High-Throughput Synthesis of (S)-α-Phellandrene through Three-Step Sequential Continuous-Flow Reactions

The combination of continuous-flow processing with heterogeneous catalysts allows for efficient, sustainable, multistep synthesis. Here, we report the continuous-flow synthesis of a valuable terpene product, phellandrene, from a readily available natural feedstock. The protocol consists of selective hydrogenation using a highly active and stable supported platinum catalyst, dehydrative hydrazone formation, followed by the Shapiro reaction. Appropriate design of the reactor allowed for high productivity and space–time yield. Phellandrene was synthesized on a 30-g scale over 6 h, giving high yields, purity, and productivity.