Gold-Catalyzed Hydrative Carbocyclization of 1,5- and 1,6-Diyn-3-ones via an Oxygen Transfer Process
摘要:
This study reports new hydrative carbocyclizations of 1,5- and 1,6-diyn-3-ones catalyzed by PPh3AuOTf, involving a pi-alkyne-assisted oxygen transfer in the reaction mechanisms. Treatment of 2-(alk-2-yn-1-onyl)-1-alkynylbenzenes with PPh3AuOTf (5 mol %) in wet 1,4-dioxane (23 degrees C, 10 min) led to hydrative aromatization to give 4-hydroxyl-1-naphthyl ketones efficiently. This approach is also extendible to the hydrative cyclization of acyclic 1,5-diyn-3-ones, which afforded 4-cyclopentenonyl ketones in reasonable yields. On the basis of this oxygen-labeling study, we propose a plausible mechanism involving an alkyne-assisted oxygen transfer to generate key oxonium and gold-enolate intermediates.
TBAF-Catalyzed Cyclization Reactions of <i>o</i>
-(Alkynyl)phenyl Propargyl Alcohols with Malonate Esters: A Possible Cation-π Interaction as The Activation Approach
作者:Yulei Zhao、Xuqiang Guo、Zongkang Wang、Duyi Shen、Tingting Chen、Nan Wu、Shina Yan、Jinmao You
DOI:10.1002/ejoc.201901790
日期:2020.2.28
method has been devised for the synthesis of dihydroisobenzofuran derivatives through the reaction of in situ generated ynones with potentially C‐nucleophilic malonate esters. Both the basicity of fluoride anion and ammonium cation–π interaction with alkyne unit might play a crucial role in the cyclization reaction.
Synthesis of Polysubstituted Naphthofurans and Indenofurans Based on a Regiodivergent Intramolecular Carbometalation Strategy with 2‐(2’‐Alkynylaryl)‐3‐iodofurans
作者:Azusa Kondoh、Kohei Aita、Masahiro Terada
DOI:10.1002/chem.202300132
日期:——
Efficient methods for the synthesis of two types of furan-fused tricyclic compounds were developed based on a regiodivergent intramolecular carbometalation strategy using 2-(2’-alkynylaryl)-3-iodofurans as a common substrate. The methods involving the 6-endo-anti carbocupration or the formal intramolecular 5-exo-anti carbopalladation provide new access to a wide range of well-organized polysubstituted
基于使用 2-(2'-炔基芳基)-3-碘呋喃作为常见底物的区域发散分子内碳金属化策略,开发了两种类型的呋喃稠合三环化合物的有效合成方法。涉及 6-endo- anti carbocupration 或正式分子内 5-exo- anti carbopalladation的方法为广泛的组织良好的多取代萘并[1,2- b ]呋喃和茚并[1,2- b ]提供了新途径否则难以获得的呋喃。