Novel and Highly Efficient Carboxylative Cyclization of CO2 to 2-Oxazolidinones Using Nano-SiO2-Supported Ionic Liquid Sustainable Catalysts.

The conversion of CO2 into 2-oxazolidinones through carboxylative cyclization with propargylic amines is considered an effective method for utilizing waste gas as a sustainable C1 resource and mitigating the greenhouse effect. In this context, a series of nano-SiO2-supported ionic liquids have been prepared and developed as multifunctional heterogeneous catalysts in the carboxylative cyclization of propargylic amines with CO2. The catalyst IL-SbF6@nano-SiO2 demonstrated a high compatibility with various propargylic amines, achieving excellent yields (90~98%) for the desired 2-oxazolidinones under mild conditions. Additionally, IL-SbF6@nano-SiO2 can be easily separated from the reaction mixture and reused for up to six cycles without any significant activity loss. This is important for sustainable chemistry, as it reduces waste and potentially lowers costs. This study offers novel insights into the development and design of green and efficient catalysts for the synthesis of 2-oxazolidinones from carbon dioxide.