199186-68-0Relevant articles and documents
Low-Temperature Nickel-Catalyzed C?N Cross-Coupling via Kinetic Resolution Enabled by a Bulky and Flexible Chiral N-Heterocyclic Carbene Ligand
Hong, Xin,Shi, Shi-Liang,Wang, Zi-Chao,Xie, Pei-Pei,Xu, Youjun
supporting information, p. 16077 - 16084 (2021/06/17)
The transition-metal-catalyzed C?N cross-coupling has revolutionized the construction of amines. Despite the innovations of multiple generations of ligands to modulate the reactivity of the metal center, ligands for the low-temperature enantioselective amination of aryl halides remain a coveted target of catalyst engineering. Designs that promote one elementary reaction often create bottlenecks at other steps. We here report an unprecedented low-temperature (as low as ?50 °C), enantioselective Ni-catalyzed C?N cross-coupling of aryl chlorides with sterically hindered secondary amines via a kinetic resolution process (s factor up to >300). A bulky yet flexible chiral N-heterocyclic carbene (NHC) ligand is leveraged to drive both oxidative addition and reductive elimination with low barriers and control the enantioselectivity. Computational studies indicate that the rotations of multiple σ-bonds on the C2-symmetric chiral ligand adapt to the changing needs of catalytic processes. We expect this design would be widely applicable to diverse transition states to achieve other challenging metal-catalyzed asymmetric cross-coupling reactions.
Enantioselective hydrogenation of N-heteroaromatics catalyzed by chiral diphosphine modified binaphthyl palladium nanoparticles
Xia, Yun-Tao,Ma, Jing,Wang, Xiao-Dong,Yang, Lei,Wu, Lei
, p. 5515 - 5520 (2017/12/07)
The first application of binaphthyl-stabilized palladium nanoparticles (Bin-PdNPs) with chiral modifiers in asymmetric hydrogenation of N-heteroaromatics is revealed. With an appropriate ratio of R-BINAP/Bin-PdNPs used, the pre-prepared chiral nanocatalyst achieves asymmetric hydrogenations of 2-substituted quinolines with good to excellent yields and moderate enantioselectivities, which showed superior catalytic properties to the R-BINAP/Pd complex. Moreover, this protocol is also applicable to 2-substituted indoles.
Acylative kinetic resolution of racemic heterocyclic amines with (R)-2-phenoxypropionyl chloride
Vakarov, Sergey A.,Gruzdev, Dmitry A.,Chulakov, Evgeny N.,Sadretdinova, Liliya Sh.,Tumashov, Andrey A.,Pervova, Marina G.,Ezhikova, Marina A.,Kodess, Mikhail I.,Levit, Galina L.,Krasnov, Victor P.,Charushin, Valery N.
supporting information, p. 1231 - 1237 (2016/11/23)
The acylative kinetic resolution of racemic heterocyclic amines such as 3,4-dihydro-3-methyl-2H-[1,4]benzoxazines, 3,4-dihydro-3-methyl-2H-[1,4]benzothiazine, 2-methyl-1,2,3,4-tetrahydro-quinolines and 2-methylindoline with enantiopure (R)-2-phenoxypropionyl chloride has been studied. It has been found that acylation of 3,4-dihydro-3-methyl-2H-[1,4]benzothiazine proceeds with the best stereoselectively when compared with other racemic amines. An efficient method for the preparation of (S)-3,4-dihydro-3-methyl-2H-[1,4]benzothiazine (99.4% ee) via a kinetic resolution protocol was developed. The possibility of recycling (R)-2-phenoxypropionic acid has been demonstrated.
Low Pressure Asymmetric Hydrogenation of Quinolines using an Annulated Planar Chiral N-Ferrocenyl NHC-Iridium Complex
John, Joshni,Wilson-Konderka, Cody,Metallinos, Costa
, p. 2071 - 2081 (2015/06/23)
Annulated planar chiral N-ferrocenylimidazolones, obtained by acid-mediated cyclization of diphenylmethanol derivatives, may be reduced with diisobutylaluminium hydide (DIBAL-H) to afford a series of surprisingly stable and isolable hemiaminal ether aminals. Two of these derivatives can be oxidized with triphenylcarbenium tetrafluoroborate to imidazolinium salt precursors of N-heterocyclic carbenes (NHCs). Deprotonation of these salts in the presence of (cyclooctadiene)iridium chloride dimer {[Ir(COD)Cl]2} provides chiral coordination complexes bearing N-ferrocenyl NHCs with unique rigid tetracyclic frameworks. Cationic analogues of these complexes catalyze the asymmetric hydrogenation of 2-substituted quinolines under very mild conditions (1 mol% complex, 1 mol% PPh3, 1-5 atm H2, toluene, 25 C) in appreciable enantioselectivity (up to 90:10 er). The sensitivity of the hydrogenation process to changes in the phosphine additive suggests that an outer-sphere reaction mechanism may be involved, as proposed for a related achiral NHC-Ir complex reported by Crabtree and co-workers.
