Patrick L. Burk

Metallocycles as Intermediates in Organotransition-Metal Reactions

Metallocycles have been proposed as intermediates in a number of transition metal catalyzed reactions of organic compounds.1,2,3 In most cases it is difficult to distinguish between a non-concerted, stepwise reaction proceeding through a metallocyclic intermediate and a concerted “symmetry controlled” reaction.2,3,4,5 Consequently, stable tetramethylene metallocycles have been prepared and their structure and reactivities have been examined. These compounds should provide models for reactions which may involve metallocycles. Evidence for metallocycles in transition metal catalyzed olefin reactions, especially in the olefin metathesis reaction, has also been sought.