Metal-Free Oxidative Radical Alkynylation/Ring Expansion Rearrangement of Alkenyl Cyclobutanols with Ethynylbenziodoxolones.

The first metal-free alkynylation/ring expansion cascade process of alkenyl cyclobutanols with ethynylbenziodoxolones has been developed. A variety of synthetically valuable ß-alkynylated cyclopentanones were prepared in moderate to good yields. Alkynyl cyclobutanols could also undergo this transformation, providing a new approach to substituted ene-yne-carbonyl compounds.

Cobalt(III)-catalyzed alkenylation of arenes and 6-arylpurines with terminal alkynes: efficient access to functional dyes.

Alkenylation of unactivated arenes and 6-arylpurines with terminal alkynes in high yields using Cp*Co(CO)I2 as catalyst under mild conditions is described. This method shows outstanding functional group compatibility and can be applied in the design of a mitochondria-targeted imaging dye.