Tethered 2+2+2 cycloaddition reactions of cobalt-cycloheptyne complexes
Cycloheptyne-dicobalt hexacarbonyl complexes, substituted by propargylic ether functions, undergo 2+2+2 cycloaddition reactions with alkynes to give tricyclic benzocycloheptanes; an all-intramolecular version of this transformation is also possible.
Mohamed, A. B. and Green, James R.. (2003). Tethered 2+2+2 cycloaddition reactions of cobalt-cycloheptyne complexes. Chemical Communications (23).