Diastereoselective Construction Of Structurally Diverse Trifluoromethyl Bispiro-[Oxindole-Pyrrolidine-Chromanone]S Through [3+2] Cycloaddition Reactions

Herein we successfully developed a domino [3 + 2] cycloaddition of isatin-based (trifluoromethyl)imine ylides with benzylidenechromanones for the construction of a series of biologically important and structurally diverse bispiro-[oxindole-pyrrolidine-chromanone]s incorporating a CF3 motif under the organocatalyst DABCO catalysis. The reaction offers a straightforward and atom-economical procedure for the preparation of the desired products featuring four contiguous stereocenters including two vici-nally spiro quaternary stereocenters in moderate to good yields with high diastereoselectivity via an exo-transition state (up to 91 % yield and >20:1 diastereomeric ratio). Of note, this is the first example of the introduction of CF3 units into spirocyclic chromanone compounds, which might be valuable in medicinal chemistry. (C) 2021 Elsevier Ltd. All rights reserved.