Synthesis and structural analysis of a novel iodinated cyclopentadienone via ring-contraction iodination and its application in synthesis of alkyne-functionalized cyclopentadienones.

The first iodinated cyclopentadienone was isolated and its structure was confirmed by single crystal X-ray analysis. Based on this intermediate, the first direct C-C bond formation on cyclopentadienone ring was achieved. The photo induced intramolecular charge transfer of alkynylated cyclopentadienones was evaluated by solvent polarity effect on their electronic absorption spectra.

Investigation of sp(2)-sp coupling for electron-enriched aryl dihalides under oxygen-free Sonogashira coupling reaction conditions using a two-chamber reaction system.

Triethylamine hydroiodide crystals were formed during Sonogashira reactions; after complete reaction the solution retains a characteristic light color (see picture). Very sluggish Sonogashira reactions of electron-enriched aryl diiodides have been carried out in high yield in an oxygen-free, two-chamber reaction system. The formation of triethylamine hydroiodide crystals was monitored to determine the completion of reaction.