- Alkynyl triazenes enable divergent syntheses of 2-pyrones
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The 2-pyrone motif occurs frequently in bioactive natural products and is appreciated as synthetic intermediates. However, only few methods allow for diversifying functional group modifications on this relevant heterocycle. The distinct properties of 1-alkynyl triazenes promote a smooth addition of propiolic acids across the triple bond. Addition of catalytic amounts of silver salt induces cyclization to 2-pyrones. Depending on the reaction temperature, either 6-triazenyl or 5-triazenyl 2-pyrones are selectively formed. The triazenyl unit is subsequently replaced by a variety of valuable groups in a one-pot process yielding for instance 2-fluoro pyrones. The substitution occurs with an intriguing 1,5-carbonyl transposition. Moreover, the triazenyl group serves as traceless activating group for subsequent Diels-Alder cycloadditions and as a constituting unit for rare fused aminopyrazole pyrone heterocycles.
- Tan, Jin-Fay,Bormann, Carl Thomas,Severin, Kay,Cramer, Nicolai
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p. 9140 - 9145
(2021/07/12)
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- Rhodium-Catalyzed [2+2+2] Cycloaddition Reactions of Linear Allene–Ene–Ynes to afford Fused Tricyclic Scaffolds: Insights into the Mechanism
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Allene-(E)-ene-yne N-tosyl-tethered substrates 3 a–3 h were efficiently prepared and their rhodium-catalyzed [2+2+2] cycloaddition reactions were evaluated. The cycloadditions are chemoselective as only the proximal double bond of the allene reacted to af
- Cassú, Daniel,Parella, Teodor,Solà, Miquel,Pla-Quintana, Anna,Roglans, Anna
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supporting information
p. 14889 - 14899
(2017/10/27)
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- Ligand-Controlled Cobalt-Catalyzed Transfer Hydrogenation of Alkynes: Stereodivergent Synthesis of Z- and E-Alkenes
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Herein, we report a novel cobalt-catalyzed stereodivergent transfer hydrogenation of alkynes to Z- and E-alkenes. Effective selectivity control is achieved based on a rational catalyst design. Moreover, this mild system allows for the transfer hydrogenation of alkynes bearing a wide range of functional groups in good yields using catalyst loadings as low as 0.2 mol %. The general applicability of this procedure is highlighted by the synthesis of more than 50 alkenes with good chemo- and stereoselectivity. A preliminary mechanistic study revealed that E-alkene product was generated via sequential alkyne hydrogenation to give Z-alkene intermediate, followed by a Z to E alkene isomerization process.
- Fu, Shaomin,Chen, Nan-Yu,Liu, Xufang,Shao, Zhihui,Luo, Shu-Ping,Liu, Qiang
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supporting information
p. 8588 - 8594
(2016/07/27)
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- Chiral pyrrolidines and piperidines from enantioselective rhodium-catalyzed cascade arylative cyclization
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A new rhodium-catalyzed asymmetric arylative cyclization of nitrogen-tethered alkyne-enoate with arylboronic acids is described. In this process two new carbon-carbon bonds and one stereocenter are formed, providing access to pyrrolidines and piperidines
- Serpier, Fabien,Flamme, Benjamin,Brayer, Jean-Louis,Folléas, Beno?t,Darses, Sylvain
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supporting information
p. 1720 - 1723
(2015/04/14)
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- Secondary phosphine oxide-gold(I) complexes and their first application in catalysis
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A series of new secondary phosphine oxide (SPO)-gold(I) complexes have been synthesized and characterized by X-ray crystallography. Complexes exhibited dimeric structures interconnected by O-H···Cl hydrogen bonds. Their first use in homogeneous catalysis
- Schroeder, Felix,Tugny, Coralie,Salanouve, Elise,Clavier, Herve,Giordano, Laurent,Moraleda, Delphine,Gimbert, Yves,Mouries-Mansuy, Virginie,Goddard, Jean-Philippe,Fensterbank, Louis
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supporting information
p. 4051 - 4056
(2014/10/15)
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- Enantioselective IrI-catalyzed carbocyclization of 1,6-enynes by the chiral counterion strategy
