Arenediazonium o-benzenedisulfonimides can be used as new and efficient reagents for Heck-type arylation reactions of some common substrates containing C–C multiple bonds, namely ethyl acrylate, acrylic acid, acroleyne, styrene and cyclopentene. The reactions were carried out in an organic solvent, in the presence of Pd(OAc)2 as pre-catalyst, and gave rise to arylated products, for example, ethyl cinnamates
Synthesis of Hexahydrocyclopenta[c]furans by an Intramolecular Iron-Catalyzed Ring Expansion Reaction
作者:Gerhard Hilt、Patrick Bolze、Maja Heitbaum、Katrin Hasse、Klaus Harms、Werner Massa
DOI:10.1002/adsc.200700035
日期:2007.8.6
The intramolecular iron-catalyzed ring expansionreaction of epoxyalkenes was investigated with a preformed iron(salen) [Fe(Salen)] complex. The formal insertion of the alkene into the epoxide generated hexahydrocyclopenta[c]furan derivatives in moderate to good yields and diastereoselectivities depending on other functional groups present in the starting materials. In addition, oxygen-tethered epoxyalkenes
用预先形成的铁(salen)[Fe(Salen)]配合物研究了环氧烯烃的分子内铁催化的环膨胀反应。取决于起始原料中存在的其他官能团,烯烃以中等至良好的产率和非对映选择性正式插入环氧化物生成的六氢环戊[ c ]呋喃衍生物中。另外,将氧束缚的环氧烯烃用于木脂素异构体的合成。讨论了Fe(Salen)催化反应过程的范围和局限性。
Brønsted Acid-Catalyzed Carbonyl-Olefin Metathesis inside a Self-Assembled Supramolecular Host
作者:Lorenzo Catti、Konrad Tiefenbacher
DOI:10.1002/anie.201712141
日期:2018.10.26
Carbonyl–olefin metathesis represents a powerful yet underdeveloped method for the formation of carbon–carbon bonds. So far, no Brønsted acid based method for the catalytic carbonyl–olefin metathesis has been described. Herein, a cocatalytic system based on a simple Brønsted acid (HCl) and a self‐assembled supramolecular host is presented. The developed system compares well with the current benchmark
The reaction of cyclic and open-chain diastereomerically pure secondary organoboranes with diisopropylzinc allows the preparation of secondary dialkylzinc reagents with good to excellent retention of configuration as shown by deuterolysis and CuI- and Pd0-mediated reactions with electrophiles. The importance of a high boron-zinc exchange rate to obtain high diastereoselectivity has been shown. Improvement
Achieving Vinylic Selectivity in Mizoroki-Heck Reaction of Cyclic Olefins
作者:Xiaojin Wu、Yunpeng Lu、Hajime Hirao、Jianrong Steve Zhou
DOI:10.1002/chem.201204427
日期:2013.5.3
In Heck reactions of cyclicolefins, the products usually have aryl groups that end up at the allylic and/or homoallylic position. We herein report new selectivity that adds aryl groups to the vinylic position. Cyclicolefins of various ring size worked well. The desired isomers were produced by palladium–hydride‐catalyzed isomerization of the initial products. Thus, a specific catalyst must be used