CATALYTIC SYNTHESIS AND REACTIONS OF MAGNESIOCYCLOALKANES .2. SYNTHESIS OF SUBSTITUTED MAGNESIOCYCLOPENTANES IN THE PRESENCE OF ZIRCONIUM COMPLEXES

Catalytic cyclometallation of styrene, m-methylstyrene, p-tert-butylstyrene, and 1-hexene with di-n-alkylmagnesium compounds (n-R2Mg, where R = C3H7, C4H9, and C6H13) in the presence of Cp2Zr2Cl2 has given high yields of 2,4-disubstituted magnesiocyclopentanes. The probable mode of formation of magnesiocyclopentanes, involving zirconocyclopentanes formed from Cp2ZrCl2, n-R2Mg, and the appropriate olefins as reactive intermediates in the cyclometallation, is discussed.