Oligomerisation and Stereoselective Polymerisation of Alkenes and Alkynes Using Pyridyl-based Al(III) Catalysts

Abstract

Dealkylation of the dimers [R2Al(2-py')]2 (2-py’ = 6-substituted pyridyl, R = Me, iBu) with [Ph₃/sub>C][B(C6F₅)₄] gives the putativecations [RAl(₂-py')₂(μ-R)AlR]⁺ which can polymerise a range of alkenes with a high degree of stereo-regularity (syndiotacticity in the case of polystyrene) and cylotrimerise terminal alkynes to tri-substituted benzenes and a fulvene. This is the first report of stereoselective Al(III) polymerisation and of the cyclotrimerisation of alkynes by static catalysis using a main group metal.