Lewis base-catalyzed [3 + 2] annulation of β-oxo-acrylamides with acyl isothiocyanates: facile access to 2-iminothiazolidin-4-one derivatives

A novel and efficient protocol for the Cs2CO3-catalyzed [3 + 2] annulation of β-oxo-acrylamides with acyl isothiocyanates has been developed under mild reaction conditions. This strategy offers a streamlined route to access 2-iminothiazolidin-4-one derivatives with yields of 53–83 %. The annulation is characterized by being transition-metal-free, atom-economic, and operationally straightforward.