CO₂-Mediated ortho-Lithiation of N-Alkylanilines and Its Use for the Construction of Polymerization Catalysts

The ortho -lithiation of N -alkylanilines is accomplished by the treatment of t BuLi with the lithium carbamate compounds generated in situ from N -alkylanilines. The lithiated compounds attack the carbonyl-carbon on 2,3,4,5-tetramethylcyclopentenone, 1-indanone, or 9-fluorenone to yield tertiary alcohols, which are transformed to N -alkylanilines attaching a Me 4 C 5, indenyl, or fluorenyl unit at an ortho -position. From the compounds, various o -phenylene-bridged (Me 4 C 5, indenyl, or fluorenyl)/amido titanium complexes are prepared in one step. The Me 4 C 5 /ethylamido titanium complex exhibits a similar catalytic performance to the CGC [Me 2 Si(η 5 -Me 4 C 5 )(N t Bu)]TiCl 2 in ethylene/1-octene copolymerization in terms of activity, molecular weight of the obtained polymer, and 1-octene incorporation.