Synthesis of indenones via palladium-catalyzed annulation of internal alkynes
摘要:
A number of 2,3-disubstituted 1-indenones have been prepared in fair to good yields by treating o-iodo- or o-bromobenzaldehyde with various internal alkynes in the presence of a palladium catalyst. Synthetically, the methodology provides an especially convenient route to stable hindered indenones containing aryl, silyl, and tert-alkyl groups. The reaction is believed to proceed through a palladium-(IV) intermediate, and the regiochemistry of the reaction is controlled sterically.
A new approach for the synthesis of indenone derivatives using I2-promoted cyclization of ortho-alkynylarylketones has been developed. This method provides a metal-free and convenient route for regioselective synthesis of indenones employing ortho-alkynylarylketones with predefined substituents to obtain indenone products in moderate to good yields.
The First Formation of (1<i>Z</i>)-1-Alkylidene-1<i>H</i>-isobenzofuranium Amides and 1<i>H</i>-Inden-1-ones: Acid-Promoted 5-<i>exo</i>Cyclization and Hydration/Aldol Condensation Reactions of<i>o</i>-Ethynylbenzophenones
作者:Noriyoshi Nagahora、Tatsuya Wasano、Kazuhiro Nozaki、Tamaki Ogawa、Shuhei Nishijima、Daiki Motomatsu、Kosei Shioji、Kentaro Okuma
DOI:10.1002/ejoc.201301599
日期:2014.3
ambient temperature resulted in acid-promotedhydration and sequential intramolecular aldolcondensationreactions to afford 3-aryl-1H-inden-1-one derivatives in good yields. The proposed reaction mechanism was strongly supported by the reaction behaviour of 4-chloro- and 5-methoxy-2-ethynylbenzophenone derivatives as substrates with Tf2NH, leading to the formation of the corresponding 3-aryl-1H-inden-1-ones
Molecular iodine mediated cyclization reactions of 2-(1-alkynyl)benzylic alcohols to substituted indenones
作者:Chengyu Wang、Jingyu Yang、Xingcan Cheng、Ende Li、Yanzhong Li
DOI:10.1016/j.tetlet.2012.06.030
日期:2012.8
efficient I-2-mediated approach to the synthesis of disubstituted indenones from readily available 2-alkynylbenzyl alcohols in the presence of H2O has been developed. These results are different from the known iodocyclization reactions in which O-containing heterocycles are obtained. (c) 2012 Elsevier Ltd. All rights reserved.