Room-Temperature <i>Z</i>-Selective Homocoupling of α-Olefins by Tungsten Catalysts

3,5-Dimethylphenylimido complexes of tungsten can be prepared using procedures analogous to those employed for other tungsten catalysts, as can bispyrrolide species and MonoAryloxide-Pyrrolide (MAP) species. Homocouplings of 1-hexene, 1-octene, and methyl 10-undecenoate are achieved in 45−89% yield and a Z selectivity of >99% with W(NAr′′)(C3H6)(pyr)(OHIPT) as a catalyst. Homocoupling of terminal olefins in the presence of (E)-olefins elsewhere in the molecule also was achieved with excellent selectivity.