Dendritic skeleton, synthesis

This diird route acconq>lished die synthesis of 2, which contains the fiill dendritic skeleton of Gadomer with a molecular weight of nearly 6000 Da, in only four synthetic steps and two chromatographic purification steps. The procedure was success y scaled up and 2 has been prepared in kilogram quantities in the pilot plant. 

The first synthesis of Gadomer was accomplished by the following steps [1] attachment of 14 onto the dendritic skeleton, [2] deprotection, and [3] con lexation. 

Recently, Soai et al. reported the synthesis of series of chiral dendrimer amino alcohol ligands based on PAMAM, hydrocarbon and carbosilane dendritic backbones (Figure 4.31) [99-102]. These chiral dendrimers were used as catalysts for the enantioselective addition of dialkylzincs to aldehydes and N-diphenylphosphi-nylimines (Scheme 4.25). The molecular structures of the dendrimer supports were shown to have a significant influence on the catalytic properties. The negative dendrimer effect for the PAMAM-bound catalysts was considered due to the fact that the nitrogen and oxygen atoms on the dendrimer skeleton could coordinate to zinc. 

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