Mechanochemical Synthesis of <i>X</i> ‐Vinylbenziodoxol(on)es and One‐Pot Conversion to Complex Alkenes ^**

Densely functionalized alkenes are often utilized as excellent tools for further functionalization of molecules. Recent progress in their synthesis includes nucleophilic addition to vinylbenziodoxolones (VBX) and vinylbenziodoxoles (VBO) to reach alkenes with complete regio- and stereocontrol. In this work, we leverage the inherent properties of mechanochemistry to enable an efficient transition metal-free one-pot route to 1,2-heteroatom-substituted (Z)-alkenes directly from ethynylbenziodoxol(on)es (EBX/EBO), avoiding the isolation of VBX/VBO. We demonstrate a high-yielding synthesis of a large variety of N/O/S-VBX reagents, which, combined with a telescoped nucleophilic addition, delivers a wide range of novel, complex (Z)-alkenes. This one-pot strategy would be challenging to develop in solution due to a mismatch in reaction solvents, and the unique mechanochemical activation offered by solventless, solid-state mixing also enables formation of products whose synthesis is inefficient with solvent-based methods.