expedient method was demonstrated for the synthesis of 3‐alkenyl‐3‐amino‐2‐oxindoles from readily available propargylic alcohols and isatin imines in the presence of BF3 ⋅ Et2O as a catalyst under open‐air atmosphere. The above reaction was time‐dependent and further extended to the one‐pot synthesis of highly substituted spiro‐indeneindolones via 1,3‐amino group migration/Friedel‐Crafts cyclization. This
short reaction time, operational simplicity, and highly efficient reaction system. This protocol, which produces water as the only byproduct, provides efficient and atom-economical access to a class of fascinating quinoline and isoquinoline products in satisfactory yields. The method is effective on the gram scale, thus highlighting the inherent practicality of this methodology.
介绍了一种新的、绿色的、无过渡金属的方案,用于在Na 2 S 2 O 8存在下,从容易获得且对环境无害的喹啉和异喹啉N-氧化物与炔丙醇开始,用于轻松修饰喹啉和异喹啉衍生物或 K 2 S 2 O 8在 100°C。一锅转化具有官能团相容性好、反应时间短、操作简单、反应体系高效等优点。该协议产生水作为唯一的副产品,提供了以令人满意的收率获得一类引人入胜的喹啉和异喹啉产品的高效和原子经济的途径。该方法在克尺度上是有效的,从而突出了该方法的内在实用性。
Synthesis of 1,6-Dihydropyridine-3-carbonitrile Derivatives <i>via</i> Lewis Acid-Catalyzed Annulation of Propargylic Alcohols with (<i>E</i>)-3-Amino-3-phenylacrylonitriles
作者:Li-Juan Du、Yuecheng Zhang、Hong-Yu Zhang、Guohui Yin、Xiao-Yan Wang、Jiquan Zhao、Ya-Ping Han
DOI:10.1021/acs.joc.0c01171
日期:2020.8.7
acid-catalyzed, highly efficient, practical, and atom-economical protocol for the synthesis of functionalized 1,2-dihydropyridine-3-carbonitrile derivatives in the presence of Bi(OTf)3 (10 mol %) in tetrahydrofuran (2.0 mL) at 80 °C for 8 h in air is described, starting from readily accessed propargylic alcohols and (E)-3-amino-3-phenylacrylonitriles. This cycloaddition protocol, which is scalable and
An unambiguous and precise method for the synthesis of 3,1-benzoxathiin-4-ones/1,3-benzodioxin-4-ones by the reaction of propargylic alcohols and salicylic/thiosalicylic acids under a catalyst-free and open-air atmosphere is described.
Brønsted acid−catalyzed synthesis of tetrasubstituted allenes and polysubstituted 2H-chromenes from tertiary propargylic alcohols
作者:Natalia Cabrera-Lobera、Noelia Velasco、Roberto Sanz、Manuel A. Fernández-Rodríguez
DOI:10.1016/j.tet.2019.05.023
日期:2019.8
A practical and environmentally benign Brønstedacid−catalyzed protocol for the preparation of all-carbon tetrasubstituted allenes, consisting in the direct SNˈ addition of tri- or dimethoxy arenes or allyltrimethylsilane to tertiary propargylic alcohols, has been developed. In addition, a straightforward synthesis of densely substituted 2H-chromenes by metal-free tandem allenylation/heterocyclization