Chiral ferrocenyldiphosphine ligand

Togni and his co-workers prepared dendrimers containing chiral ferrocenyldiphosphines and investigated the palladium-catalyzed allylic alkylation using these phosphines as chiral ligands to obtain the corresponding allylic alkylated compounds with a high enantioselectivity (up to 91% On the other hand, Malmstrom and his... 

Phenols are used as the nucleophile in the asymmetric aUylation of 7r-aUylpalladium complexes. Trost and Toste attained asymmetric phenyl ether formation in high enantiomeric excess (ee) using diphosphine ligand derived from chiral 1,2-cyclohexanediamine (equation 10). Dynamic kinetic resolution of the racemic secondary aUylic carbonate is conducted in the presence of tetrabutylammonium chloride, which increases the rate of ft—a—ft isomerization of the jr-allyl palladium intermediate (equation 11). Lautens and coworkers cleaved meio-oxabicyclic alkenes with phenol in the presence of a catalytic amount of a chiral ferrocenyldiphosphine and a rhodium complex (equation 12). ... 

Togni et al.169 synthesized dendrimers using a cyclophosphazene core and 16 peripheral chiral ferrocenyl ligands (Figure 10.13). The periphery of these ferrocenyldiphosphine metallo-dendrimers was decorated with [Rh(COD)2][BF4] to instill the desired catalytic properties necessary to reduce dimethyl itaconate. These metalloconstructs showed 98% ee, which compared well with the 99% ee obtained with monomeric Rh-based josiphos catalyst. 

The ferrocenyldiphosphine ligand 99 constitutes a catalytic system with (cod)2RhBp4 for synthesizing a-alkylsuccinic acid derivatives from the alkylidene compounds. Secondary acetates in chiral form are accessible from hydrogenation of enol acetates using the catalytic system of (cod)2RhBF4-100. ... 

The synthesis and application of chiral ferrocene derivatives has attracted much interest.358 Hence the ferrocenyldiphosphine (163) (Josiphos) can be prepared by direct HPR2 substitution of the dimethylamino group (Equation (40)).359 Various other ferrocene-based chiral ligands are known (e.g., the TRAP ligands (164)).360-364... 

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