Cobalt-Catalyzed Preparation of N-Heterocyclic Organozinc Reagents from the Corresponding Heteroaryl Chlorides
作者:Paul Knochel、Alexander Kremsmair、Simon Graßl、Christoph J. B. Seifert、Edouard Godineau
DOI:10.1055/a-1534-0624
日期:2021.11
Various substituted and unsubstituted N-heteroaryl chlorides have been converted into their corresponding organozinc species using zinc dust in the presence of zinc pivalate and 10% CoCl2 in benzonitrile at 25 °C. The resulting heteroarylzinc reagents were obtained in 43–98% yield within 9–48 h and reacted with a broad range of electrophiles, leading to the functionalized heteroarenes.
作者:Mario Ellwart、Ilya S. Makarov、Florian Achrainer、Hendrik Zipse、Paul Knochel
DOI:10.1002/anie.201603923
日期:2016.8.22
Readily prepared allylic zinc halides undergo SN2‐type substitutions with allylic bromides in a 1:1 mixture of THF and DMPU providing 1,5‐dienes regioselectively. The allylic zinc species reacts at the most branched end (γ‐position) of the allylic system furnishing exclusively γ,α′‐allyl–allyl cross‐coupling products. Remarkably, the double bond stereochemistry of the allylic halide is maintained during
现成的烯丙基卤化锌在THF和DMPU的1:1混合物中用烯丙基溴进行S N 2型取代,可选择性地提供1,5二烯。烯丙基锌物种在烯丙基体系的最分支末端(γ位置)反应,专门提供γ,α'-烯丙基-烯丙基交叉偶联产物。值得注意的是,烯丙基卤的双键立体化学在交叉偶联过程中得以保持。还可以耐受几个官能团(酯,腈)。烯丙基锌试剂的这种交叉偶联可以扩展到炔丙基和苄基卤化物。DFT计算显示了氯化锂在该替代中的重要性。
Copper-Catalyzed Asymmetric Allylic Alkylation of Racemic Cyclic Substrates: Application of Dynamic Kinetic Asymmetric Transformation (DYKAT)
作者:Jean-Baptiste Langlois、Alexandre Alexakis
DOI:10.1002/adsc.200900790
日期:2010.2.15
The copper-catalyzedasymmetricallylicalkylation (AAA) is of great interest in organic synthesis. This reaction was extensively studied using a broad range of substrates, ligands and organometallic reagents. However, the use of racemic substrates was still limited. Although some processes of kinetic resolution are reported in the literature, no examples of quantitative deracemization are described
Synthesis of Indolines and Derivatives by Aza‐Heck Cyclization
作者:Feiyang Xu、Katerina M. Korch、Donald A. Watson
DOI:10.1002/anie.201907758
日期:2019.9.16
For the first time, an aza-Heck cyclization that allows the preparation of indoline scaffolds is described. Using N-hydroxy anilines as electrophiles, which can be easily accessed from the corresponding nitroarenes, this method provides indolines bearing pendant functionality and complex ring topologies. Synthesis of challenging indolines, such as those bearing fully substituted carbon atoms at C2
Préparation des organozinciques dérivés de l'α-bromométhyl acrylate d'éthyle et de ses homologues
作者:Najat El Alami、Chantal Belaud、Jean Villiéras
DOI:10.1016/0022-328x(88)80333-4
日期:1988.6
α-bromoalkyl acrylates (aliphatic and alicyclic) results in high yields when carried out on 30 mesh activated granular zinc, between 14 and 20°C in ethereal solvents (THF, DME, ether). Under these conditions duplication can be minimized (5–15%) especially with t-butyl acrylates. These α-functional allylic organozinc derivatives have been characterized by hydrolysis and coupling with benzaldehyde.