecular Catalysis. Part 4. The Intramolecular Cannizzaro Reaction of Biphenyl-2,2'-dicarbaldehyde, Biphenyl-2,2'-dicarbaldehyde and 4,4'-or 5,5'-or 6,6'-Disubstituted Biphenyl-2,2'-dicarbaldehydes
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Biphenyl-2,2'-dicarbaldehyde, along with its α,α'- isomer, and a series of 4,4'-, 5,5'- and 6,6'- disubstituted biphenyl-2,2'-dicarbaldehydes have been shown to undergo Cannizzaro reactions in 30percent (v/v) dioxane-water containing base.The reaction has been shown to be intramolecular and of third order; first order in substrate and second order in base.The rate coefficients have been measured at several temperatures and activation parameters evaluated.Studies of solvent isotope, solvent and salt effects have been made.The kinetic isotope effect, KH/kD, was found to be ca. 1.8.The effect of 4,4'- and 5,5'-disubstitution was assessed by use of the Hammett equation to give ρ at 30 deg C to be ca. 4.6.Severe steric effects were noted for 6,6'-dimethyl substitution.The alkaline hydrolysis of corresponding ε-lactones of 2'-hydroxymethylbiphenyl-2-carboxylic acids was studied under the same conditions.The intermediacy of the lactones in the intramolecular Cannizzaro reaction can be excluded.The evidence for the Cannizzaro reaction indicates a mechanistic pathway involving rate-determining hydride transfer from the dianion of a hydrated formyl group to the second formyl group.An estimate is made of effective concentration of the intramolecular hydride transfer.
- Abbaszadeh, Mohammad R.,Bowden, Keith
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p. 2081 - 2087
(2007/10/02)
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- A MACROCYCLE CONTAINING TWO BIPHENYL AND TWO ALANINE SUBUNITS, SYNTHESIS AND CONFORMATION IN SOLUTION
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The synthesis and solution conformation of the macrocycle cyclo(-2-Ala)2 3 is presented.The compound 3 contains two alanine and two molecules of the novel pseudoamino acid 2-aminomethyl-2'-carboxymethylbiphenyl 2 in the ring.A phthalimido-protected derivative of 2 is obtained in three steps from diphenic anhydride.The compound 2 is coupled to H-AlaOCH3 and the resulting "dipeptide" dimerizes at the conditions of an azide coupling to 3 (20percent).The macrocycle 3 exists in three diastereomeric forms 3A, 3B and 3C which can be separated by HPLC.The form with R,S configuration of the biphenyl groups has C1 symmetry (3C).The one- and two-dimenzional 1H-NMR data of 3C support a structure where the biphenyl groups are orientated in an orthogonal arrangement.One alanine is in an equatorial C7 conformation, the other alanine is part of a stretched peptide chain.The forms 3A and 3B with C2 symmetry exist probably as equilibrating structures in solution.The NMR data can be explained with β-sheet conformations as well as with more bent structures containing γ-loops.
- Brandmeier, Volker,Feigel, Martin
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p. 1365 - 1376
(2007/10/02)
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- Reactions of Trialkylborane. VI. Reduction of Carbonyl Compounds with Trialkylborane
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The reduction of anhydrides, lactones, esters, carboxylic acids and acyl chlorides with trialkylborane is described.Cyclic anhydrides were reduced with 4 mol eq of trialkylborane at temperatures above 300 deg C to give diol derivatives via the lactones.Lactones, esters, carboxylic acids and acyl chlorides were reduced under similar conditions to give the corresponding alcohol derivatives.Keywords-reduction; trialkylborane; anhydride; lactone; ester; carboxylic acid; alcohol; carbonyl compound
- Nose, Atsuko,Kudo, Tadahiro
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p. 4335 - 4339
(2007/10/02)
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- 5-SUBSTITUTED AND 5,7-DISUBSTITUTED 5,7-DIHYDRODIBENZOTHIEPINS AND THE CORRESPONDING S-OXYGENATED COMPOUNDS: ALKYLAMINES, CARBOXYLIC ACIDS, AND CARBOXAMIDES; SYNTHESIS AND PHARMACOLOGICAL SCREENING
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Reaction of 5,7-dihydrodibenzothiepin with n-butyllithium resulted in the partial sulfur extrusion and in the formation of the 9,10-dihydrophenanthrene-9-thiolate anion (B).Its further transformations (by hydrolysis, aminoalkylation and spontaneous dehydrogenation) led to phenanthrene-9-thiol (IX), the corresponding disulfide X, and the S-(2-dimethylaminoethyl) derivatives XI and XIV.Reactions of 5-chloro-5,7-dihydrodibenzothiepin (II) with the corresponding Grignard reagents were only a poor source of the amines III and IV.Reaction of the sulfoxide XVIII with n-butyllithium or with sodium hydride and the following treatment with 2-dimethylaminoethyl chloride gave the amine XIX in a low yield.Only the sulfone X was found more useful for preparing the 5- and 5,7-substituted derivatives.Treatment with n-butyllithium and following carbonation afforded mixtures of the monocarboxylic acid XXI and dicarboxylic acid XXVIII.Via acid chlorides they were transformed to the methylamides XXII and XXIX and to the dimethylamides XXIII and XXX.The amide XXIII was reduced to the 5-(dimethylaminomethyl) compound XXV.Lithiation of the sulfone XX or treatment with sodium hydride and the following action of 2-dimethylaminoethyl chloride and 3-dimethylaminopropyl chloride gave the amines XXVI, XXVII, and XXXI.Only the phenanthrene derivatives XI and XIV, and the amino sulfone XXVII showed clear indications of thymoleptic activity as potential antidepressants.
