The 3-[2-(cyclohex-1-eneyl)ethyl]-[1,3]oxazoline-2,4-dione derivatives 9, 14 and 16 were subjected to hydride reduction followed by acid-catalyzed olefin-N-acyliminium ion cyclization to afford a series of perhydroisoquinolines 10, 11a, 11b, 19a-19c, 20a, 20b and 21. A mechanism was proposed that accounts for the observed stereoselectivity of the cyclization reactions based on the neighboring group participation by a benzoate group.
3-[2-(环己-1-烯基)乙基]-[1,3]噁唑-2,4-二酮衍生物9、14和16经过氢化还原后,接着进行酸催化的烯烃-N-酰亚胺离子环化反应,得到一系列的过氢化异喹啉10、11a、11b、19a-19c、20a、20b和21。提出了一种机理,解释了邻基参与的苯甲酸酯基对环化反应的立体选择性。