1557-50-2Relevant academic research and scientific papers
Access to Chiral Seven-Member Cyclic Amines via Rh-Catalyzed Asymmetric Hydrogenation
Li, Pan,Huang, Yi,Hu, Xinquan,Dong, Xiu-Qin,Zhang, Xumu
, p. 3855 - 3858 (2017/07/26)
A highly efficient asymmetric hydrogenation of azepine/oxazepine-type seven-member cyclic imine hydrochlorides was successfully developed using Rh/bisphosphine-thiourea ligand ZhaoPhos, affording various chiral seven-member cyclic amines with full conversions, high yields, and excellent enantioselectivities (up to 96% yield, >99% ee). Additionally, this asymmetric hydrogenation can proceed well on gram scale with excellent ee value. Moreover, control experimental results displayed that the anion-bonding interaction between the chloride ion of the substrate and thiourea motif of the ZhaoPhos played an important role to obtain excellent enantioselectivity.
Mild and efficient palladium-catalyzed direct trifluoroethylation of aromatic systems by C-H activation
T?th, Balázs L.,Kovács, Szabolcs,Sályi, Gerg?,Novák, Zoltán
supporting information, p. 1988 - 1992 (2016/02/18)
The introduction of trifluoroalkyl groups into aromatic molecules is an important transformation in the field of organic and medicinal chemistry. However, the direct installation of fluoroalkyl groups onto aromatic molecules still represents a challenging and highly demanding synthetic task. Herein, a simple trifluoroethylation process that relies on the palladium-catalyzed C-H activation of aromatic compounds is described. With the utilization of a highly active trifluoroethyl(mesityl)iodonium salt, the developed catalytic method enables the first highly efficient and selective trifluoroethylation of aromatic compounds. The robust catalytic procedure provides the desired products in up to 95 % yield at 25 °C in 1.5 to 3 hours and tolerates a broad range of functional groups. The utilization of hypervalent reagents opens new synthetic possibilities for direct alkylations and fluoroalkylations in the field of transition-metal-catalyzed C-H activation.
Solvent free acid catalysed direct N-alkylation of amines with alcohols using Al grafted MCM-41
Tayade, Kamlesh N.,Mishra, Manish,Munusamy,Somani, Rajesh S.
, p. 91 - 96 (2014/06/24)
The catalytic activity of Al grafted MCM-41 (Al-MS) was explored for solvent free acid catalysed direct N-alkylation of amines using alcohols as green alkylating agent to establish a clean method for synthesis of N-alkylated amines. The study revealed that acidity of Al-MS catalyst, reaction conditions and substrate's (amines and alcohols) nature are important factors influencing the N-alkylation reaction. The Al grafted MCM-41 with Si/Al molar ratio of 5 showed excellent activity for N-alkylation of amines with alcohols. The reusability of spent catalyst regenerated by simple washing with acetone was demonstrated for subsequent four reaction cycles.
