Binaphthyl-based chiral polymers

Bi-2-naphthols are among the most successful chiral ligands for several asymmetric catalysts. The synthesis of binaphthyl-based chiral polymers as rigid and sterically regular chiral polymers has recently been studied extensively [65-71]. Some recent devel-... 

The use of the binaphthyl-based chiral polymers in catalysis has been explored. We have demonstrated that incorporation of aluminum metal centers into the rigid binaphthyl polymer backbones leads to greatly enhanced catalytic activity over the monomeric aluminum complex. The catalytic activity of the polymeric aluminum and titanium complexes in the Mukaiyam aldol reaction has been studied. These polymeric metal complexes represent a new generation of polymer-based catalysts... 

Chiral l,l -Binaphthyl-Based Helical Polymers as Nonlinear Optical Materials... 

Binaphthyl molecules (chiral 2,2/-dihydroxy-l,T-binaphthyl) have been studied by Hicks et al., who reported the first experimental observation of CD-SHG on surfaces.4,29,43 In this section, we investigate the nonlinear optical properties of a chiral 1,1-binaphthyl-based helical polymer. 

Optically active l,l -binaphthols are among the most important chiral ligands of a variety of metal species. Binaphthol-aluminum complexes have been used as chiral Lewis acid catalysts. The l,T-binaphthyl-based chiral ligands owe their success in a variety of asymmetric reactions to the chiral cavity they create around the metal center [107,108]. In contrast with the wide use of these binaphthyls, the polymer-supported variety has been less popular. The optically active and sterically regular poly(l,l -bi-naphthyls) 96 have been prepared by nickel-catalyzed dehalogenating polycondensation of dibromide monomer 95 (Sch. 7) [109] and used to prepare the polybinaphthyl aluminum(III) catalyst 97 this had much greater catalytic activity than the corresponding monomeric catalyst when used in the Mukaiyama aldol reaction (Eq. 29). Unfortunately no enantioselectivity was observed in the aldol reaction. 

Optically active 1,1 -binaphthyl-based polymers incorporate chiral 1,17-binaphthyl units into the polymer backbone and possess stable main-chain... 

Scheme 21 Polymer-supported chiral binaphthyl-based Schrock catalysts.

A new chiral sub-unit to have been incorporated into crowns is the 2,2 -disubstituted-9,9 -spirobifluorene moiety (98). An electrochemical investigation, using ionophore-solvent-polymer membranes, of the enantiomer selectivity of a series of chiral neutral ionophores, including some crown ethers based on (98) or 2,2 -binaphthyl units, has been published.The best selectivity was shown by... 

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