and kinetically competent catalysts for this transformation. The fleeting transmetalation intermediate has been successfully synthesized through an alternative synthetic organometallic pathway at lower temperature, allowing for in situ NMR study of the C–N bond reductive elimination step. This study addresses key factors governing the mechanism of the nickel-catalyzed Buchwald–Hartwig amination process
The Ni-catalyzed cross-coupling reaction between aryl fluorides and primary amines was enabled by the 1,2-bis(dicyclohexylphosphino)benzene (DCYPBz) or 1,2-bis(dicyclohexylphosphino)ethane (DCYPE) ligands. Both N-alkyl- and N-aryl-substituted primary amines participated in the selective reaction to form secondary amines. This protocol would potentially be useful for late-stage diversification of fluorinated
Simple, Efficient Catalyst System for the Palladium-Catalyzed Amination of Aryl Chlorides, Bromides, and Triflates
作者:John P. Wolfe、Hiroshi Tomori、Joseph P. Sadighi、Jingjun Yin、Stephen L. Buchwald
DOI:10.1021/jo991699y
日期:2000.2.1
Palladium complexes supported by (o-biphenyl)P(t-Bu)(2) (3) or (o-biphenyl)PCy2 (4) are efficient catalysts for the catalytic amination of a wide variety of aryl halides and triflates. Use of ligand 3 allows for the room-temperature catalytic amination of many aryl chloride, bromide, and triflate substrates, while ligand 4 is effective for the amination of functionalized substrates or reactions of acyclic secondary amines. The catalysts perform well for a large number of different substrate combinations at 80-110 degrees C, including chloropyridines and functionalized aryl halides and triflates using 0.5-1.0 mol % Pd; some reactions proceed efficiently at low catalyst levels (0.05 mol % Pd). These ligands are effective for almost all substrate combinations that have been previously reported with various other ligands, and they represent the most generally effective catalyst system reported to date. Ligands 3 and 4 are air-stable, crystalline solids that are commercially available. Their effectiveness is believed to be due to a combination of steric and electronic properties that promote oxidative addition, Pd-N bond formation, and reductive elimination.
Potassium iodide catalysed monoalkylation of anilines under microwave irradiation
作者:Juan L. Romera、José M. Cid、Andrés A. Trabanco
DOI:10.1016/j.tetlet.2004.10.002
日期:2004.11
A potassium iodide catalysed method for the selective N-monoalkylation anilines with alkylhalides and alkyltosylates under microwave irradiation is described. The corresponding N-alkylanilines are obtained in good yields with only minor quantities of dialkylation by-products. (C) 2004 Elsevier Ltd. All rights reserved.