Carboxylation of Aryl Triflates with CO<sub>2</sub> Merging Palladium and Visible-Light-Photoredox Catalysts
作者:Samir Kumar Bhunia、Pritha Das、Shantanu Nandi、Ranjan Jana
DOI:10.1021/acs.orglett.9b01532
日期:2019.6.21
visible-light-promoted, highly practical carboxylation of readily accessible aryl triflates at ambient temperature and a balloon pressure of CO2 by the combined use of palladium and photoredox Ir(III) catalysts. Strikingly, the stoichiometric metallic reductant is replaced by a nonmetallic amine reductant providing an environmentally benign carboxylation process. In addition, one-potsynthesis of a carboxylic
Development of an Air-Stable Nickel Precatalyst for the Amination of Aryl Chlorides, Sulfamates, Mesylates, and Triflates
作者:Nathaniel H. Park、Georgiy Teverovskiy、Stephen L. Buchwald
DOI:10.1021/ol403209k
日期:2014.1.3
A new air-stablenickelprecatalyst for C–Ncross-coupling is reported. The developed catalyst system displays a greatly improved substrate scope for C–N bond formation to include both a wide range of aryl and heteroaryl electrophiles and aryl, heteroaryl, and alkylamines. The catalyst system is also compatible with a weak base, allowing the amination of substrates containing base-sensitive functional
styrene and vinylarenes, the aryl and vinyl groups routinely insert at the β position. However, selective insertion at the αposition has been very rare. Herein, we provide a missing piece in the palette of Heck reaction, which gave >20:1 αselectivity. The key to our success is a new ferrocene 1,1′‐bisphosphane (dnpf) that carries 1‐naphthyl groups. Our mechanistic studies revealed that the high α selectivity
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
An Enantioselective, Intermolecular α-Arylation of Ester Enolates To Form Tertiary Stereocenters
作者:Zhiyan Huang、Zheng Liu、Jianrong (Steve) Zhou
DOI:10.1021/ja2066829
日期:2011.10.12
asymmetric α-arylation of carbonylcompounds, formation of tertiary centers with high enantioselectivity is a longstanding problem, due to easy enolization of the monoarylation products. Herein, we report such examples using a palladium catalyst supported by a new, (R)-H(8)-BINOL-derived monophosphine. Silyl ketene acetals, together with a weakly basic activator, were used as equivalents of ester anions
在过渡金属催化的羰基化合物的不对称α-芳基化中,由于单芳基化产物容易烯醇化,形成具有高对映选择性的三级中心是一个长期存在的问题。在此,我们报告了使用由新的 (R)-H(8)-BINOL 衍生的单膦支持的钯催化剂的示例。甲硅烷基乙烯酮缩醛与弱碱性活化剂一起用作酯阴离子的等价物,它们与芳基三氟甲磺酸酯以优异的对映体过量 (ee) 顺利反应。该反应的有效性在 92% ee 的 (S)-萘普生的克级合成中得到证明。