Spiro[indoline-3,4′-piperidine] is a fundamental motif present in various biologically active compounds. Here, we report an intramolecular oxidative coupling reaction of oxindoles with β-dicarbonyls in the presence of a guanidinium hypoiodite catalyst, providing spiro-coupling products in moderate to excellent yields. Furthermore, a chiral hypoiodite catalyst derived from the chiral guanidinium organocatalyst is effective for the challenging asymmetric carbon–carbon bond-forming reaction, affording optically active spiro[indoline-3,4′-piperidines].

Hypoiodite is an environmentally friendly oxidant that has been developed to drive a variety of bond-forming reactions. Recently, asymmetric oxidative bond-forming reactions using hypoiodite in the presence of chiral onium organocatalysts have been used to synthesize carbon−heteroatom bonds, but asymmetric carbon−carbon bond-forming reactions have not been reported. Herein, we present an oxidative enolate coupling reaction of oxindoles to provide optically active oxindole dimers bearing consecutive all-carbon quaternary stereogenic centers, using a chiral guanidinium hypoiodite catalyst. This reaction affords the corresponding homocoupling products with high enantioselectivity. We also describe oxidative enolate cross-coupling reactions of two oxindoles bearing electronically distinct substituents.