含有可阻转异构的膦-亚磷酸酯(P-OP)和手性C 2对称二胺(N-N)的RuCl 2(P-OP)(N-N)络合物(1)可以通过连续添加P轻松制备为反式异构体RuCl 2(PPh 3)3的–OP和N–N配体。对于这些络合物,已经观察到在室温下联芳基片段的快速阻转异构化。化合物反式- 1A干净异构成的混合物中的顺式异构体在EtOH在加热。DFT计算准确地再现了观察到的异构体的比例以及顺式的更大的热力学稳定性1a的异构体。配合物1是在非常温和的条件下,使用KO t Bu作为碱(4 bar H 2,室温,5 / 1 / KO t Bu = 500/1 / ,在非常温和的条件下,N-芳基亚胺5在甲苯中不对称氢化的有效催化剂前体。10)。在催化剂前体中,1f可在多种N-芳基亚胺的氢化反应中提供良好的对映选择性(84-96%ee,16个实例)。从DFT计算中,提出了一种机制,其中包括将氢化物和质子从二氢
An asymmetric reductive amination of ketones using both arylamines and benzhydrazide in the presence of nickel catalysts was developed. A one‐pot synthesis of tetrahydroquinoxalines was also developed starting directly from α‐ketoaldehydes and 1,2‐diaminobenzene. Formic acid was used as a safe and economic surrogate for high‐pressure hydrogen gas. Strongly σ‐donating bis(alkylphosphine)s are crucial
Highly Enantioselective Synthesis of Chiral Secondary Amines by Gold(I)/Chiral Brønsted Acid Catalyzed Tandem Intermolecular Hydroamination and Transfer Hydrogenation Reactions
作者:Xin-Yuan Liu、Chi-Ming Che
DOI:10.1021/ol901443b
日期:2009.9.17
A method for the synthesis of enantiomerically enriched secondary amines with excellent ee values through the tandem intermolecular hydroamination/transfer hydrogenation of alkynes using a “gold(I) complex−chiral Brønsted acid” protocol is developed. The catalysis works for a wide variety of aryl, alkenyl, and aliphatic alkynes as well as anilines with different electronic properties.