| abstract |
The invention is concerned with new phosphine ligands of the formula (I) wherein R1 and R2 are independently of each other alkyl, aryl, cycloalkyl or heteroaryl, said alkyl, aryl, cycloalkyl or heteroaryl may be substituted by alkyl, alkoxy, halogen, hydroxy, amino, mono- or dialkylamino, aryl, -SO2-R7, -SΟ3¯, -CO-NR8R8’, carboxy, alkoxycarbonyl, trialkylsilyl, diarylalkylsilyl, dialkylarylsilyl or triarylsilyl; R3 is alkyl, cycloalkyl, aryl or heteroaryl; R4’ and R4 signify independently of each other hydrogen, alkyl or optionally substituted aryl; or R4’ and R4 together with the C-atom they are attached to form a 3-8-membered carbocyclic ring; dotted line is absent or is present and forms a double bond; R5 and R6 are independently of each other hydrogen, alkyl or aryl; or linked together to form a 3-8-membered carbocyclic ring or an aromatic ring; R7 is alkyl, aryl or NR8R8’; and R8 and R8’ are independently of each other hydrogen, alkyl or aryl; metal complexes with such ligands as well as the use of such metal complexes as catalysts in asymmetric reactions. |