First Bromide‐Catalyzed Selenylation of 2‐Alkyn‐1‐One <i>O</i>‐Methyloximes Enabled the Synthesis of 4‐Selenylated Isoxazoles

Abstract A series of 3,5‐diaryl‐4‐selanylisoxazoles were synthesized in 56–97% yields (most cases&gt;80% yield), which was first accomplished via bromide‐catalyzed selenylation of 2‐alkyn‐1‐one O ‐methyloximes using element Se and boronic acids as the selenyl source. Compared to traditional strategies, this method proceeded under simple catalytic system. Broad substrate scope, good functional group compatibility, metal‐free conditions, and easy operation was showed in this protocol. Additionally, this method was easily amendable to gram‐scale reaction and synthetic transformations. Furthermore, preliminary mechanistic experiments demonstrated that a radical pathway was possibly involved in this work.