Electrophile-Induced Dearomatizing Spirocyclization of <i>N</i>-Arylisonicotinamides: A Route to Spirocyclic Piperidines

Treatment of N-arylisonicotinamides with trifluoromethanesulfonic anhydride triggers intramolecular nucleophilic attack of the aryl ring on the 4-position of the pyridinium intermediate. The products are spirocyclic dihydropyridines which can be converted to valuable spirocyclic piperidines related to biologically active molecules such as MK-677.将N-芳基异烟酰胺（N-arylisonicotinamides）与三氟甲磺酸酐（trifluoromethanesulfonic anhydride）进行反应时，可触发芳环对吡啶鎓中间体（pyridinium intermediate）4位的分子内亲核进攻。所得产物为螺环二氢吡啶（spirocyclic dihydropyridines）类化合物，该类产物可被转化为具有高价值的螺环哌啶（spirocyclic piperidines）类衍生物，其中包含与MK-677等生物活性分子相关的结构类似物。