- Sindelar, Karel,Holubek, Jiri,Ryska, Miroslav,Koruna, Ivan,Protiva, Miroslav
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p. 2848 - 2868
(2007/10/02)
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- OXIDATION OF ALCOHOLS BY TRANSITION METAL COMPLEXES-IV THE RHODIUM CATALYSED SYNTHESIS OF ESTERS FROM ALDEHYDES AND ALCOHOLS
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Both RhH(CO)PPh3)3 and a catalyst made in situ from RhCl3.3H2O, PPh3 and Na2CO3 catalyse the reaction of a range of aldehydes with simple primary alcohols to give esters together with alcohols formed by reduction of the aldehydes.The proportion of ester can be increased by adding an efficient hydrogen acceptor.The reaction can also be used to produce 5- and 7-membered lactones from aromatic dialdehydes.Propan-2-ol and the in situ catalyst reduce some aromatic aldehydes to the corresponding alcohols without concomitant ester formation.
- Grigg, Ronald,Mitchell, Thomas R. B.,Sutthivaiyakit, Somyote
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p. 4313 - 4319
(2007/10/02)
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- PREPARATION OF OPTICALLY ACTIVE BRIDGED BIPHENYLS VIA A STEREOSELECTIVE SYNTHESIS OF THEIR MONO (TRICARBONYLCHROMIUM) COMPLEXES. CHIROPTICAL PROPERTIES AND ABSOLUTE CHIRALITIES OF THE COMPLEXES AND LIGANDS
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Reaction of the mono(tricarbonylchromium) complex 3 of diphenic acid anhydride with chiral amines gave the optically active imides 9-11. 10 and 11, from (S)-(-) and (R)(+)-phenylalaninol, respectively were separated by chromatography into exo- and endo-di
- Eyer, M.,Schloegl, K.,Schoelm, R.
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p. 4239 - 4244
(2007/10/02)
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- Stereochemistry of Metallocenes, 44. Syntheses and Configurations of Tricarbonylchromium Complexes of Diphenic Acid and Its Derivatives (Biphenyl Tricarbonylchromium Complexes, 3)
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Mono and bis tricarbonylchromium complexes of diphenic acid and its monomethylester (3, 4, 15, 16) were prepared by treating the corresponding methyl and trimethylsilylesters (e.g. 12) with Cr(CO)6 and subsequent hydrolysis of the complexes 1, 2, 13, and 14.Diborane reduction of the carboxylic acids gave hydroxymethyl derivatives, amongst which the diol 8a is a key substance for configurational analyses by 1H-nmr and ir spectroscopy.In this context monosubstituted biphenyl complexes (9-11) were prepared as reference substances.Complexation of the lactone 23 of 2'-hydroxymethyl biphenyl-2-carboxylic acid afforded (besides two isomeric monocomplexes) mainly the trans-biscomplex 26b, a key intermediate for ring opening and cyclization reactions.The stereochemical possibilities of the biscomplexes are discussed.The "racemate" configuration is preliminarily assigned to diphenic acid bistricarbonylchromium and its derivatives. - Keywords: Benchrotrenes; Hydrogen bridges, intramolecular; Lactone of 2'-hydroxymethyl-biphenyl-2-carboxylic acid, mono and bis tricarbonylchromium
- Schloegl, Karl,Schoelm, Richard
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p. 259 - 274
(2007/10/02)
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