Ortho Lithiation of Tetrahydroquinoline Derivatives and Its Use for the Facile Construction of Polymerization Catalysts

Ortho lithiation is achieved by the treatment of tBuLi to the lithium carbamate compounds derived from 2-R-1,2,3,4-tetrahydroquinolines (R = H, methyl, n -butyl, tert -butyl, and 6- tert -butoxyhexyl), which enables the facile construction of the o -phenylene-bridged (Me 4 C 5, indenyl, or fluorenyl)/amido titanium complexes. The titanium complex derived from 2-methyltetrahydroquinoline exhibits higher activity, higher 1-octene incorporation, and higher molecular weight in ethylene/1-octene copolymerization than the standard CGC, [Me 2 Si(η 5 -Me 4 C 5 )(N t Bu)]TiCl 2 .