PhI(OAc)2-Promoted Regioselective Cycloaddition of N-Aminopyridinium Ylides with Electron-Deficient Alkenes

Herein, we report a regioselective cycloaddition strategy of N-aminopyridinium ylides with electron-deficient alkenes, in the presence of a hypervalent iodine reagent, PhI(OAc)2. A variety of multi-functionalized pyrazolo[1,5-a]pyridine architectures were smoothly afforded by , the reactions of pyridine-, quinoline- and isoquinoline-based N-ylides with diverse alkenes with or without a halogen atom adjacent to the electron-withdrawing group (EWG) under facile conditions.