Asymmetric alkylmethyl zirconocene derivatives were readily synthesised from Cp(2)ZrCl(CH(3)), and the appropriate alkyllithium reagent. The alkyl groups contain a silyl functionality on the beta-position. These asymmetric dialkyl zirconocenes were successfully activated by B(C(6)F(5))(3), selectively abstracting the methyl group. The clear difference in the (13)C NMR resonances, due to the alkyl groups on the cationic zirconocene made it possible to conclude that selective activation of this class of compounds was possible. (C) 2010 Elsevier B. V. All rights reserved.
Chloromethylsilane functionalised dendrimers: synthesis and reactivity
摘要:
Tetraallylsilane was functionalised using (chloromethyl)dimethylsilane to give the first generation chloromethyl terminated dendrimer 1. The resulting dendrimer was successfully reacted with K[CpM(CO)(2)] (Cp = eta(5)-C5H5; M = Fe, Ru) to give Si[(CH2)(3)SiMe2CH2MCp(CO)(2)](4) functionalised dendrimers in satisfactory yield. Reaction of dendrimer 1 with NaI in acetone gave the -SiMe2CH2I functionalised dendrimer, while reactions of 1 with K[CpM(CO)(3)] (M = Mo, W, Re), Li[C5Me4H], Na[C5Me4H], the cobaloxime nucleophile or tert-BuLi were not successful. (C) 2004 Elsevier B.V. All rights reserved.