1,3-Dipolar cycloaddition to o-quinodimethanes has been observed for the first time in the reaction of pyrazole and isoxazole o-quinodimethanes 4–6 with the stable nitrile oxides 7 and 8. The products, dispiroisoxazolines 9–14, were isolated in moderate yields. In all cases the “anti” addition stereoisomers 9a–14a were formed, as was established by X-ray crystallographic analysis on 13a and 14a, whereas
1,3-偶极环加成到ö -quinodimethanes已经观察到在第一次中的反应
吡唑和
异恶唑ö -quinodimethanes 4-6与稳定
氧化腈7和8的产品,dispiroisoxazolines 9-14,在分离中等产量。在所有情况下,都形成了“抗”加成立体异构体9a-14a,这是通过对13a和14a进行X射线晶体学分析确定的,而仅在11b和13b的情况下才分离出“ syn”加成立体异构体。当
溴取代的邻
喹啉甲烷16使用单螺异异唑啉17和18。