Iron catalyzed cross coupling reactions of aromatic compounds
申请人:——
公开号:US20030220498A1
公开(公告)日:2003-11-27
A process for the production of compounds Ar—R
1
by means of a cross-coupling reaction of an organometallic reagent R
1
—M with an aromatic or heteroaromatic substrate Ar—X catalyzed by one or several iron salts or iron complexes as catalysts or pre-catalysts, present homogeneously or heterogeneously in the reaction mixture. This new invention exhibits substantial advantages over established cross coupling methodology using palladium- or nickel complexes as the catalysts. Most notable aspects are the fact that (i) expensive and/or toxic nobel metal catalysts are replaced by cheap, stable, commercially available and toxicologically benign iron salts or iron complexes as the catalysts or pre-catalysts, (ii) commercially attractive aryl chlorides as well as various aryl sulfonates can be used as starting materials, (iii) the reaction can be performed under “ligand-free” conditons, and (iv) the reaction times are usually very short.
Dilithium Amides as a Modular Bis-Anionic Ligand Platform for Iron-Catalyzed Cross-Coupling
作者:Peter G. N. Neate、Bufan Zhang、Jessica Conforti、William W. Brennessel、Michael L. Neidig
DOI:10.1021/acs.orglett.1c02053
日期:2021.8.6
Dilithium amides have been developed as a bespoke and general ligand for iron-catalyzed Kumada–Tamao–Corriu cross-coupling reactions, their design taking inspiration from previous mechanistic and structural studies. They allow for the cross-coupling of alkyl Grignard reagents with sp2-hybridized electrophiles as well as aryl Grignard reagents with sp3-hybridized electrophiles. This represents a rare
Alkylation of Pyridines at Their 4-Positions with Styrenes plus Yttrium Reagent or Benzyl Grignard Reagents
作者:Tomoya Mizumori、Takeshi Hata、Hirokazu Urabe
DOI:10.1002/chem.201404635
日期:2015.1.2
A new regioselective alkylation of pyridines at their 4‐position was achieved with styrenes in the presence of yttrium trichloride, BuLi, and diisobutylaluminium hydride (DIBAL‐H) in THF. Alternatively, similar products were more simply prepared from pyridines and benzyl Grignardreagents. These reactions are not only a useful preparation of 4‐substituted pyridines but are also complementary to other
Ir<sub>4</sub>(CO)<sub>12</sub>-Catalyzed Benzylic C(sp<sup>3</sup>)–H Silylation of 2-Alkylpyridines with Hydrosilanes Leading to 2-(1-Silylalkyl)pyridines
The iridium-catalyzed C(sp3)–H silylation of 2-alkylpyridines with hydrosilanes at the benzylic position to afford 2-(1-silylalkyl)pyridines is described. The low product yield was markedly improved by adding 3,5-dimethylpyridine. Norbornene is also an essential additive for the reaction to proceed as a hydrogen scavenger. Carbon monoxide plays an important role in the catalytic cycle as a ligand.
A Convenient Method for the Regioselective Synthesis of 4-Alkyl(aryl)pyridines Using Pyridinium Salts
作者:Kin-ya Akiba、Y\={u}ji Iseki、Makoto Wada
DOI:10.1246/bcsj.57.1994
日期:1984.7
(81–94%). The dihydropyridines were oxidized by oxygen to give 4-alkyl(aryl)pyridines (38–68%). Grignardreagents also reacted with 1-t-butyldimethylsilylpyridinium triflate with almost complete regioselectivity (>99%) to afford the corresponding 1,4-dihydropyridines, which were easily oxidized by oxygen to give 4-substituted pyridines in higher yields than above (58–70%).