Catalyst-Dependent Divergent Synthesis of Pyrroles from 3-Alkynyl Imine Derivatives: A Noncarbonylative and Carbonylative Approach
作者:Gen-Qiang Chen、Xiao-Nan Zhang、Yin Wei、Xiang-Ying Tang、Min Shi
DOI:10.1002/anie.201405215
日期:2014.8.4
A novel Ru0‐ and RhI‐catalyzed noncarbonylative and carbonylative cycloisomerization of readily available 3‐alkynylimine derivatives has been developed to provide 3,4‐fused or nonfused pyrrole derivatives efficiently in moderate to excellent yields. The key steps involve the formation of a ruthenium carbenoid intermediate or a rhodacycle intermediate, respectively. In these reactions, CO can serve
Gold-Catalyzed Hydrative Carbocyclization of 1,5- and 1,6-Diyn-3-ones via an Oxygen Transfer Process
作者:Jhih-Meng Tang、Ting-An Liu、Rai-Shung Liu
DOI:10.1021/jo801753g
日期:2008.11.7
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.