- Decarboxylative sp 3 C-N coupling via dual copper and photoredox catalysis
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Over the past three decades, considerable progress has been made in the development of methods to construct sp 2 carbon-nitrogen (C-N) bonds using palladium, copper or nickel catalysis 1,2 . However, the incorporation of alkyl substrates to form sp 3 C-N bonds remains one of the major challenges in the field of cross-coupling chemistry. Here we demonstrate that the synergistic combination of copper catalysis and photoredox catalysis can provide a general platform from which to address this challenge. This cross-coupling system uses naturally abundant alkyl carboxylic acids and commercially available nitrogen nucleophiles as coupling partners. It is applicable to a wide variety of primary, secondary and tertiary alkyl carboxylic acids (through iodonium activation), as well as a vast array of nitrogen nucleophiles: nitrogen heterocycles, amides, sulfonamides and anilines can undergo C-N coupling to provide N-alkyl products in good to excellent efficiency, at room temperature and on short timescales (five minutes to one hour). We demonstrate that this C-N coupling protocol proceeds with high regioselectivity using substrates that contain several amine groups, and can also be applied to complex drug molecules, enabling the rapid construction of molecular complexity and the late-stage functionalization of bioactive pharmaceuticals.
- Liang, Yufan,Zhang, Xiaheng,MacMillan, David W. C.
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- Diazaborolyl-boryl push-pull systems with ethynylene-arylene bridges as 'turn-on' fluoride sensors
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Two linear π-conjugated systems with 1,3-diethyl-1,3,2-benzodiazaborolyl [C6H4(NEt)2B-] as a donor group and dimesitylboryl (-BMes2) as acceptor were synthesised with -ethynylene-phenylene- (-CC-1,4-C6H4-, 3) and -ethynylene-thiophene- (-CC-2,5-C4H2S- 12) bridges between the boron atoms. An assembly (20) consisting of two diazaborolyl-ethynylene- phenylene-boryl units, [C6H4(NCy)(N′)B-CC-1,4-C 6H4-BMes2] joined via a 1,4-phenylene unit at the nitrogen atoms (N′) of the diazaborolyl units was also synthesised. The three push-pull systems, 3, 12 and 20, form salts on fluoride addition with the BMes2 groups converted into (BMes2F)- anions. The molecular structures of 3, 12 and (NBu4)(12·F) were elucidated by X-ray diffraction analyses. The borylated systems 3, 12 and 20 show intense blue luminescence in cyclohexane with quantum yields (Φfl) of 0.99, 0.44 and 0.94, respectively, but weak blue-green luminescence in tetrahydrofuran (Φfl = 0.02-0.05). The charge transfer nature of these transitions is supported by TD-DFT computations with the CAM-B3LYP functional. Addition of tetrabutylammonium fluoride to tetrahydrofuran solutions of 3 and 20 resulted in strong violet-blue luminescence with emission intensities up to 46 times more than the emission intensities observed prior to fluoride addition. Compounds 3 and 20 are demonstrated here as remarkable 'turn-on' fluoride sensors in tetrahydrofuran solutions.
- Weber, Lothar,Eickhoff, Daniel,Kahlert, Jan,Boehling, Lena,Brockhinke, Andreas,Stammler, Hans-Georg,Neumann, Beate,Fox, Mark A.
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p. 10328 - 10346,19
(2020/08/31)
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- Fused indolines by palladium-catalyzed asymmetric C-C coupling involving an unactivated methylene group
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Selectivity at high temperatures: Bulky, thermally stable, chiral palladium complexes generated from N-heterocyclic carbenes (NHCs; see picture) were successfully applied to the synthesis of highly enantioenriched trans-fused indolines. Remarkably, this r
- Nakanishi, Masafumi,Katayev, Dmitry,Besnard, Celine,Kuendig, E. Peter
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p. 7438 - 7441
(2011/09/16)
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- Enantioselective synthesis of 2-methyl indolines by palladium catalysed asymmetric C(sp3)-H activation/cyclisation
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The first example of the enantioselective methyl C-H activation by an intramolecular ArPdX species and subsequent cyclisation was developed. Palladium catalysts using commercially available chiral diphosphines yield good ee's (up to 93% ee) in the synthesis of 2-methyl indolines from 2-halo N-isopropyl anilides. This approach was also employed for the synthesis of enantioenriched cyclohexyl fused indolines with moderate enantioselectivities.
- Anas, Saithalavi,Cordi, Alex,Kagan, Henri B.
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supporting information; experimental part
p. 11483 - 11485
(2011/11/13)
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- Transition Metal Complexes and Preparation Methods Thereof
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The present invention provides a novel mononuclear transition metal compound, a novel binuclear transition metal compound, a novel organic amine or phosphorous compound, and a method for preparing the same. The mononuclear transition metal compound accord
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Page/Page column 11-12
(2009/02/11)
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- CATALYST COMPOSITION COMPRISING GROUP 4 TRANSITION METAL COMPLEXES AND METHOD FOR PREPARING POLYOLEFINS USING THE SAME
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The present invention relates to a catalyst composition comprising a novel structure of a Group 4 transition metal compound, to a method for preparing the same, and to a method for preparing a polyolefin using the catalyst composition. The method for prep
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Page/Page column 18-19
(2010/11/28)
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- TRANSITION METAL COMPLEXES AND PREPARATION METHODS THEREOF
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The present invention provides a novel mononuclear transition metal compound, a novel binuclear transition metal compound, a novel organic amine or phosphorous compound, and a method for preparing the same. The mononuclear transition metal compound accord
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Page/Page column 25-26
(2010/11/28)
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- Rapid microwave-assisted reductive amination of ketones with anilines
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Using microwave technology, a new protocol has been developed that improves the reaction rate and overall efficiency of the direct reductive amination of ketones with anilines. When using sodium triacetoxyborohydride as the reducing agent, high product yi
- Bailey, Helen V.,Heaton, Wesley,Vicker, Nigel,Potter, Barry V. L.
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p. 2444 - 2448
(2008/02/10)
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- Palladium-catalyzed selective amination of haloaromatics on KF-alumina surface
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An efficient palladium-catalyzed amination, including polyaminations of aromatic bromides mediated on a surface of KF-alumina, is reported. The solvent-free one-pot protocol avoids the use of a strong base (sodium tert-butoxide) making it applicable to substrates containing a base-sensitive functional group. It proceeds without concomitant reductive bromination and provides access to selective amination of polyhaloaromatics.
- Basu, Basudeb,Das, Pralay,Nanda, Ashish K.,Das, Sajal,Sarkar, Sajal
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p. 1275 - 1278
(2007/10/03)
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