Highly enantioselective hydrogenation of alpha-dehydroamino esters and itaconates with triphosphorous bidentate ligands and the unprecedented solvent effect thereof.
An X-ray diffraction experiment revealed an interesting triphosphorous bidentate coordination in a Pd(II) complex of a phosphine-phosphoramidite ligand 1, which showed excellent enantioselectivity (up to 99.4% ee) in Rh-catalyzed hydrogenation of alpha-dehydroamino esters in acetone. A dramatic solvent effect was found in the hydrogenation of itaconates, which induces opposite chiralities of the product with the same catalytic system by the use of different solvents (e.g., 99.6% ee (R) in TFE vs 71.2% ee (S) in methyl ethyl ketone).
Zhang
Weicheng
W
Department of Chemistry, 104 Chemistry Building, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Zhang
Xumu
X
D002074:Butanones / Q000737:chemistry; D002384:Catalysis; D004952:Esters / Q000737:chemistry*; D006865:Hydrogenation; D008024:Ligands; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry; D009943:Organophosphorus Compounds / Q000737:chemistry; D010165:Palladium / Q000737:chemistry; D010720:Phosphines / Q000737:chemistry; D011138:Polytetrafluoroethylene / Q000737:chemistry; D012997:Solvents / Q000737:chemistry*; D013237:Stereoisomerism; D013386:Succinates / Q000737:chemistry*; D014961:X-Ray Diffraction
D002074:Butanones; D004952:Esters; D008024:Ligands; D009942:Organometallic Compounds; D009943:Organophosphorus Compounds; D010720:Phosphines; D012997:Solvents; D013386:Succinates; C434331:phosphoramidite; D010165:Palladium; C005222:methylethyl ketone; D011138:Polytetrafluoroethylene; C044646:phosphine; C005229:itaconic acid