Preparation of Polyfunctional Arylmagnesium, Arylzinc, and Benzylic Zinc Reagents by Using Magnesium in the Presence of LiCl
作者:Fabian M. Piller、Albrecht Metzger、Matthias A. Schade、Benjamin A. Haag、Andrei Gavryushin、Paul Knochel
DOI:10.1002/chem.200900575
日期:2009.7.20
magnesium reagent with ZnCl2. This method can also be applied to the preparation of functionalized benzylic zinc reagents from benzylic chlorides. In the case of di‐ or tribromoaryl derivatives, directing groups such as ‐OPiv, ‐OTs, ‐N2NR2, or ‐OAc orient the zinc insertion (Zn/LiCl) to the ortho‐position, while the reaction with Mg/LiCl or Mg/LiCl/ZnCl2 leads to regioselective insertion into the para‐carbon–bromine
LiCl的存在极大地促进了镁向各种芳族和杂环溴化物中的插入。几个功能组,如-OBoc,-OTs,-Cl,-F,-CF 3,-OMe,-NMe 2和-N 2 NR 2,具有很好的耐受性。氰基的存在在某些情况下导致有机卤化物竞争性还原为相应的ArH化合物。通过ZnCl 2原位捕获中间镁试剂可以耐受甲基或乙基酯等敏感基团的存在。该方法也可用于由苄基氯化物制备官能化的苄基锌试剂。如果是二溴或三溴芳基衍生物,则应使用诸如-OPiv,-OTs,-N之类的指导基团2 NR 2或-OAc将锌插入(Zn / LiCl)定向到邻位,而与Mg / LiCl或Mg / LiCl / ZnCl 2的反应导致区域选择性插入对碳-溴键中。描述了所有金属化步骤的大规模实验(20–100 mmol)。
The transition-metal-catalyst-free oxidative homocoupling of organomanganese reagents prepared by the insertion of magnesium into organic halides in the presence of MnCl<sub>2</sub>·2LiCl
作者:Zhihua Peng、Na Li、Xinyang Sun、Fang Wang、Lanjian Xu、Cuiyu Jiang、Linhua Song、Zi-Feng Yan
DOI:10.1039/c4ob01235f
日期:——
An oxidative homocoupling of organomanganese reagents was performed in one pot without an additional transition-metal catalyst.
有机锰试剂的氧化自偶联在一个锅中进行,无需额外的过渡金属催化剂。
Functionalizations of Mixtures of Regioisomeric Aryllithium Compounds by Selective Trapping with Dichlorozirconocene
作者:Alicia Castelló-Micó、Simon A. Herbert、Thierry León、Thomas Bein、Paul Knochel
DOI:10.1002/anie.201508719
日期:2016.1.4
The reaction of mixtures of aryllithium regioisomers obtained either by directed lithiation or by Br/Li exchange with substoichiometric amounts of Cp2ZrCl2 proceeds with high regioselectivity. The least sterically hindered regioisomeric aryllithium is selectively transmetalated to the corresponding arylzirconium species leaving the more hindered aryllithium ready for various reactions with electrophiles
Radical Catalysis of Kumada Cross-Coupling Reactions Using Functionalized Grignard Reagents
作者:Georg Manolikakes、Paul Knochel
DOI:10.1002/anie.200803730
日期:2009.1
Palladium, radically different: A wide range of polyfunctional aryl‐ and heteroarylmagnesium reagents undergo fast Kumada cross‐couplings (see scheme) with functionalized aryl bromides in the presence of a palladium catalyst and an alkyl iodide as additive. These reactions proceed by a radical pathway.
Nickel or Iron Catalysed Carbon-Carbon Coupling Reaction of Arylenes, Alkenes and Alkines
申请人:knochel Paul
公开号:US20100184977A1
公开(公告)日:2010-07-22
Organozinc compounds of the type R
1
—Ar
1
—ZnY (1) can be reacted with different functionalized aryl halides R
2
—Ar
2
—X (2) in the presence of catalytic amounts of Ni or Fe in a polar solvent or solvent mixture to form polyfunctional biaryles of the type R
1
—Ar
1
—Ar
2
—R
2
(3). Organozinc compounds of the type (1) can be represented by the transmetallation reaction of functionalized aryl magnesium halides or lithium aryl compounds with e.g. ZnBr
2
.