5-Endo-dig iodocyclisations of alk-3-yn-1,2-diols 4, followed by in situ dehydration, lead to good yields of beta-iodofurans 5, which can subsequently be converted into a wide range of derivatives 6-13, using transition metal-catalysed coupling reactions or halogen-metal exchange.
Synthesis of 2,5-Disubstituted 3-Iodofurans via Palladium-Catalyzed Coupling and Iodocyclization of Terminal Alkynes
作者:Zhengwang Chen、Gao Huang、Huanfeng Jiang、Huawen Huang、Xiaoyan Pan
DOI:10.1021/jo1023987
日期:2011.2.18
2,5-Disubstituted 3-iodofurans are readily prepared under very mild reaction conditions by the palladium/copper-catalyzed cross-coupling of (Z)-β-bromoenol acetates and terminal alkynes, followed by iodocyclization. The useful intermediates conjugated enyne acetates are obtained in high yields in the transformation. Aryl- and alkyl-substituted alkynes undergo iodocyclization in good yields. The resulting
Magnesium iodide promoted defluorinative reactions of 2,2-difluorocyclopropyl aryl ketones with aryl imines: A new, general synthesis of 2-alkylideneazetidines
作者:Wei Xu、Ion Ghiviriga、Qing-Yun Chen、William R. Dolbier
DOI:10.1016/j.jfluchem.2010.06.021
日期:2010.9
Upon treatment with anhydrous MgI2, 2,2-difluorocyclopropyl aryl ketones undergo a ring-opening process leading to complete loss of fluorine. When carried out in the presence of aryl imines, the reaction leads to a novel synthesis of 2-alkylideneazetidenes. A fluorine-free allenyl ketone is proposed as an intermediate in these reactions. (C) 2010 Published by Elsevier B.V.