III International Conference

PP-II-46Cycloalumination of 1,7-octadiene with EtAlCl 2 (two-fold excess) under the reactionconditions (Cp 2 ZrCl 2 (10 mol %), THF, 20 o C, 8 h) resulted in 1-ethyl-3,4-di(hex-5-enyl)aluminacyclopentane and cyclododecane with two symmetrically annulatedaluminacyclopentane fragments.Unlike 1,5-hexadiene and 1,7-octadiene, 1,9-decadiene and 1,11-dodecadiene come intothe cycloalumination reaction with EtAlCl 2 catalyzed by Cp 2 ZrCl 2 to produce selectivelytrans-3,4-disubstituted aluminacyclopentanes in ~ 40–45 % yield.+ EtAlCl 2+ Mg[Zr]-MgCl 2EtAlAlEtAlEt+EtAl(1) (2) (3)AlEt+AlEtWhile proceeding the cycloalumination reaction of α,ω-diolefins with EtAlCl 2 in thepresence of Cp 2 ZrCl 2 minor amounts of the hydroalumination and aluminacyclopropanationproducts (5–18 %) were detected as well.It was shown that under the effect of stoichiometric amounts of allylchloride and Pdcontainingcatalysts generated in situ cyclic OAC transform into cyclobutanes. Demetallationof cyclic OAC by elemental sulfur was found to yield the related polycyclic thiophanes.The probable cycloalumination mechanism for α,ω-diolefins under the effect of catalyticamounts of Cp 2 ZrCl 2 is discussed. The generation of zirconacyclopentane intermediates withsubsequent transmetallation by EtAlCl 2 to give the related cyclic OAC is proposed as the keystep of the reactions involved.The research work was financially supported by grants of RF President (NSh-7470.2006.3) and the Russian Foundation for Basic Research (Project No. 05-03-32367).Reference1. U.M. Dzhemilev, A.G. Ibragimov, A.B. Morozov, R.R. Muslukhov, G.A. Tolstikov. Izv. ANSSSR. Ser. Khim., 1991, P. 1607.248