The formation and reaction chemistry of ( η5-benzoylcyclopentadienyl)- and ( η5-carbomethoxycyclopentadienyl)( η4-tetraphenylcyclobutadiene)-cobalt

Article abstract of DOI:10.1016/0022-328X(96)06381-4

(η⁵-Benzoylcyclopentadienyl)η⁴-tetraphenylcyclobutadiene)cobalt, which has been synthesized from (η⁵-benzoylcyclopentadienyl)dicarbonylcobalt and 2 equivalents of diphenylacetylene, undergoes typical organic reactions, including reduction with sodium borohydride, reduction with lithium aluminum hydride/aluminum chloride, as well as the Wittig reaction. (η⁵-Carbomethoxycyclopentadienyl)(η⁴-tetraphenylcyclobutadiene)cobalt has also been prepared from (η⁵-carbomethoxycyclopentadienyl)dicarbonylcobalt and diphenylacetylene. The ester can be readily converted into the corresponding carboxylic acid, and sequentially into the acid chloride, amide, and cyano derivatives. The anhydride was prepared from the acid chloride. A Friedel-Crafts acylation reaction of (η⁵-chloroformylcyclopentadienyl)(η⁴-tetraphenylcyclobutadiene)cobalt, ferrocene and aluminum chloride in refluxing 1,2-dichloroethane has afforded a heterobimetallic ketone, (η⁵-ferrocenoylcyclopentadienyl)(η⁴-tetraphenylcyclobutadiene)cobalt.