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Enantioenriched bicyclo[4.1.0]hept-2-enes were synthesized by Ir I-catalyzed carbocyclization of 1,6-enynes. No chiral ligands were used, CO and PPh3 were the only ligands bound to iridium. Instead, the stereochemical information was
- Barbazanges, Marion,Auge, Mylene,Moussa, Jamal,Amouri, Hani,Aubert, Corinne,Desmarets, Christophe,Fensterbank, Louis,Gandon, Vincent,Malacria, Max,Ollivier, Cyril
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experimental part
p. 13789 - 13794
(2012/01/06)
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- (Pentamethylcyclopentadienyl)iridium dichloride dimer {[IrCp*Cl 2]2}: A novel efficient catalyst for the cycloisomerizations of homopropargylic diols and N-tethered enynes
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(Pentamethylcyclopentadienyl)iridium dichloride dimer {[IrCp*Cl 2]2}-catalyzed hydroalkoxylation of bis-homopropargylic alcohols provides an efficient access to dioxabicyclo[2.2.1]ketals. The cycloisomerizations proceed under mild conditions, with low catalytic loadings and short reaction times. This new protocol involving an Ir(III) catalyst also promoted the cycloisomerization of nitrogen-tethered 1,6-enynes to give azabicyclo[4.1.0]heptenes, enhancing the synthetic potential of our method. Copyright
- Benedetti, Erica,Simonneau, Antoine,Hours, Alexandra,Amouri, Hani,Penoni, Andrea,Palmisano, Giovanni,Malacria, Max,Goddard, Jean-Philippe,Fensterbank, Louis
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supporting information; experimental part
p. 1908 - 1912
(2011/10/05)
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- Rhodium-catalysed alkoxycarbonylative cyclisation reactions of 1,6-enynes
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The rhodium-catalysed carbonylation of 1,6-enynes possessing an electron-deficient alkenyl moiety in an alcohol reagent in the presence of a rhodium complex proceeded stereo- and chemoselectively to afford exocyclic α,β-enoates.
- Ziyanak, Firat,Kus, Melih,Artok, Levent
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supporting information; experimental part
p. 897 - 902
(2011/06/22)
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- Rhodium-catalyzed synthesis of γ-butyrolactams and pyrrolidines via cycloisomerization of N-tethered 1,6-enynes
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A rhodium-catalyzed cycloisomerization reaction of N-tethered 1,6-enynes with an intramolecular halogen shift has been developed, providing a useful process for the synthesis of stereo defined γ-butyrolactam and pyrrolidine derivatives in good to excellent yields. Effects of both electronic feature and steric structure of the substrates on the outcome of the reaction were investigated.
- Wang, Jianping,Xie, Xiaomin,Ma, Fangfang,Peng, Zhiyong,Zhang, Lei,Zhang, Zhaoguo
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experimental part
p. 4212 - 4217
(2010/07/05)
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- Stereocontrolled preparation of bicyclic alkaloid analogues: an approach towards the kinabalurine skeleton
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An approach towards the construction of bicyclic analogues of monoterpene alkaloids belonging to the kinabalurine, incarvilline and skytanthine families of natural products is reported. These syntheses rely on a stereoselective intramolecular Pauson-Khand
- Kavanagh, Yvonne,O'Brien, Matthew,Evans, Paul
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experimental part
p. 8259 - 8268
(2009/12/24)
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- Rhodium N-heterocyclic carbene-catalyzed [4 + 2] and [5 + 2] cycloaddition reactions
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A rhodium complex of N-heterocyclic carbene (NHC) has been developed for intra- and intermolecular [4 + 2] and intramolecular [5 + 2] cycloaddition reactions. This is the first use of a transition-metal NHC complex in a Diels-Alder-type reaction. For the
- Lee, Sang Ick,Park, Se Yeoun,Park, Ji Hoon,Jung, Il Gu,Choi, Soo Young,Chung, Young Keun,Lee, Bun Yeoul
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- Cycloisomerization of 1,6-enynes using acetate as a nucleophile under palladium (II) catalysis
