Continuous‐Flow Visible Light Organophotocatalysis for Direct Arylation of 2H‐Indazoles: Fast Access to Drug Molecules

A continuous‐flow homogeneous photocatalytic method has been devised for the direct arylation of 2H‐indazoles. This visible‐light‐promoted approach directly accesses a wide range of structurally diverse C3‐arylated scaffolds of biological interest in a fast (1 min), single‐step reaction by using eosin Y as an organophotocatalyst. Furthermore, a microreactor technology is also employed for the fast synthesis of liver X receptor inhibitor drugs with very good yields under metal‐free conditions, whereas the reported methods required multiple steps and much longer reaction times (18–24 h). Lights, catalyst, action! A continuous‐flow homogeneous photocatalytic method has been devised for the direct arylation of 2H‐indazoles. This visible‐light‐promoted approach directly accesses a wide range of structurally diverse C3‐arylated scaffolds of biological interest in a fast, single‐step synthesis with eosin Y as a catalyst. A microreactor is employed for the fast synthesis of liver X receptor inhibitor drugs with very good yields.