Synthesis of (<i>Z</i>)‑Enediynes\nvia Stereoinvertive Nucleophilic Substitution of (<i>E</i>)‑Sulfonylethenes with Arylethynide, and Their Aggregation-Induced\nOptical Properties

(<i>Z</i>)-Enediynes were successfully synthesized\nfrom\na trio of terminal ethynes through consecutive three-step reactions:\niodosulfonylation of ethyne with I<sub>2</sub>/PhSO<sub>2</sub>Na,\nfollowed by ethynylations of iodo and sulfonyl moieties of the resulting\niodosulfonylethene via Sonogashira−Hagihara coupling and nucleophilic\naddition–elimination, respectively. The molecular structure\nof the obtained (<i>Z</i>)-enediyne was fully characterized\nby X-ray crystal structure analysis, revealing that the nucleophilic\nsubstitution of (<i>E</i>)-sulfonylethene with arylethynide\nunderwent a selective stereoinversion. The (<i>Z</i>)-enediynes\nexhibited photoluminescence in both the solution and solid states\n(crystals and powders). Ph<sub>2</sub>N-substituted derivatives showed\nremarkable solvatofluorochromism, and upon replacing the solvent from\ntoluene to acetonitrile, the emission color changed from blue to yellow.