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(Chemical Equation Presented) An efficient method for the synthesis of five-membered carbo- and heterocyclic compounds, including fused rings, was reported using acetate as a nucleophile in the cyclization of 1,6-enynes under palladium(II) catalysis. The
- Zhang, Qinghai,Xu, Wei,Lu, Xiyan
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p. 1505 - 1507
(2007/10/03)
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- Silicon-initiated carbonylative carbotricyclization and [2+2+2+1] cycloaddition of enediynes catalyzed by rhodium complexes
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The reaction of dodec-11-ene-1,6-diynes or their heteroatom congeners with a hydrosilane catalyzed by Rh(acac)(CO)2 at ambient temperature and pressure of CO gives the corresponding fused 5-7-5 tricyclic products, 5-oxo-1,3a,4,5,7,9-hexahydro-3
- Bennacer, Bibia,Fujiwara, Masaki,Lee, Seung-Yub,Ojima, Iwao
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p. 17756 - 17767
(2007/10/03)
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- Nickel-catalyzed addition of dimethylzinc to aldehydes across alkynes and 1,3-butadiene: An efficient four-component connection reaction
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In the presence of 10 mol % of Ni(acac)2, four components comprising Me2Zn, alkynes, 1,3-butadiene, and carbonyl compounds combine in this order in 1:1:1:1 ratio to furnish (3E,6Z)-octadien-1-ols 1 in good yields. Similarly, the coupling reaction of Me2Zn, 1,ω-dienynes 5, and carbonyls furnishes 1-alkylidene-2-(4′-hydroxy- (1′E)-alkenyl)cyclopentanes and -cyclohexanes 6 and their oxygen and nitrogen heterocycle derivatives in good yield and an excellent level of 1,5-diastereoselectivity with respect to the cycloalkane methine carbon and the OH-bearing carbon of the C2 side chain. The reaction is completed in most cases within 1 h at room temperature under nitrogen, tolerates an ester, a hydroxy, an allyl and propargyl ethers, an allylamino, and a pyridyl functionalities, and accommodates a variety of aromatic and aliphatic alkynes and carbonyls (aldehydes and ketones).
- Kimura, Masanari,Ezoe, Akihiro,Mori, Masahiko,Tamaru, Yoshinao
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p. 201 - 209
(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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- Ruthenium-catalyzed alkyne-propargyl alcohol addition. An asymmetric total synthesis of (+)-alpha-kainic acid.
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A novel route to the neuroexcitatory amino acid, kainic acid, is developed. The key concept derives from a ruthenium-catalyzed cycloisomerization of a tethered alkyne-propargyl alcohol to form a cyclic 2-vinyl-1-acyl compound. A single stereocenter introd
- Trost, Barry M,Rudd, Michael T
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p. 1467 - 1470
(2007/10/03)
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- Synthesis of aromatic triynes as precursors to helicene derivatives
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A general and versatile synthetic approach to a broad series of aromatic triynes as precursors to helicene derivatives has been developed. Employing a set of simple tools, triynes comprising the (phenylethynyl)benzene, 1-(phenylethynyl)naphthalene, and 1-(1-naphthylethynyl)-naphthalene moiety have been prepared in good to excellent yields throughout the whole reaction sequence. The methodology allows constructing various types of a junction between the central diarylacetylene moiety and the attached acetylene units to get the target triynes of general formula R-C≡C-CH2-X-CH2-Ar-C≡C-Ar-CH 2-X-CH2-C≡C-R or R-C≡C-CH2CH2-Ar-C=C-Ar-CH2CH 2-C≡C-R (R = H, CH3, TMS, or TIPS; X = O, NTs, or C(CO2CH3)2; Ar/Ar = 2-phenylene or 2-naphthylene).
- Stara, Irena G.,Kollarovic, Adrian,Teply, Filip,Stary, Ivo,Saman, David,Fiedler, Pavel
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p. 577 - 609
(2007/10/03)
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- Rhodium(I)‐catalyzed allenic pauson–khand reaction
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Procedures yielding N‐(but‐2‐yn‐1‐yl)‐4‐methylbenzenesulfonamide (1) as a white solid; N‐(but‐2‐yn‐1‐yl)‐N‐(3‐(((tert‐butyldiphenylsilyl)oxy)methyl)penta‐3,4‐dien‐1‐yl)‐4‐methylbenzenesulfonamide (3) as a pale yellow oil; and 5‐(((tert‐butyldiphenylsilyl)
- Burchick, Joseph E.,Wells, Sarah M.,Brummond, Kay M.
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