Synthesis of β-oxopropylcarbamates in a recyclable AgBr/ionic liquid catalytic system: An efficient assembly of CO₂ under ambient pressure

A green and recyclable catalytic system based on AgBr and an ionic liquid (IL) was developed for the three-component coupling reaction of propargylic alcohols, secondary amines and carbon dioxide (CO₂). A series of target carbamates, especially those generated from challenging substrates, could be obtained smoothly at atmospheric CO₂ pressure in a straightforward one-pot process. Moreover, the catalyst loading reached the lowermost level ever reported. Particularly, this catalytic system exhibited robust constancy and could be reused at least 5 times with retention of high catalytic activity. It is worth noting that this is the first catalytic system which could be recycled successfully for this reaction.