AMIDOPHOSPHINE-PHOSPHINITES - SYNTHESIS AND USE IN RHODIUM-BASED ASYMMETRIC HYDROGENATION OF ACTIVATED KETO COMPOUNDS - CRYSTAL-STRUCTURE OF -(DIPHENYLPHOSPHINO)-N-METHYLACETAMIDE)RHODIUM(I)]

Amidophosphine-phosphinite ligands (AMPP) derived from (S)-N-benzylman delamide ((S)-R,R'-benzylmandelNOP (S)-1 (R = R' = phenyl) and (S)-7 ( R = phenyl, R' = cyclopentyl)), (S)-N-methylmandelamide ((S)-R,R'-meth ylmandelNOP (S)-2 (R = R' = phenyl) and (S)-8 (R = phenyl, R' = cyclop entyl)), (S)-N-methyllactamide ((S)-R,R'-methyllactaNOP (S)-3 (R = R' = phenyl) and (S)-9 (R = phenyl, R' = cyclopentyl)), and (S)-2-(hydrox ymethyl)-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 = C l, I, OCOCH3, OCOCF3, and OCOC3F7. 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 r ing has a boat conformation with the nitrogen atom in the mean plane R hP2. Complexes 11-26 have been used as catalyst precursors for the asy mmetric hydrogenation of dihydro-4,4-dimethyl-2,3-furandione (27) and N-benzylbenzoylformamide (29) giving the corresponding optically activ e hydroxy compounds 28 and 30 in high yields and low to high enantiome ric excesses (28-98.7% ee and 13-87% ee, respectively). Catalytic acti vities (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} OCOCF3](2) afforded (R)-pantolactone in 98.7% ee.