104480-59-3Relevant academic research and scientific papers
Enantioselective α-arylation of cyclic ketones catalyzed by a combination of an unmodified Cinchona alkaloid and a palladium complex
Richter, Christian,Ranganath, Kalluri V. S.,Glorius, Frank
, p. 377 - 382 (2012)
A palladium/Cinchona alkaloid-catalyzed α-arylation between cyclic ketones and aryl halides under phosphine-free conditions is presented. The use of a simple, unmodified Cinchona alkaloid results in high levels of activity and selectivity with up to 93% ee. These enantioinduction levels are comparable or even higher than the ones reported using palladium/BINAP complexes. To the best of our knowledge, this represents the first use of unmodified Cinchona alkaloids as ligands/catalysts in asymmetric transition metal complex-catalyzed cross-coupling reactions. Copyright
Nickel-catalyzed enantioselective C-C bond formation through C sp 2 -O cleavage in aryl esters
Cornella, Josep,Jackson, Evan P.,Martin, Ruben
, p. 4075 - 4078 (2015)
We report the first enantioselective C-C bond formation through C-O bond cleavage using aryl ester counterparts. This method is characterized by its wide substrate scope and results in the formation of quaternary stereogenic centers with high yields and asymmetric induction.
Enantioselective Intramolecular Hydroacylation of Unactivated Alkenes: An NHC-Catalyzed Robust and Versatile Formation of Cyclic Chiral Ketones
Janssen-Müller, Daniel,Schedler, Michael,Fleige, Mirco,Daniliuc, Constantin G.,Glorius, Frank
, p. 12492 - 12496 (2015/10/12)
A highly enantioselective intramolecular N-heterocyclic carbene (NHC)-catalyzed hydroacylation reaction gives access to a range of cyclic ketones from unactivated olefin-substituted aldehydes (up to 99% ee). Remarkably, aliphatic aldehydes were also transformed efficiently in an NHC-catalyzed hydroacylation reaction for the first time. 100% Organic: A highly enantioselective N-heterocyclic carbene (NHC)-catalyzed intramolecular hydroacylation of aromatic and, more interestingly, aliphatic aldehydes with unactivated olefins offers access to a range of cyclic α-chiral ketones bearing quaternary centers. The reaction was found to be highly robust and proceeds with excellent yield in the presence of a diverse range of functional groups.
Enantioselective α-arylation of ketones with aryl triflates catalyzed by difluorphos complexes of palladium and nickel
Liao, Xuebin,Weng, Zhiqiang,Hartwig, John F.
, p. 195 - 200 (2008/09/21)
The asymmetric α-arylation of ketones with aryl triflates is described, and the use of this electrophile with nickel and palladium catalysts containing a segphos derivative increases substantially the scope of highly enantioselective arylations of ketone enolates. The combination of aryl triflates as reactant, difluorphos as ligand, palladium catalysts for reactions of electron-neutral or electron-rich aryl triflates, and nickel catalysts for reactions of electron-poor aryl triflates led to a series of α-arylations of tetralone, indanone, cyclopentanone, and cyclohexanone derivatives. Enantioselectivities ranged from 70% to 98% with 10 examples over 90%. Systematic studies on these α-arylations have revealed a number of factors that affect enantioselectivity. Ligands containing biaryl backbones with smaller dihedral angles generate catalysts that react with higher enantioselectivity than related ligands with larger dihedral angles. In addition, faster rates for reactions of aryl triflates versus those for reactions of aryl bromides allow the α-arylations of aryl triflates to be conducted at lower temperatures, and this lower temperature improves enantioselectivity. Finally, studies that compare the enantioselectivities of catalytic reactions to those of stoichiometric reactions of isolated [(segphos)Pd(Ar)(Br)], [(segphos)Pd(Ar)(I)], and [(segphos)Ni(C 6H4-4-CN)Br] suggest that catalyst decomposition affects enantioselectivity.
