Advances of α-Activated Cyclic Isothiocyanate for Enantioselective Construction of Spirocycles

The efficient and enantioselective synthesis of pharmaceutically important spirocycles has attracted the focus of organic and medicinal chemists. In this context, with the excellent reactivity of α-activated isothiocyanate as formal 1,3-dipoles in the (3+2) cyclization process, the cyclic isothiocyanates featuring important pharmacophores, such as oxindole, pyrazolone, and indanone moieties, have emerged as powerful precursors to access to a variety of spirocycles with highly structural diversities. In addition, facile transformations of these spirocycles also showed potential applications in drug design. This review will cover the recent advances of α-activated cyclic isothiocyanates in enantioselective construction of spirocycles since 2015, also with the applications of corresponding products in organic and medicinal chemistry.