- Enantioselective Reductive Cyanation and Phosphonylation of Secondary Amides by Iridium and Chiral Thiourea Sequential Catalysis
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The combination of transition-metal catalysis and organocatalysis increasingly offers chemists opportunities to realize diverse unprecedented chemical transformations. By combining iridium with chiral thiourea catalysis, direct enantioselective reductive cyanation and phosphonylation of secondary amides have been accomplished for the first time for the synthesis of enantioenriched chiral α-aminonitriles and α-aminophosphonates. The protocol is highly efficient and enantioselective, providing a novel route to the synthesis of optically active α-functionalized amines from the simple, readily available feedstocks. In addition, the reactions are scalable and the thiourea catalyst can be recycled and reused.
- Chen, Dong-Huang,Sun, Wei-Ting,Zhu, Cheng-Jie,Lu, Guang-Sheng,Wu, Dong-Ping,Wang, Ai-E,Huang, Pei-Qiang
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supporting information
p. 8827 - 8831
(2021/03/16)
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- Direct chemoselective allylation of inert amide carbonyls
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Direct allylation of inert amide carbonyls utilizing the Schwartz reagent afforded either substituted tertiary or secondary amines. A preactivation step was successfully avoided, which is generally a requisite to increase the electrophilicity of amides. The reaction exhibited remarkable functional group tolerance and proceeded even in the presence of methyl esters and nitro groups.
- Oda, Yukiko,Sato, Takaaki,Chida, Noritaka
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p. 950 - 953
(2012/04/18)
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- Iridium-catalyzed reduction of secondary amides to secondary amines and imines by diethylsilane
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Catalytic reduction of secondary amides to imines and secondary amines has been achieved using readily available iridium catalysts such as [Ir(COE) 2Cl]2 with diethylsilane as reductant. The stepwise reduction to secondary amine proceeds through an imine intermediate that can be isolated when only 2 equiv of silane is used. This system requires low catalyst loading and shows high efficiency (up to 1000 turnovers at room temperature with 99% conversion have been attained) and an appreciable level of functional group tolerance.
- Cheng, Chen,Brookhart, Maurice
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supporting information; experimental part
p. 11304 - 11307
(2012/09/05)
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- Sequential Cu(I)/Pd(0)-catalyzed multicomponent coupling and annulation Protocol for the synthesis of indenoisoquinolines
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Copper-catalyzed coupling of imines, vinylstannanes, or alkynes and o-bromoaroyl chlorides followed by Pd(0)-catalyzed annulations afforded indenoisoquinolines. Protocols requiring minimal purifications were developed, providing new methods for the construction of combinatorial libraries.
- Jayanth, Thiruvellore Thatai,Zhang, Lei,Johnson, Thomas S.,Malinakova, Helena C.
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supporting information; experimental part
p. 815 - 818
(2009/07/18)
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- CHEMOKINE RECEPTOR MODULATORS
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The invention provides compounds of Formula (I) and pharmaceutical compositions comprising compounds of Formula (I). These compounds are useful treating or preventing HIV infections, and in treating proliferative disorders such as inhibiting the metastasis of various cancers.
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Page/Page column 545
(2008/12/07)
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- The simple and selective synthesis of 3-amino-2,2-difluorocarboxylic esters and difluoro-β-lactams using ethyl bromodifluoroacetate in the presence of rhodium catalyst
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Treatment of imines (5) with ethyl bromodifluoroacetate (1) and Et 2Zn in the presence of RhCl(PPh3)3 in anhydrous medium gave difluoro-β-lactams (7) in good to excellent yields, while 3-amino-2,2-difluorocarboxylic esters (6) were obtained in good yields by adding MgSO4·7H2O to the reaction medium.
