作者:H.E. Schoemeker、Tj. Boer-Terpstra、J. Dukink、W.N. Speckamp
DOI:10.1016/0040-4020(80)85036-8
日期:1980.1
Cyclisation of acetylenic ethoxylactams 1b-12b leads to bridgehead nitrogen bicyclic ketones in excellent yields. The reaction is weakly acid-catalysed and proceeds at ambient temperature. The observed regioselectivity effect is discussed in terms of stability of exo vs endo vinyl cations and ring strain effects. The high yield conversion of N-(5-hexynyl)-ethoxy lactams 7b and 8b in the 5/8 and 6/8
炔基乙氧基内酰胺1b-12b的环化可产生极高收率的桥头氮双环酮。该反应是弱酸催化的,并在环境温度下进行。根据外型对内乙烯基阳离子的稳定性和环应变效应,讨论了观察到的区域选择性效应。在5/8和6/8稠合的双环酮内酰胺7c和8c中N-(5-己炔基)-乙氧基内酰胺7b和8b的高产率转化值得特别注意。