Construction of spirothioureas having an amino quaternary stereogenic center via a [3 + 2] annulation of 3-isothiocyanato oxindoles with 2-aminoacrylates

Abstract

A useful and convenient strategy for the diastereoselective synthesis of spirothioureas having an amino quaternary stereogenic center via a [3 + 2] annulation of 3-isothiocyanato oxindoles with 2-aminoacrylates was established. A diverse set of spirooxindole derivatives were synthesized in good to excellent yields and diastereoselectivities. Good enantioselectivities (up to 96 : 4 er) were obtained in the subsequent asymmetric study.