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.
KeywordsNickel Lithium Tungsten Molybdenum Anhydride
Unable to display preview. Download preview PDF.
- 2.L. Cassar, P. E. Eaton and J, Halpern, J. Am. Chem. Soc., 92, 3515 (1970)Google Scholar
- 3.T. Katz and S. Cerefice, J. Am. Chem. Soc., 91, 6520 (1969).Google Scholar
- 5.G. S. Lewandos and R. Pettit, Tetrahedron Lett., 780 (1971).Google Scholar
- 10.N. Calderon, Accounts Chem. Res., 5, 127 (1972).Google Scholar
- 12.The optimum metathesis rate is obtained when the W/RLi ratio (for octyl lithium) is 2.Google Scholar
- 13.Under similar conditions, a 1:1 mixture of 1,2-dideuteroethylene, ethylene has changed to a 1:2:1 mixture of 1,2-dideuteroethylene, deuteroethylene and ethylene.Google Scholar
- 14.We acknowledge the support of the Petroleum Research Fund administered by the American Chemical Society for this research.Google Scholar