Dendrimers polycarbosilanes

In order to avoid this unfavourable effect of the functional groups in the dendrimer structure, a rigid hydrocarbon backbone without heteroatoms was synthesized. Dendrimers with poly(phenylethyne) backbones, bearing three and six ephedrine derivatives at the periphery, were studied in the alkylation of aldehydes and N-diphenylphosphinylimines and proved to be highly en-antioselective catalysts. For example, the system containing six catalytic sites catalyzed the addition of diisopropylzinc to aldehydes with enantioselectivi-ties of up to 86% ee. As a third backbone a polycarbosilane dendrimer was used, which is chemically inert and more flexible than the poly(phenylethyne)... 

Chai et al employed triple-resonance H/ C/ Si 3D-NMR methods to unambiguously assign the resonances in Cl (90) and G2 polycarbosilane dendrimers (91), using signals from one-bond and two-bond connectives among atoms coupled to C and Si. 

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