Reactions of 1,8‐Diheterocyclotetradeca‐4,11‐diynes

The following monocyclic and bicyclic 14‐membered diynes were treated with [ CpCo(cod)]: 1‐oxacyclotetradeca‐4,11‐diyne, 1,8‐dioxacyclotetradeca‐4,11‐diyne, cyclotetradeca‐4,11‐diynone, cyclotetradeca‐4,11‐diyne‐1,8‐dione, 1,1,8,8‐tetramethyl‐1,8‐disilacyclotetradeca‐4,11‐diyne, 1‐allyl‐1‐azacyclotetradeca‐4,11diyne, 1,8‐dipropyl‐1,8‐diazacyclotetradeca‐1,11‐diyne, 1,8‐diallyl‐1,8‐diazacyclotetradeca‐4,11‐diyne, 1,8‐diazabicyclo[ 6.6.4]octadeca‐4,11‐diyne, 1,8‐diazabicyclo[ 6.6.6]eicosa‐4,11‐diyne, 1,10‐diazabicyclo[ 8.6.6]docosa‐13,19‐diyne and 1,12‐diazabicyclo[ 10.6.6]tetracosa‐15,21‐diyne. In all cases we obtained an intramolecular cyclobutadiene complex stabilized with a CpCo fragment. For 3 we could isolate, besides the cyclobutadiene complex 16, the trimerization product. In the certain cases the structure of the cylobutadiene complexes could be confirmed by X‐ray studies. Common to all structures is a boat‐like conformation of the tricyclic unit containing the cyclobutadiene ring. The two cycloheptene units adopt a chair conformation in which the heteroatom is removed from the metal center.