Hydrogenation chiral hgands, asymmetric

The influence of the concentration of hydrogen in [BMIM][PFg] and [BMIMKBF4] on the asymmetric hydrogenation of a-acetamidociimamic add catalyzed by rhodium complexes bearing a chiral Hgand has been investigated. Hydrogen was found to be four times more soluble in the [BFJ-based salt than in the [PFg] -based one. 

Revision. This phosphine oxide is used in the synthesis of DIPAMP, the chiral hgand for asymmetric catalytic hydrogenation mentioned in the chapter. What are the various reagents doing in the conversion into DIPAMP ... 

The invention of efficient chiral phosphorous ligands has played a critical role in the development of asymmetric hydrogenation. To a certain extent, the development of asymmetric hydrogenation parallels that of chiral phosphorous hgands. 

Recently, many effective chiral bisphosphane hgands with a ferrocene backbone have been developed (Scheme 1.4). Ito has successfully developed a series of traits-chelating bisphosphane hgands, TRAPs, which are highly selective for rhodium-catalyzed asymmetric hydrogenation [46]. 

The diversity requirement of chiral amines in the synthesis of natural products and chiral drugs is everlasting and the most studies about the catalytic asymmetric hydrogenation of enamines have dealt with simple substrates to date. Hence, it is necessary to explore highly efficient enantioselective protocol to provide more complex and also industrially useful chiral amines. We are confident that the easily accessible and changeable monodentate phosphorus hgands will find a wide appli cation in this field. 

In the Rh catalyzed asymmetric hydrogenation of enamides, why can the mixed two different chiral monodentate phosphorus hgands improve the enantioselectivity of reaction in some cases ... 

In recent years an amazing number and variety of chiral ferrocene ligands have been used in asymmetric catalysis. A quite remarkable example of the great utility of chiral ferrocene hgands is the synthesis of a precursor of the herbicide (IX)-metolachlor by an Ir-Xyliphos-catalysed asymmetric imine hydrogenation reaction (Scheme 3.19). 

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