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-promoted hydration and sequential intramolecular aldol condensation reactions 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
(1Z)-1-(2,2-二甲基亚丙基)-1H-异苯并呋喃双(三氟甲基磺酰基)酰胺是通过空间阻碍的邻炔基二苯甲酮和双(三氟甲基磺酰基)亚胺(Tf2NH)之间的5-外环化反应合成的。证实五元环异苯并呋喃酰胺异构化以定量产率得到相应的苯并吡喃酰胺,即六元环骨架化合物。在环境温度下用 Tf2NH 处理较少阻碍的邻炔基二苯甲酮导致酸促进的水合和连续的分子内醇醛缩合反应,以良好的产率提供 3-芳基-1H-inden-1-one 衍生物。所提出的反应机理得到了 4-氯-和 5-甲氧基-2-乙炔基二苯甲酮衍生物作为底物与 Tf2NH 的反应行为的强烈支持,