Chemoselective Generation of the 1,3-Benzdiyne Synthon

Abstract A versatile 1,3-benzdiyne precursor is reported that enables chemoselective, sequential generation of aryne triple bonds on the same aromatic ring under mild conditions. This is achieved from a single aromatic ring bearing an iodonium unit─enabling access to one aryne triple bond via deprotonation─and a “Kobayashi”-type ortho-silylaryl triflate unit, from which the second aryne triple bond can be released using fluoride. Each triple bond undergoes regioselective trapping. DFT studies reveal high-to-very high levels of ground state distortion in each aryne system. The approach leverages the unique reactivity of arynes to construct the framework of prized fluoride-activated precursors used in the next step. This strategy grants modular access to otherwise difficult-to-generate 1,2,3,4-substitution motifs.