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

The ortho-lithiation of N-alkylanilines is accomplished by the treatment of tBuLi 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 Me4C5, indenyl, or fluorenyl unit at an ortho-position. From the compounds, various o-phenylene-bridged (Me4C5, indenyl, or fluorenyl)/amido titanium complexes are prepared in one step. The Me4C5/ethylamido titanium complex exhibits a similar catalytic performance to the CGC [Me2Si(η5-Me4C5)(NtBu)]TiCl2 in ethylene/1-octene copolymerization in terms of activity, molecular weight of the obtained polymer, and 1-octene incorporation.