Palladium‐Catalyzed Methylation of Nitroarenes with Methanol
作者:Lin Wang、Helfried Neumann、Matthias Beller
DOI:10.1002/anie.201814146
日期:2019.4.8
procedure for the synthesis of N‐methyl‐arylamines directly from nitroarenes using methanol as green methylating agent was developed. The key to success is the use of a specific catalyst system consisting of palladium acetate and the ligand 1‐[2,6‐bis(isopropyl)phenyl]‐2‐[tert‐butyl(2‐pyridinyl)phosphino]‐1H‐Imidazole (L1). The generality of this protocol is demonstrated in the synthesis of more than 20
l-(+)-Tartaric acid and choline chloride based deep eutectic solvent: An efficient and reusable medium for synthesis of N-substituted pyrroles via Clauson-Kaas reaction
作者:Ping Wang、Fei-Ping Ma、Zhan-Hui Zhang
DOI:10.1016/j.molliq.2014.07.015
日期:2014.10
l-(+)-Tartaric acid–choline chloride based deep eutectic solvent has been found to be an effective promoted medium for Clauson-Kaas reaction of aromatic amines and 2,5-dimethoxytetrahydrofuran. Structurally diverse N-substituted pyrroles were obtained in high to excellent yields under mild conditions. The deep eutectic solvent is inexpensive, non-toxic, reusable and biodegradable.
The first general and regioselective Pd‐catalyzed cyclocarbonylation to give α‐methylene‐β‐lactones is reported. Key to the success for this process is the use of a specific sterically demanding phosphine ligand based on N‐arylated imidazole (L11) in the presence of Pd(MeCN)2Cl2 as pre‐catalyst. A variety of easily available alkynols provide under additive‐free conditions the corresponding α‐methylene‐β‐lactones
Palladium-Catalyzed Hydroxylation of Aryl Halides under Ambient Conditions
作者:Alexey G. Sergeev、Thomas Schulz、Christian Torborg、Anke Spannenberg、Helfried Neumann、Matthias Beller
DOI:10.1002/anie.200902148
日期:2009.9.28
temperature Pd‐catalyzed synthesis of phenols from aryl bromides and chlorides is presented. Stoichiometric studies of Pd‐mediated hydroxylation of arylhalides employing a bulky imidazolyl‐phosphine ligand and the novel palladium precursor [Pd(cod)(CH2SiMe3)2] led to development of efficient catalytic synthesis of phenols underambientconditions (see scheme; Ad=adamantyl, cod=1,5‐cyclooctadiene)
降低热量:介绍了第一种室温下Pd催化的由芳基溴化物和氯化物合成苯酚的方法。使用笨重的咪唑基膦配体和新型钯前体[Pd(cod)(CH 2 SiMe 3)2 ]进行的钯介导的芳基卤化物羟基化反应的化学计量研究导致了在环境条件下高效催化合成苯酚的过程(参见方案) ; Ad =金刚烷基,cod = 1,5-环辛二烯)。
Unique chemoselective Clauson–Kass reaction of substituted aniline catalyzed by MgI2 etherate
作者:Xingxian Zhang、Junchen Shi
DOI:10.1016/j.tet.2010.12.018
日期:2011.2
Clauson–Kass reaction of various substitutedaniline, primary aryl amide, and sufonyl amide with 2,5-dimethoxytetrahydrofuran was realized in the presence of 10 mol % of MgI2 etherate in a mild, efficient, and highly chemoselective manner. Iodide counterion and solvents (i.e., MeCN) played the critical roles for the unique reactivity of this catalytic system.