Amidophosphine−Phosphinites:  Synthesis and Use in Rhodium-Based Asymmetric Hydrogenation of Activated Keto Compounds. Crystal Structure of Bis[(μ-chloro)((S)-2-((diphenylphosphino)oxy)-2-phenyl-N-(diphenylphosphino)-N-methylacetamide)rhodium(I)]

Amidophosphine−phosphinite ligands (AMPP) derived from ( S )- N -benzylmandelamide (( S )-R,R‘-benzylmandelNOP ( S )- 1 (R = R‘ = phenyl) and ( S )- 7 (R = phenyl, R‘ = cyclopentyl)), ( S )- N -methylmandelamide (( S )-R,R‘-methylmandelNOP ( S )- 2 (R = R‘ = phenyl) and ( S )- 8 (R = phenyl, R‘ = cyclopentyl)), ( S )- N -methyllactamide (( S )-R,R‘-methyllactaNOP ( S )- 3 (R = R‘ = phenyl) and ( S )- 9 (R = phenyl, R‘ = cyclopentyl)), and ( S )-2-(hydroxymethyl)-2-pyrrolidinone (( S )-R,R‘-oxoProNOP ( S )- 4 − 6 and ( S )- 10 (R, R‘ = phenyl, cyclohexyl, cyclopentyl)) have been prepared in high yields (60−94%) and reacted with rhodium precursors to prepare neutral “Rh{AMPP}” complexes 11 − 26 of general formula [Rh{AMPP}X] 2, where X = Cl, I, OCOCH 3, OCOCF 3, and OCOC 3 F 7 . The crystal structure of [Rh{( S )-Ph,Ph-methylmandelNOP}Cl] 2 ( 12 ) has been determined. The rhodium atom has a cis square-planar coordination, and the seven-membered chelate ring has a boat conformation with the nitrogen atom in the mean plane RhP 2 . Complexes 11 − 26 have been used as catalyst precursors for the asymmetric hydrogenation of dihydro-4,4-dimethyl-2,3-furandione ( 27 ) and N -benzylbenzoylformamide ( 29 ) giving the corresponding optically active hydroxy compounds 28 and 30 in high yields and low to high enantiomeric excesses (28−98.7% ee and 13−87% ee, respectively). Catalytic activities (turnover frequency at 50% conversion at room temperature up to 3300 h - 1 ) as well as the enantioselectivities depended strongly on the nature of the substituents on phosphorus as well as on the nature of the non chiral ligands. Catalyst precursor [Rh{( S )-Cp,Cp-oxoProNOP}OCOCF 3 ] 2 afforded ( R )-pantolactone in 98.7% ee.