In this study, insertion reaction of 10-undecen-1-ol (Un-OH) into the metallocene active center was investigated in the absence of olefin monomers. 10-Undecen-1-ol protected with trialkylaluminum (Un-O-AlR2,; R=Me, Et, n-Bu, i-Bu) was treated with an En(Ind)(2)ZrCl2/MAO catalyst system. The reactant, after quenched with HCl, was analyzed to identify the resulting alcohol compounds by gas chromatography with the comparison of authentic samples and NMR methods. As a result, undecanol (saturated Un-OH) and other alcohol compounds, in which alkyl groups derived from trialkylaluminum were incorporated into Un-OH, were found mainly in the resulting compounds, supporting that Un-O-AlR2, was inserted into the metallocene active center in the absence of olefin monomers. The mechanism of the insertion reaction of Un-O-AlR2 was also discussed. (c) 2005 Elsevier B.V. All rights reserved.