A Silver‐Catalyzed Modular Intermolecular Access to 6,6‐Spiroketals
作者:Alexander Ahrens、Niklas F. Heinrich、Simon R. Kohl、Martha Hokamp、Matthias Rudolph、Frank Rominger、A. Stephen K. Hashmi
DOI:10.1002/adsc.201900988
日期:2019.12.17
A modular synthesis of 6,6‐spiroketals via silver catalysis is reported. By combining an intermolecular Michael addition and a 6‐endo‐dig cyclization, this cascade reaction allows the modular preparation of highly substituted 6,6‐spiroketals by combining two substrate molecules. Established methods accessing this interesting substructure are complemented by this new transformation. The protocol tolerates
A visible-light-induced cascade reaction of 2-vinyloxy arylalkynes with thiosulfonates was developed and provided unexpected thio-substituted dibenzofuranderivatives in moderate yields. Mechanistic studies revealed the thiosulfonylation product of 2-vinyloxy arylalkyne was the key intermediate, and the additive disulfide played the role of hydrogen abstraction in the aromatization process to offer
Radical-Triggered Tandem Cyclization of 1,6-Enynes with H<sub>2</sub>O: A Way to Access Strained 1<i>H</i>-Cyclopropa[<i>b</i>]naph thalene-2,7-diones
作者:Limeng Zheng、Bingwei Zhou、Hongwei Jin、Ting Li、Yunkui Liu
DOI:10.1021/acs.orglett.8b03007
日期:2018.11.16
developed herein. Strained 1H-cyclopropa[b]naphthalene-2,7-diones are successfully obtained in moderate to good yields with excellent stereoselectivity. Mechanistic studies reveal a key role of water in generating a hydroxyl radical that initiates a sequential Michaeladdition/ring closure pathway. Importantly, the formed hydroxyl is proposed to be a good leaving group during the cyclopropane ring formation
本文已经开发了自由基引发的1,6-烯炔的串联环化。以中等至良好的产率和优异的立体选择性成功获得了应变的1 H-环丙烷[ b ]萘-2,7-二酮。机理研究揭示了水在产生羟基自由基中的关键作用,该羟基自由基引发了顺序的迈克尔加成/环闭合路径。重要的是,提议的形成的羟基在环丙烷环形成期间是良好的离去基团。
Copper-Catalyzed Intramolecular Oxidative 6-exo-trig Cyclization of 1,6-Enynes with H2O and O2
作者:Zhi-Qiang Wang、Wen-Wu Zhang、Lu-Bin Gong、Ri-Yuan Tang、Xu-Heng Yang、Yu Liu、Jin-Heng Li
DOI:10.1002/anie.201104082
日期:2011.9.12
The novel CuCl2‐catalyzed title reaction of enynes has been developed for synthesizing substituted naphthoquinones (see scheme; DMA=dimethylacetamide). The method represents the first example of a copper‐catalyzed enyne oxidative cyclization for constructing 1,4‐naphthoquinones by the incorporation of two oxygen atoms into the organic framework from molecular oxygen and water.
Fused Benzo[b]fluorenols: Palladium-Catalyzed Intramolecular Dehydroaromatization and Carbonyl Reduction
作者:Quansheng Zhao、Qiong Hu、Lei Wen、Min Wu、Yimin Hu
DOI:10.1002/adsc.201200108
日期:2012.8.13
Benzo[b]fluorenols were prepared by a new palladium-catalyzed one-pot reaction of en-one-ynes with 3-bromoprop-1-yne through intramoleculardehydroaromatization and carbonylreduction.
苯并[ b ]芴醇是通过一种新的钯催化的一键式炔与3-溴丙-1-炔的一锅法通过分子内脱氢芳构化和羰基还原反应制得的。