Aryl iodane-induced cascade arylation–1,2-silyl shift–heterocyclization of propargylsilanes under copper catalysis

A novel copper-catalyzed arylation strategy for propargylsilanes utilizing diaryl-λ³-iodanes has been developed, enabling a cascade sequence involving 1,2-silyl migration and heterocyclization. The β-silicon effect facilitates the formation of stabilized allyl cation intermediates that undergo regioselective trapping by internal <i>O</i>- and <i>N</i>-nucleophiles furnishing functionalized heterocycles. This method provides access to tetrahydrofuran or pyrrolidine frameworks, each bearing a trifunctionalized (<i>E</i>)-configured vinyl side chain. The use of a shorter linker provides entry to 1,2,3,6-tetrahydropyridines. Additionally, in the absence of internal nucleophiles, this methodology yields aryl-substituted 1,3-dienes. This work introduces a palladium-free, single-step alternative to multistep heterocycle construction from propargylsilanes and highlights the synthetic potential of iodane-mediated carbofunctionalization under copper catalysis.