Strategic Approach on <i>N</i>
-Oxides in Gold Catalysis - A Case Study
作者:Jasmin Schießl、Philipp M. Stein、Judith Stirn、Kirsten Emler、Matthias Rudolph、Frank Rominger、A. Stephen K. Hashmi
DOI:10.1002/adsc.201801007
日期:2019.2.19
An extensive kinetic study of selected key reactions of (oxidative) goldcatalysis concentrates on the decrease of the catalytic activity due to inhibition of the gold(I) catalyst caused by pyridine derivatives that are obtained as by‐products if N‐oxides are applied as oxygen donors. The choice of the examined pyridine derivatives and their corresponding N‐oxides has been made regardless of their
对(氧化)金催化的选定关键反应的广泛动力学研究集中在催化活性的降低,这是由于吡啶衍生物引起的金(I)催化剂的抑制,如果使用N氧化物作为副产物获得的吡啶衍生物氧气供体。不管它们的市售性如何,都已对受检吡啶衍生物及其相应的N-氧化物进行了选择。特别注意的是迄今为止在大多数反应筛选中都被忽略的实际益处。用GC和1监测测试反应1 H NMR光谱。所接收的反应常数提供了关于杂环的电子结构与催化活性之间的相关性的信息。根据收集的动力学数据,有可能开发出一套基本的三种N氧化物,这些氧化物必须在进一步的氧化金(I)催化反应中加以考虑。
Iodine/TBHP-Promoted One-Pot Deoxygenation and Direct 2-Sulfonylation of Quinoline<i>N</i>-Oxides with Sodium Sulfinates: Facile and Regioselective Synthesis of 2-Sulfonylquinolines
A highly efficient iodine/TBHP-mediated one-pot deoxygenative and regioselective C2-sulfonylation of quinoline N-oxides with sodium sulfinate salts has been developed. This metal, base and phosphorus-free protocol employs readily accessible and easy to handle reagents, and can be conveniently carried out at room temperature under mild conditions, providing an alternative access to a series of C2 sulfonyl
Palladium-Catalyzed Oxygenative Cross-Coupling of Ynamides and Benzyl Bromides by Carbene Migratory Insertion
作者:Yunpeng Gao、Guojiao Wu、Qi Zhou、Jianbo Wang
DOI:10.1002/anie.201712795
日期:2018.3.1
A palladium‐catalyzed oxygenative cross‐coupling of ynamides and benzyl bromides has been developed. After subsequent hydrogenation, α,α‐disubstituted amide derivatives were obtained in good yields. Migratory insertion of α‐oxo palladium carbene species, generated by intermolecular oxidation, is proposed as the key step in this reaction. The study demonstrates the potential of ynamides to serve as
Gold-Catalyzed Highly Regioselective Oxidation of C−C Triple Bonds without Acid Additives: Propargyl Moieties as Masked α,β-Unsaturated Carbonyls
作者:Biao Lu、Chaoqun Li、Liming Zhang
DOI:10.1021/ja1072614
日期:2010.10.13
Gold-catalyzed intermolecular oxidations of internal alkynes have been achieved with high regioselectivities using 8-alkylquinoline N-oxides as oxidants and in the absence of acid additives. Synthetically versatile α,β-unsaturated carbonyls are obtained in good to excellent yields and with excellent E-selectivities. A range of functional groups such as THP, MOMO, N(3), OTBS, and N-Boc are tolerated
使用 8-烷基喹啉 N-氧化物作为氧化剂并且在没有酸添加剂的情况下,已经以高区域选择性实现了内部炔烃的金催化分子间氧化。合成通用的 α,β-不饱和羰基化合物以良好到极好的收率和极好的 E 选择性获得。可以容忍一系列功能组,例如 THP、MOMO、N(3)、OTBS 和 N-Boc。该反应允许 α,β-不饱和羰基被掩蔽为炔丙基部分,从而为复杂结构合成中可能遇到的这些官能团的相容性问题提供了实用的解决方案。
Synthesis of heteroaromatic trifluoromethyl ethers with trifluoromethyl triflate as the source of the trifluoromethoxy group
作者:Qing-Wei Zhang、John F. Hartwig
DOI:10.1039/c8cc05084h
日期:——
A series of nitrogen-heterocycles have been transformed to the corresponding trifluoromethyl or higher perfluoroalkyl ethers by reaction of the corresponding N-oxides with trifluoromethyl or higher perfluoroalkyl triflate. Trifluoromethyl triflate, which has generally been used as a precursor to [OCF3]−, is used here as a bifunctional reagent to render the heteroarene more electrophilic and to deliver