777-38-8Relevant articles and documents
Atomic Pt-Catalyzed Heterogeneous Anti-Markovnikov C-N Formation: Pt10Activating N-H for Pt1δ+-Activated C-C Attack
Ma, Xiaodan,An, Zhe,Song, Hongyan,Shu, Xin,Xiang, Xu,He, Jing
, p. 9017 - 9027 (2020/12/23)
C-N formation is of great significance to synthetic chemistry, as N-containing products are widely used in chemistry, medicine, and biology. Addition of an amine to an unsaturated carbon-carbon bond is a simple yet effective route to produce new C-N bonds. But how to effectively conduct an anti-Markovnikov addition with high selectivity has been a great challenge. Here, we proposed a strategy for highly regioselective C-N addition via hydroamination by using supported Pt. It has been identified that atomic-scale Pt is the active site for C-N addition with Pt12+ for Markovnikov C-N formation and atomic Pt (Pt1δ+ and Pt10) contributing to anti-Markovnikov C-N formation. A selectivity of up to 92% to the anti-Markovnikov product has been achieved with atomic Pt in the addition of styrene and pyrrolidine. A cooperating catalysis for the anti-Markovnikov C-N formation between Pt1δ+ and Pt10 has been revealed. The reaction mechanism has been studied by EPR spectra and in situ FT-IR spectra of adsorption/desorption of styrene and/or pyrrolidine. It has been demonstrated that Pt10 activates amine to be electrophilic, while Pt1δ+ activates C-C by π-bonding to make β-C nucleophilic. The attack of nucleophilic β-C to electrophilic amine affords the anti-Markovnikov addition. This strategy proves highly effective to a variety of substrates in anti-Markovnikov C-N formation, including aromatic/aliphatic amines reacting with aromatic olefins, aromatic/aliphatic olefins with aromatic amines, and linear aliphatic olefins with secondary aliphatic amines. It is believed that the results provide evidence for the function of varied chemical states in monatomic catalysis.
Direct Reductive Amination of Carbonyl Compounds with H2 Using Heterogeneous Catalysts in Continuous Flow as an Alternative to N-Alkylation with Alkyl Halides
Laroche, Benjamin,Ishitani, Haruro,Kobayashi, Shū
supporting information, p. 4699 - 4704 (2018/12/04)
A general continuous-flow procedure for direct reductive amination of secondary and primary amines with aromatic and aliphatic aldehydes as well as ketones is reported. The use of hydrogen gas and commercially available Pt/C as a heterogeneous catalyst is a key. In addition to exhibiting an excellent functional group tolerance, this method allows the fast formation of C?N bonds without production of any hazardous chemical waste. Applications to the synthesis of key intermediates toward active pharmaceutical ingredients (Donepezil and Arformoterol/Tamsulosin) are also described. (Figure presented.).
Efficient and chemoselective reduction of pyridines to tetrahydropyridines and piperidines via rhodium-catalyzed transfer hydrogenation
Wu, Jianjun,Tang, Weijun,Pettman, Alan,Xiao, Jianliang
, p. 35 - 40 (2013/03/13)
Promoted by iodide anion the rhodium complex dimer, [Cp RhCl 2]2, catalyzes efficiently the transfer hydrogenation of various quaternary pyridinium salts under mild conditions, affording not only piperidines but also 1,2,3,6-tetrahydropyridines in a highly chemoselective fashion, depending on the substitution pattern at the pyridinium ring. The reduction is conducted in azeotropic formic acid/triethylamine (HCOOH-Et 3N) mixture at 40 °C, with catalyst loadings as low as 0.005mol% being feasible. Copyright