- Sato, Kazuyuki,Tarui, Atsushi,Matsuda, Seiji,Omote, Masaaki,Ando, Akira,Kumadaki, Itsumaro
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p. 7679 - 7681
(2007/10/03)
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- Combining different hydrogen-bonding motifs to self-assemble interwoven superstructures
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A series of carboxyl-substituted dibenzylammonium salts have been cocrystallized with the macrocyclic polyethers dibenzo[24]crown-8 (DB24C8) and bis-p-phenylene[34]crown-10 (BPP34C10) to effect the noncovalent syntheses of a wide range of interwoven superstructures in the solid state. In all cases, the dibenzylammonium cations thread through the cavities of the macrocyclic polyethers - primarily as a result of N+-H ··· O hydrogen bonds, with occasional secondary stabilization from C - H ··· O and aryl-aryl interactions - to form pseudorotaxane complexes possessing supplementary recognition sites (specifically, carboxyl groups) for further intercomplex association through hydrogen bonding. One unit of each of the dibenzylammonium cations threads through the DB24C8 macrocycle to make single-stranded, carboxyl-containing [2]pseudorotaxanes that interact further with one another to produce novel supramolecular architectures as a result of hydrogen bonding between their carboxyl groups (the carboxyl dimer supramolecular synthon), or between carboxyl groups and polyether oxygen atoms. Elaborate architectures, such as side-/main-chain pseudopolyrotaxanes and a daisy-chain-like supramolecular array, were thus synthesized noncovalently. BPP34C10 can accommodate two cations within its macrocyclic interior to form carboxyl-containing [3]pseudorotaxanes in which BPP34C10 acts as a girdle that helps to control the spatial orientation of the carboxylic acid-containing recognition sites for additional intersupramolecular association through the carboxyl dimer. PF6/- anions were also found to play a role in the self-assembly processes. When the anions interact with the [3]pseudorotaxanes, these recognition sites are oriented in the same direction. This leads to the formation of doubly-encircled multicomponent supermolecules when BPP34C10 is cocrystallized with dibenzylammonium cations bearing only one carboxyl substituent. On the other hand, when BPP34C10 is cocrystallized with an isophthalic acid-substituted ammonium cation, there is no evidence of any anion assistance to self-assembly; the isophthalic acid units are aligned in opposite directions, creating an interwoven supramolecular cross-linked polymer.
- Ashton, Peter R.,Fyfe, Matthew C. T.,Hickingbottom, Sarah K.,Menzer, Stephan,Stoddart, J. Fraser,White, Andrew J. P.,Williams, David J.
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p. 577 - 589
(2007/10/03)
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- Selective self-assembly and acid-base controlled de-/rethreading of pseudorotaxanes constructed using multiple recognition motifs
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The selective self-assembly of a threadlike tetracation, containing two dialkylammonium (NH2/+) centers and a 4,4'-bipyridinium (bpym2+) unit, with an assortment of macrocyclic polyethers has been investigated. Spectroscop
- Ashton, Peter R.,Ballardini, Roberto,Balzani, Vincenzo,Fyfe, Matthew C.T.,Gandolfi, M. Teresa,Martínez-Díaz, M.-Victoria,Morosini, Marco,Schiavo, Cesare,Shibata, Kazusato,Stoddart, J. Fraser,White, Andrew J.P.,Williams, David J.
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p. 2332 - 2341
(2007/10/03)
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- Multiply stranded and multiply encircled pseudorotaxanes
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The self-assembly of four multicomponent rotaxane-like complexes, in which either (a) three or four dibenzo-[24]crown-8 rings encircle threadlike oligoammonium cations [PhCH2(NH2+CH2C6H4CH2
- Ashton, Peter R.,Fyfe, Matthew C. T.,Glink, Peter T.,Menzer, Stephan,Stoddart, J. Fraser,White, Andrew J. P.,Williams, David J.
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p. 12514 - 12524
(2007/10/03)
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- Thermodynamisch kontrollierte Selbstorganisation von Psudorotaxanen und Pseudopolyrotaxanen mit unterschiedlichen selbstselektiven Erkennungsmotiven
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Keywords: Kristall-Engineering; Kronenether; Molekulare Erkennung; Rotaxane; Selbstorganisation
- Ashton, Peter R.,Glink, Peter T.,Martinez-Diaz, M.-Victoria,Stoddart, J. Fraser,White, Andrew J. P.,Williams, David J.
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p. 2058 - 2061
(2007/10/03)
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