Poly propellane

Schemed Examples for the convergently executed route A using poly([l.l.l]propellane) (a) and poly(para-phenylene) backbones (b, c)... 

Two rings linked by sharing the same bond instead of the same atom lead to annulated bicyclic or tricyclic compounds, the propellanes. In the case of poly-unsaturated molecules, an interesting case is represented by the bicyclo[2.2.0] type. The parent compound Dewar benzene (bicyclo[2.2.0]hexa-2,5-diene) (DEW) is the smallest bicyclic diene which is an often discussed valence isomer of aromatic benzene Unsubstituted DEW is a very... 

The second method involves substitution reactions on a preformed polymer with a stiff backbone. The advantage of this method is that it provides better control over the MW of the starting polymer. However, the substitution may not be 100%. The first example involved the substitution on a poly( 1,1,1-propellane) copolymer [116]. A copolymer with 80% functionalizable units has been successfully modified with a [G-1]-Br poly(benzyl ether) dendron (see Scheme 13a). Further studies exploring the feasibility and steric limitations of the substitution route have been performed on poly(p-phenylene) [113, 116]. The Williamson substitution reaction on... 

Schliiter et alJ65,66 have recently used rod-shaped polymers1673 such as poly(p-phe-nylene)s and poly([l.l.l]propellane)s as cores for the attachment of convergently generated dendrons. These new branched macromolecules possess a rigid backbone wrapped with structural wedges, which become increasingly more dense toward the outer cylindrical surface. The Pd-catalyzed copolymerization of dibromobiphenyl derivatives with the Frechet-type ethereal dendrons with a substituted aryl diboronic acid afforded the dendritic coated poly(p-phenylene) rod. 

An alternative approach developed by Schluter and co-workers involves the attachment of convergently prepared dendrons onto a preformed, functional linear polymer. This was first attempted by the Williamson ether couplings between dendritic bromides and pendant hydroxyl groups on poly([ 1.1.1]-propellane)412 and polyp-phenylene).413 Nearly quan-... 

Rings s. a. Adamantanes, Alcohols, cyclic, Hetero-cyclics, Isocyclics, Ketones, cyclic, Macrocyclics, Poly-cyclics, Propellanes -, condensed highly condensed s. Cage compds. 

Instead of anchoring dendrons at the end of the linear chains, Schluter and his co-workers [52] attached Frechet-type dendrons onto the rodlike, rigid backbone of poly([l,l,l]-propellane)s and polyphenylenes on which hydroxy functionalities had previously been generated. Schluter s group made use of... 

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