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Potassium carbonate-catalyzed (3 + 2) cycloaddition reaction between N -2,2,2-trifluoroethylisatin ketimines and azodicarboxylates has been developed, constructing a series of novel N -heterocycle infused spirooxindoles in good to excellent yields (up to 98%) under milder conditions. The presence of both biologically active oxindole and trifluoromethyl-1,2,4-triazoline moieties in these novel spirocyclic compounds would provide new lead structures in the discovery of heterocyclic compounds with potential pharmaceutical activities.

Six 8-oxoprotoberberines were synthesized collectively in four steps with acceptable yields (14-19%), of which the products 8-oxopalmatine, 8-oxopseudopalmatine, 8-oxoberberine, and 8-oxopseudoberberine come from nature. The synthetic route was featured with the In(OTf) 3 -catalyzed cyclization and Heck coupling. Moreover, the syntheses of the natural products berberine, canadine, and iambertine were achieved via various reductions from 8-oxoberberine, which provided a concise approach to the syntheses of this kind of alkaloids.

Herein, we report an unprecedented intramolecular cross-nucleophile coupling strategy of indole tethered β-amino acrylates using a catalyst system combining λ 3 -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.