Transannular [4 + 2] Cycloaddition Reactions of Cobalt-Complexed Macrocyclic Dienynes.
- Author(s): Karabiyikoglu, Sedef
- Merlic, Craig A
- et al.
Published Web Locationhttps://doi.org/10.1021/acs.orglett.5b01984
The first transannular [4 + 2] cycloaddition reactions of macrocyclic dicobalt hexacarbonyl-dienyne complexes were demonstrated. Complexes were conveniently prepared through palladium(II)-catalyzed intramolecular oxidative cyclization of bis(vinylboronate esters) followed by complexation with dicobalt octacarbonyl. Transannular [4 + 2] cycloaddition reactions of the complexes occurred at lower temperatures and shorter times than transannular Diels-Alder reactions of metal-free dienynes. Intermolecular control reactions confirmed the effect of cobalt complexation on [4 + 2] cycloaddition reactions of unactivated alkynes and dienes.