Chiral N, P Ligands

The development of Ir-chiral N,P ligand system opens another promising way for the hydrogenation of allylic alcohol and its derivatives. For example, a cationic Phox-Ir complex catalyzes the hydrogenation of ( )-2-methyl-3-phenyl-9-propen-l-ol in a highly enantioselective fashion.178 With 1 mol.% (5)-92-Ir catalyst, the hydrogenation proceeds completely to provide the chiral alcohol product in 96% ee. Under the same conditions, a para- Bu-substituted chiral alcohol derivative is obtained with 94% ee for the synthesis of lilial (Equation (59)). Heterocyclic N, P-ligand, HetPHOX 113, is also efficient for this reaction.191... 

Chiral monophosphorus ligands, in hydrogenation, 10, 16 Chiral nematic phase, calamitic mesogens, 12, 200 Chiral N,P ligands, in hydrogenation, 10, 17 Chiral phosphines... 

In addition. Taller and Chase have reported the use of chiral tridentate S/N/P ligands for the rhodium-catalysed hydrosilylation of ketones.The best ligand, which provided an enantioselectivity of up to 64% ee, was that bearing the shortest reach to the metal to give a tridentate ligand, as shown in Scheme 10.51. 

Iridium-Catalyzed Asymmetric Hydrogenation of Olefins with Chiral N,P and C,N Ligands 33... 

Iridium-Catalyzed Asymmetric Hydrogenation of Olefins with Chiral N,P and C,N Ligands 55 Table 4 Asymmetric hydrogenation of a-substltuted a,(3-unsaturated amides with ligand 24... 

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