Copper‐Catalyzed Three‐Component Reactions to Access Antitumor 5‐Methylseleno Triazoles

ABSTRACT A versatile copper‐catalyzed C‐H methylselenation/cyclization reaction of terminal alkynes with alkyl azides and PhSO 2 SeCH 3 has been developed for the synthesis of 5‐methylseleno triazoles. The antiproliferative activities of all resulting 5‐methylseleno triazoles were evaluated against HCT15 and HCT116 cell lines. Notably, compounds 4n and 5c exhibited up to 1000‐fold greater activity compared to 1,2,3‐triazoles, demonstrating that the introduction of the methylseleno functional group can significantly enhance antitumor activity.