First catalyst-free CO<sub>2</sub>trapping of<i>N</i>-acyliminium ions under ambient conditions: sustainable multicomponent synthesis of thia- and oxazolidinyl carbamates
carbon dioxide (CO2) and amine) is reported. This catalyst-free reaction provides a convenient and feasible approach to prepare N-acyl thia- and oxazolidinyl carbamates with good functional-group compatibility and high efficiency under green conditions. Furthermore, the multicomponent method features a broad substrate scope, facile product diversification, smooth scale-up and notable potential for polymer