Chiral templated synthesis of methylalumoxane and its catalytic properties in alkene oligomerization

Using optically active (R)-3-cyclohexenecarboxylic acid as a template in the reaction with (AlMe₃)₂, the stable adduct Me₂Al(µ-O-CMe₂C₆H₉)(µ-Me)AlMe₂ and methylaluminoxane (MAO) were synthesized. It is demonstrated that the activity of obtained MAO in the reaction of 1-hexene di- and oligomerization, catalyzed with zirconocenes (Cp₂ZrCl₂, Ind₂ZrCl₂, raс-EB[THI]ZrCl₂), is comparable with commercial MMAO-12. The use of chiral templated MAO in a catalytic system provides a significant change in the stereoselectivity of the reaction. Therefore, the stereoselectivity of the oligomerization process can be influenced by the activator structure, underscoring the importance of taking into account the activator counterion during the alkene insertion into the catalytically active sites.