Organometallic Derivatives of Cycloproparenes

The tricarbonylchromium complex of cyclopropab]naphthalene ( 3a ) is deprotonated at C(1) with BuLi. Quenching of the resulting anion with Mel results in a 1:1 mixture of stereoisomeric methyl derivatives 6a and 6b . Peterson olefination of the bis-silylated complex 3b affords the complexed alkylidenecycloproparene 5 in low yield. The tricarbonylchromium complex of cyclopropab]anthracene ( 10 ) is accessible via bis-hydro-desilylation of 9 . Its X-ray structure is also reported. All attempts to synthesize a tricarbonylchromium complex of benzocyclopropene ( 11a ) failed.