PS supported BINAP

Two PEG-PS supported BINAP ligands have been prepared by reaction of a suitably derivitized support and dihydroxy BINAP 112 (Scheme 53). Starting from acid-functionalized support 111, 112 was attached to form 113. A ligand loading of 0.1 mmol g was obtained. Starting from bromo-functionalized support 114, supported BINAP 115 was made by first treating 112 with BuLi before adding the resin. 

The PEG-PS supported BINAPs 113 and 115 were used as ligands for Rh-catalyzed asymmetric isomerizations, the metal complexes being formed in situ by reaction of the supported ligands with [Rh(cod)2] [CF3S03]. Both these and their silica-immobilized counterparts were found to be less reactive than their homogenous analogs... 

The PS-PEG resin-supported BINAP ligand was prepared and used successfully for the rhodium-catalyzed asymmehic 1,4-addihon reachon in water [29]. BINAP bearing a carboxyhc group at the 6-posihon was immobihzed by an amide bond on an amphiphihc PS-PEG NH2 resin (Scheme 6.7). The PS-PEG BINAP 59 was heated with Rh(acac)(G2H4)2 to form the PS-PEG-BlNAP-Rh complex. The polymeric BINAP-Rh complex showed high catalyhc achvity and high enanhoselectivity in water for the 1,4-addihon of phenylboronic acid to a,P-unsaturated ketones (Scheme 6.8). 

An alternative approach to a PS-PEG amphiphilic BINAP has been reported involving reaction of BINAP-carboxylic acid 116 with an amine-functionalized PEG-PS support to give 117 (Scheme 54). ... 

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