three steps from N‐aryl fluorenone nitrones and methylenecyclopropanes through a [3+2] cycloaddition, reduction and subsequent acid‐catalyzed ring contraction cascade strategy under mild reaction conditions. Experimental studies showed that the stereochemistry remained intact after the ring contraction step. Furthermore, the obtained spirofluorenyl‐β‐lactam was easily converted to two novel spiroazetidine
在[3 + 2]环加成,还原和随后的酸催化环收缩级联策略下,在温和的反应条件下,从N-芳基
芴酮硝酮和
亚甲基环丙烷经过三个步骤,以中等收率制备了各种螺
芴基-β-内酰胺。实验研究表明,在环收缩步骤之后,立体
化学保持完整。此外,所获得的螺
芴基-β-内酰胺可以轻松转化为两个新型螺氮杂
环丁烷和螺
喹啉酮骨架,收率很高。