One‐Step Synthesis of Trifluoroethylated Chromones via Radical Cascade Cyclization–Coupling of 2‐(Allyloxy)arylaldehydes

A transition‐metal‐free synthetic protocol involved with trifluoromethyl radical addition–cyclization of 2‐(allyloxy)arylaldehydes for a series of CF 3 ‐containing 3‐substituted chromenones formation has been developed. The radical cascade cyclization–coupling reaction can be run in a one‐step manner with Langlois′ reagent (CF 3 SO 2 Na) and K 2 S 2 O 8 . Broad scopes of substrates with various functional groups are evaluated in moderate to good efficacy under operational simplicity and mild reaction conditions. A plausible mechanism for the construction of trifluoroethylated chromones is proposed based on mechanistic studies.