Michael/Cyclization Tandem Reaction of 3-Formylchromones with Isothiocyanatooxindoles

As the core structure of a variety of natural products and drug molecules, polycyclic chromanone compounds possess many pharmacological activities such as anticancer, anti-inflammatory, antibacterial and neuroprotective, so they have attracted the attention of many organic chemists. The construction of chromanone compounds based on chromone derivatives can further enrich the molecular library of chromanone structure, filling the research gap on chromone compounds. In this paper, a Michael/cyclization tandem reaction was carried out with 3-formylchromones and 3-isothiocyanatooxindoles to produce the corresponding spirocyclic heterocycles with high yields (up to 92%) and excellent diastereoselectivities (up to >20:1 dr). Based on the reaction, a series of pyrrolidinyl spirooxindole-chromanones with three continuous stereocenters and a tetrasubstituted carbon were successfully constructed, and some asymmetric catalytic reaction conditions of the reaction were also preliminarily explored.