Phosphine-phosphoramidite ligands

Figure 9.10 Chiral ferrocene based phosphine phosphoramidite ligands (PPFAPhos) developed within our group.

Figure 9.12 Other phosphine phosphoramidite ligands for asymmetric hydrogenation.

Scheme 9.11 Rh catalyzed asymmetric hydrogenation of ortho substituted arylenamides with a triphosphorus bidentate phosphine phosphoramidite ligand 49.

Leitner and coworkers disclosed new phosphine phosphoramidite ligands con taining two elements of chirality, which can be prepared via a modular approach. These ligands proved to be very efficient for asymmetry of 2 substituted quino lines [22]. The hydrogenation reaction proceeded smoothly with up to 97% ee and full conversion (Scheme 10.16). 

Progress on unsymmetrical hybrid chiral phosphine—phosphoramidite ligands and their application in asymmetric catalytic reactions 12CJ02239. Rare earth metal oxazoline complexes in asymmetric catalysis 12CC 10587. 

Wassenaar and Reek [28] prepared four chiral phosphine-phosphoramidite ligands called INDOLPhos and tested them in the hydroformylation of styrene (Scheme 2.129). In the best case, a b/l ratio of 10 and enantioselectivity of 72% were observed. 

As with other P(III) compounds, the binaphthol (BINOL) derivatives have been by far the most successful for a wide range of synthetic methods. Several reviews and reports have been published on the incorporation of BINOL-derived phosphoramidites in rhodium-catalysed asymmetric hydrogenations Novel chiral phosphine-phosphoramidite ligands, HY-Phos (61) and THNAPhos (62), have also been successful in rhodium-catalysed asymmetric hydrogenations. Asymmetric synthesis of the Roche ester and its derivatives (63) by rhodium-INDOLPHOS-catalysed hydrogenation was reported and a number of other BINOL-derivered phosphoramidates have been employed in iridium-catalysed hydrogenations and allylic alkyla-... 

Zhang W, Zhang X. Synthesis of triphosphorous bidentate phosphine-phosphoramidite ligands application in the highly enantioselective hydrogenation of ort/io-substituted aryl enamides. Angew. Chem. Int. Ed. 2006 45(33) 5515-5518. 

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