Rapid CO2 coupling to propargylic alcohols: unlocking the production of α-alkylidene cyclic carbonates via continuous flow

α-Alkylidene cyclic carbonates (αCCs) are gaining interest as building blocks in organic and polymer chemistry. To date, their synthesis via the coupling of CO2 to propargylic alcohols has been restricted to batch processes, with extensive efforts devoted to improving catalytic systems. Herein, utilizing a refined, homogeneous silver-carbene-organobase catalytic system, we optimized batch conditions to achieve, for the first time, complete conversion of tertiary propargylic alcohols within minutes instead of hours. Building on this, we introduce a continuous flow methodology to produce a library of αCCs, achieving the highest space-time yields reported, with quantitative conversions in less than 20 minutes and outputs up to 111 grams per day. This approach reduces CO2 usage to 1 or 2 equivalents, improves parameter control, and is expected to facilitate scalability. In addition, “plug-and-play” lab-scale continuous flow modules enable seamless integration of subsequent αCC transformations without intermediate purification, as illustrated by the aminolysis of αCCs into oxazolidones with good conversion (91%). Furthermore, supporting the silver-carbene catalyst on a polymer matrix eliminates silver contamination and even suppresses the need for a base co-catalyst. This work advances the scalable synthesis of αCCs via continuous flow, marking a significant step toward greener, CO2-based cyclic carbonates and derivatives.