在氮原子上被不同的π-亲核试剂取代的噻唑烷二酮3-8的区域选择性NaBH 4 / H +还原以良好的产率提供羟基内酰胺9-14。后面的化合物是α-酰化铵离子16的极好的前体,可以在HCOOH中进行立体选择环化,以产生具有不同结构的新型杂环系统。由于闭环中的立体电子控制,很容易实现立体选择性合成,例如8a到24的转换。
Parham-type cyclization and nucleophilic addition - N-acyliminium ion cyclization sequences for the construction of the isoquinoline nucleus
作者:M.Isabel Collado、Nuria Sotomayor、María-Jesús Villa、Esther Lete
DOI:10.1016/0040-4039(96)01321-4
日期:1996.8
Efficient methodologies based on the nucleophilic addition-N-acyliminium ioncyclization and the Parham-typecyclizationsequences of N-phenethylimides 1 and 2 are reported for the synthesis of a variety of heterocyclic systems: benzo[a]quinolizidones and their 2-oxa analogs, isoindoloisoquinolones, dibenzo[a,h]quinolizidones, thiazolo-, oxazolo-, and imidazolo [4,3-a]isoquinolones.