Efficient enantioselective hydrogenation of quinolines catalyzed by conjugated microporous polymers with embedded chiral BINAP ligand
Wang, Xu,Li, Jun,Lu, Shengmei,Liu, Yan,Li, Can
, p. 1170 - 1174 (2015/09/01)
Chiral Ir complexes were successfully used in the asymmetric hydrogenation of olefins, ketones, and quinolines. However, almost all the catalytic systems could not tolerate a high catalyst loading because of the formation of an irreversible iridium dimer and trimer during the reaction. It is expected that higher catalytic activity may be achieved if the Ir-complexes were isolated in space. The development of conjugated microporous polymers (CMPs) gives the opportunity for the spatial separation of the complexes. A series of chiral CMPs based on the chiral (R)-BINAP ligand (BINAP-CMPs) with different surface areas were synthesized. The BINAP ligands were separately distributed in the framework and were three times more active than the homogeneous catalyst (TOF 340 h-1 VS 100 h-1) for the asymmetric hydrogenation of quinolines.
N-tosyl-(S)-prolyl chloride in kinetic resolution of racemic heterocyclic amines
Gruzdev,Vakarov,Levit,Krasnov
, p. 1795 - 1807 (2014/05/06)
The kinetic resolution of racemic heterocyclic amines via acylation with N-tosyl-(S)-prolyl chloride was systematically investigated. It was established that racemic mixtures of aromatic amines could be resolved with high efficiency, while the acylation of 2- and 3-methylpiperidines occurred with low diastereoselectivity. A method for the preparation of enantiomerically pure (3R)-7,8-difluoro-3-methyl-3,4-dihydro-2H-[1,4]benzoxazine was developed.
The use of phosphite-type ligands in the Ir-catalyzed asymmetric hydrogenation of heterocyclic compounds
Lyubimov, Sergey E.,Ozolin, Dmitry V.,Ivanov, Pavel Yu,Melman, Artem,Velezheva, Valeriya S.,Davankov, Vadim A.
, p. 56 - 60 (2014/02/14)
A series of chiral phosphite-type ligands was tested in asymmetric Ir-catalyzed hydrogenation of quinolines and 2,4,5,6-tetrahydro-1H-pyrazino(3,2, 1-j,k)carbazole. Hydrogenation of quinaldine hydrochloride provided superior enantioselectivity up to 65% ee compared to quinaldine free base. The ligands were tested for the first time in the asymmetric Ir-Ircatalyzed hydrogenation of 2,4,5,6-tetrahydro-1H-pyrazino(3,2,1-j,k)carbazole yielding the antidepressant drug, pirlindole. Chirality 26:56-60, 2013. 2013 Wiley Periodicals, Inc.
A comparative study on the acylative kinetic resolution of racemic fluorinated and non-fluorinated 2-methyl-1,2,3,4-tetrahydroquinolines and 3,4-dihydro-3-methyl-2H-[1,4]benzoxazines
Gruzdev, Dmitry A.,Chulakov, Evgeny N.,Levit, Galina L.,Ezhikova, Marina A.,Kodess, Mikhail I.,Krasnov, Victor P.
, p. 1240 - 1246 (2013/10/22)
The acylative kinetic resolution of racemic 6-fluoro-2-methyl-1,2,3,4- tetrahydroquinoline, 7,8-difluoro-3,4-dihydro-3-methyl-2H-[1,4]benzoxazine, and their non-fluorinated analogues with (S)-naproxen and N-phthaloyl-(S)-amino acyl chlorides has been carried out. It has been shown that the presence of fluorine atoms in the aromatic fragment of a heterocyclic amine results in the increasing stereoselectivity of acylation with (S)-naproxen acyl chloride and in a decrease in the efficiency of acylative kinetic resolution using N-phthaloyl-(S)-amino acyl chlorides. A method for the preparation of enantiopure (S)-6-fluoro-2-methyl-1,2,3,4-tetrahydroquinoline (ee >99%) was developed.
A new electronically deficient atropisomeric diphosphine ligand (S)-CF 3O-BiPhep and its application in asymmetric hydrogenation
Zhang, De-Yang,Yu, Chang-Bin,Wang, Min-Can,Gao, Kai,Zhou, Yong-Gui
supporting information; experimental part, p. 2556 - 2559 (2012/06/15)
A new electronically deficient atropisomeric diphosphine ligand (S)-CF 3O-BiPhep was synthesized from 1-bromo-3-(trifluoromethoxy)benzene in high yield. The key steps included oxidative coupling with anhydrous ferric chloride and optical resolution by (+)-DMTA. The ligand afforded high performance for Ir-catalyzed asymmetric hydrogenation of quinolines with ee up to 92% and TON up to 25,000. It was also successfully applied to the Pd-catalyzed asymmetric hydrogenation of simple indoles with ee up to 87% and Rh-catalyzed asymmetric 1,4-addition of phenylboronic acid to 2-cyclohexenone with 97% ee.
Bronsted acid differentiated metal catalysis by kinetic discrimination
Rueping, Magnus,Koenigs, Rene M.
supporting information; experimental part, p. 304 - 306 (2011/03/17)
A Bronsted acid differentiated metal catalyzed hydrogenation has been developed. A combinatorial variation of chiral triflylamides with achiral metal complexes results in a highly active catalyst for the asymmetric reduction.
