Synthetic Utility of 1-Bromoethene-1-sulfonyl Fluoride (BrESF): A Review

In the area of sulfur(VI) fluoride exchange (SuFEx) click chemistry, 1-bromoethene-1-sulfonyl fluoride (BrESF) has emerged as a versatile bifunctional building block. This review explores the unique reactivity of BrESF, which stems from its nature as a dipolarophile/dienophile, as an activated Michael acceptor and a vinyl halide. We discuss in detail the applications of BrESF in three organic transformations: cycloaddition reactions (including [3+2], [2+2], and Diels–Alder) for accessing diverse heterocyclic and aliphatic scaffolds; conjugate additions for creating sulfonyl derivatives; and transition-metal-catalyzed cross-couplings. The review highlights how BrESF enables late-stage functionalization of complex molecular architectures, providing an efficient route to “SuFExable” compounds essential for drug discovery and advanced materials science.