The<i>in situ</i>-Generated Nickel(0)-catalyzed Homo-coupling of Alkenyl Halides with Zinc Powder. A Specific Outcome in Stereochemistry
作者:Kentaro Takagi、Harutaka Mimura、Saburo Inokawa
DOI:10.1246/bcsj.57.3517
日期:1984.12
The catalytic activity of nickel(0) generated in situ from nickel(II) salt was examined in a dehalogenative coupling of alkenylhalides with zinc powder. The reaction of alkenyl bromides took place provided that potassium iodide was present to assist the reduction of nickel(II) with zinc powder, and also to convert the alkenyl bromides to the corresponding alkenyl iodides. A speculative view concerning
在烯基卤化物与锌粉的脱卤偶联中检测了从镍 (II) 盐原位生成的镍 (0) 的催化活性。烯基溴化物的反应发生,前提是存在碘化钾以帮助用锌粉还原镍 (II),并将烯基溴化物转化为相应的烯基碘化物。为了解释观察到的独特立体化学,提出了关于歧化步骤的推测性观点。
NICKEL-CATALYZED ULLMANN-TYPE COUPLING OF ALKENYL HALIDES WITH ZINC POWDER
作者:Kentaro Takagi、Naomi Hayama
DOI:10.1246/cl.1983.637
日期:1983.5.5
Convenient procedure for an Ullmann-type coupling of alkenyl halides using zinc powder, nickel(II) chloride, and potassium iodide and/or thiourea is presented. One double bond in the produced diene retained the configuration of a starting material, while partial cis–trans isomerization was observed in the second one.
作者:Roland U. Braun、Markus Ansorge、Thomas J. J. Müller
DOI:10.1002/chem.200600530
日期:2006.12.4
coupling of electron-deficient (hetero)aryl halides 1 and (hetero)aryl or alkenyl 1-propargyl alcohols 2 does not terminate at the stage of the expected internal propargyl alcohols, but rather gives rise to the formation of alpha,beta-unsaturated ketones 3 with a variety of acceptor substituents. This new domino reaction, a coupling-isomerization reaction (CIR), can be rationalized as a sequence of
-2(5H)-furanones and 6-substituted 5-iodo-2(2H)-pyranones in which these last compounds are the major products. The 5-iodo-2(2H)-pyranones, which are easily separated chromatographically from the corresponding regioisomers, are able to undergo Stille-type reactions with a variety of organotin compounds to give 5,6-disubstituted 2(2H)-pyranones in moderate to good yields. One of these compounds, i.e
Twofold Carbon-Carbon Bond Formation by Intra- and Intermolecular Radical Reactions of Aryl Diazonium Salts
作者:Hannelore Jasch、Yannick Landais、Markus R. Heinrich
DOI:10.1002/chem.201300354
日期:2013.6.24
Cascade reactions: A variety of novel cascade reactions can be performed when the known and well‐studied radical 5‐ or 6‐exo‐cyclization of an aryldiazonium salt is conducted in the presence of alkenes and further optional scavengers (see scheme).