Giving the pharmacological importance of both benzofurans and δsultones, the development of efficient method for the construction of the δsultone fused benzofurans will be highly interesting to drug discovery and medicinal chemistry. Sulfur(Ⅵ) fluorides exchange (SuFEx) click chemistry that developed by Sharpless and coworkers has been established as a powerful and robust strategy for modular assembly of different sulfonyl-containing molecules. Interestingly, as one important type of SuFExable hub, βarylethenesulfonyl fluorides can be used as dienophiles to undergo annulative SuFEx reactions. Lupton and coworkers reported an Nheterocyclic carbene catalyzed [3+3] annulation of β-arylethenesulfonyl fluorides with trimethylsilyl enol ethers of 1,3-dicarbonyl compounds, which provided a novel organocatalytic method for the synthesis of δsultones. Later, Mayr and coworkers reported 10 that using excess of triethylamine, β-arylethenesulfonyl fluorides can react with dimedone to produce δ-sultone-fused cyclic enones. Recently, Qin and coworkers documented an interesting DBU-catalyzed annulative SuFEx reaction of β-arylethenesulfonyl fluorides and pyrazolones for the synthesis of δsultone fused pyrazoles. These fused heterocycles showed very interesting cholinesterase inhibitory activity and several products can be used as effective BuchE inhibitors. Using the similar strategy, the same group also reported a novel method for the synthesis of δ-sultone functionalized pyridines. Despite the progress made in this research field, the study of catalytic synthesis of δ-sultone fused heterocycles is still very limited. Very recently, we found that the combination of catalytic amount of organic superbase and molecular sieves 4Å can efficiently catalyze SuFEx reactions of different SuFExable hubs. We also found that this catalytic method can be used for the synthesis of functionalized δ-sultones and δ-sultone-fused heterocycles. In these reactions, molecular sieves 4Å was used as efficient HF scavenger instead of stoichiometric silicon additives and excess of bases. In line with our continuous study on SuFEx reactions, we proposed that βarylethenesulfonyl fluorides could undergo annulative SuFEx reaction with benzofuran-3(2H)-ones to form δ-sultone-fused benzofurans. Herein, we wish to report our results.