λ3-Iodane/Lewis Acid Mediated Intramolecular Cross-Nucleophile Coupling of β-Amino Acrylates: Chemodivergent Syntheses of Indole Alkaloidal Frameworks

Herein, we report an unprecedented intramolecular cross-nucleophile coupling strategy of indole tethered β-amino acrylates using a catalyst system combining λ³-iodanes and Lewis acids to achieve the chemodivergent synthesis of three unique alkaloid skeletons. It was worth noting that the acquisition of spiroindolenines and azepino[4,5-b]indoles derivatives was switchable with choice of the Lewis acids. Moreover, the polycyclic spiroindolines containing a lactone fragment could also be accessed for the first time via cross-nucleophile coupling cascade intramolecular condensation sequence.