Spiro aminophosphine ligand

A novel class of complexes, Ir-(5 )-26a, with chiral spiro aminophosphine ligands was found to be effective catalyst for the asymmetric hydrogenation of a-substituted acrylic acids (Scheme 11) [62]. Under mild reaction conditions and at ambient pressure, various a-aryl and alkyl propionic acids were produced with extremely high efficiency (TONS up to 10 000 TOFs up to 6000h ) and excellent enantioselectivity (up to 99% ee). This reaction provides a practically useful method for the preparation of a-aryl propionic acids, a popular class of non-steroid anti-inflammtory reagents. 

The chiral iridium catalyst (258) bearing a tridentate spiro aminophosphine ligand catalysed the asymmetric hydrogenation of ketones in EtOH and KOBu with excellent enantioselectivities (up to 99.9% ee) and extremely high turnover numbers. ... 

J-B Xie, J-H Xie, X-Y Liu, W-L Kong, S Li, Q-L Zhou. Highly enantioselective hydrogenation of a-arylmethylene cycloalkanones catalyzed hy iridium complexes of chiral spiro aminophosphine ligands. J. Am. Chem. Soc. 2010 132 (13) 4538 539. 

Chiral transition-metal complexes have also been featured in the following reports " of asymmetric carbonyl reductions hydrogenation of / -aryl- -ketoesters 0 using H2 and iridium-bearing spiro pyridine-aminophosphine ligand rhodium in a theoretical study of catalysis involving amino acid-derived ligands and in... 

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