Umpolung-like Cross-coupling of Tosylhydrazones with 4-Hydroxy-2-pyridones under Palladium Catalysis
作者:Tania Katsina、Kyriaki Eleni Papoulidou、Alexandros L. Zografos
DOI:10.1021/acs.orglett.9b03119
日期:2019.10.4
Tosylhydrazones under palladium catalysis were found to perform cross-couplingreactions with 4-hydroxy-2-pyridones. The umpolung-like reactivity, between the α-carbon of tosylhydrazone and the 3-position of the heterocycle, which is observed in the obtained products, indicates the directed sp3-CH-activation of an alkylated phenol intermediate by the pendant 3-palladated heterocycle. The reaction and its intercepted
REGIOCHEMICAL CONTROL IN THE 1,2-CARBONYL TRANSPOSITION OF α,α′-DIMETHYLENE SYSTEMS THROUGH REGIOSELECTIVE SULFENYLATION OF TOSYLHYDRAZONE DIANIONS
作者:Tetsuya Mimura、Takeshi Nakai
DOI:10.1246/cl.1980.931
日期:1980.8.5
The regiochemical outcomes are described in the 1,2-carbonyl shift of α,α′-dimethylene systems which relies upon the regioselective sulfenylation of tosylhydrazone dianions leading to the enol thioethers of transposed ketones. Notably, a high regiospecificity was obtained with β-methyl- and β,β-dimethylcyclohexanone without any attempts to separate the stereoisomers of the hydrazones.
Vinyllithium reagents from arenesulfonylhydrazones
作者:A. Richard Chamberlin、Jeffrey E. Stemke、F. Thomas Bond
DOI:10.1021/jo00395a033
日期:1978.1
Copper-catalyzed tri- or tetrafunctionalization of alkenylboronic acids to prepare tetrahydrocarbazol-1-ones and indolo[2,3-<i>a</i>]carbazoles
作者:Hong-Yan Bi、Cheng-Jing Li、Cui Wei、Cui Liang、Dong-Liang Mo
DOI:10.1039/d0gc01514h
日期:——
We describe a cascade strategy for tri- or tetrafunctionalization of alkenylboronic acids to prepare diverse tetrahydrocarbazol-1-ones and indolo[2,3-a]carbazoles in good yields with N-hydroxybenzotriazin-4-one (HOOBT) and arylhydrazines as oxygen and nitrogen sources, respectively. Mechanistic studies reveal that the domino reaction undergoes the copper-catalyzed Chan–Lam reaction, [2,3]-rearrangement
我们描述了烯基硼酸的三或四官能化的级联策略,以制备具有N的高收率的各种四氢咔唑-1-酮和吲哚[2,3- a ]咔唑-羟基苯并三嗪-4-酮(HOOBT)和芳基肼分别作为氧和氮源。机理研究表明,多米诺反应在一锅法反应中经过五个步骤,经历了铜催化的Chan-Lam反应,[2,3]重排,亲核取代,氧化和顺序[3,3]重排。该反应显示出广泛的底物范围,并且可以耐受多种官能团。更重要的是,该反应易于以克为单位进行,并且产物可以通过简单的萃取,洗涤和重结晶进行纯化,而无需快速柱色谱。本协议的特点是易于获得的起始原料,高位标记的功能化,一锅中的五步串联,多个C–C / C–O / C–N键形成以及吲哚图案的多样性。