Mixed disilyl-substituted cyclopentadiene derivatives and corresponding zirconium, molybdenum and tungsten compounds

The mixed disilyl-substituted cyclopentadiene C5H 4[Si-Me2(CH=CHCH3)](SiMe3) (2) has been synthesized in a onepot reaction by alkylation, deprotonation and silylation of C5H5(SiMe2Cl). The analogous olefin-tethered cyclopentadiene C5H4[SiMe 2(CH2CH=CH2)](SiMe3) (3) has been obtained through traditional metathesis routes from Li[C5H 4-(SiMe3)] and the chloroallylsilane SiMe 2(CH2CH=CH2)Cl. The corresponding mixed disilyl-substituted cyclopentadienyllithium salts Li[C5H 3-1-SiMe2R-3-SiMe3] [R = CH=CHCH3 (cis+trans-4); R = CH2CH=CH2 (5)] were used to isolate the chiral zirconium compounds [ZrX(η5-C5H 4SiMe2-η1-NtBu)-(η5-C 5H3-1-SiMe2R-3-SiMe3)] [X = Cl, R = CH=CHCH3 (cis+trans-6); R = CH2CH=CH2 (7); X = CH3, R = CH=CHCH3 (cis+trans-8); R = CH 2CH=CH2 (9)] and group 6 derivatives [MH(η 5-C5H3-1-SiMe2R-3-SiMe 3)(CO)3] [R = CH=CHCH3, M = Mo (cis+trans-10), M = W (cis+trans-11); R = CH2CH=CH2, M=Mo (12) and M = W (13)], which have been fully characterized. The behaviour of metal compounds 8-13 has been studied and compared with that previously reported for monosubstituted alkene-silylcyclopentadienyl systems [Zr(CH3)- (η5-C5H4SiMe2-η1- NtBu)[(η5-C5H4SiMe2)(CH 2CH=CH2)] and [MH(η5-C5H 4SiMe2-η1-NtBu)[(η5-C 5H4SiMe2)(CH2CH=CH2)] (M = Mo, W). © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.