A facile synthesis of pyrrolo-(di)-benzazocinones via an intramolecular N-acyliminium ion cyclisation
作者:Frank D. King、Abil E. Aliev、Stephen Caddick、Derek A. Tocher、Denis Courtier-Murias
DOI:10.1039/b815195d
日期:——
A facile, moderate to high yielding synthesis of hexahydro-(di)-benzazocinones is described via an intramolecular N-acyliminium ion cyclisation. The iminium ion intermediates are formed from the readily available 4,4-diethoxybutyl amides with an excess of triflic acid. For electron-withdrawing substituents, better yields were obtained from the pre-formed 2-hydroxypyrrolidine amides. From NMR studies
通过分子内N-酰基亚胺离子环化,描述了一种容易,中等至高产的六氢-(二)-苯甲佐酮合成。亚胺离子中间体由易于获得的过量4,4-二乙氧基丁基酰胺形成三氟甲磺酸。对于吸电子取代基,从预先形成的2-羟基吡咯烷酰胺获得了更好的产率。根据NMR研究,在室温下,吡咯并苯并三唑-3-酮以两种构象的缓慢平衡混合物形式存在。