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Chiral aryl dendrimer

Fig. 4.62 Chiral-core dendrimers of various generations (according to Seebach et al.), consisting of a chiral tris(hydroxymethyl) methane core unit and poly (aryl ether) dendrons (GO, Gl, or G2), which are linked to the core either directly (A), via an aliphatic spacer (B), or via an aromatic spacer (C)... Fig. 4.62 Chiral-core dendrimers of various generations (according to Seebach et al.), consisting of a chiral tris(hydroxymethyl) methane core unit and poly (aryl ether) dendrons (GO, Gl, or G2), which are linked to the core either directly (A), via an aliphatic spacer (B), or via an aromatic spacer (C)...
To investigate the effect of chirality in dendrimers, a number of groups have incorporated chiral spacers into the poly(aryl ether) repeat unit. Chow et al.96-100 modified their dihydroxyphenoxypropanol repeat unit 27 to include the acetonide protected diol spacers (2R,3R) or (25,35)-threitol, 28 and 29. McGrath and co-workers incorporated similar chiral protected diols 30-33 into their studies,101-105 whereas Seebach and co-workers106-109 investigated the di- and tribranched chiral monomers 34-36. [Pg.60]

Chiral dendrimers based on oligonaphthyl cores and Fr chet-type poly(aryl ether) dendrons have been investigated [44]. The absolute configuration of these dendrimers remains the same as that of their chiral cores. Both the nature of the core and the generation play a role in determining the fluorescence quantum yield. [Pg.170]

In 2008, these authors reported a new strategy to attach chiral trans-l-arenesulfonylamino-2-isoborneolsulfonylaminocyclohexane to an achiral Frechet dendron (polyether having a repeated 3,5-dioxybenzyl structure) by a radical approach.The dendrimers obtained were successfully used in the enantioselective nucleophilic alkylation and arylation of ketones, providing... [Pg.177]

Sharpless et al.l20b have constructed chiral dendrimers by employing the doubleexponential synthetic method.[20c] Chirality was induced via the use of aryl acetonide monomers prepared by asymmetric dihydroxylation (AD) of the corresponding prochiral alkenes. Each monomeric unit possessed two asymmetric carbons. Examples described are C3-symmetric and contain up to 45 chiral building blocks with 24 acetonide termini. [Pg.185]

Dendrimers including a chiral part, carried by either the central core or the branching points distributed in the dendritic structure, have attracted recent interest. Three research groups ventured into this area, but the main contribution was due to Seebach s team [32]. These researchers relied on Frechet s synthetic approach to first make aryl ether dendrons and then attach them to various chiral cores having either a true chiral center (Scheme 9A) or unsym-... [Pg.254]


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See also in sourсe #XX -- [ Pg.187 ]




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