Patent ID: 6984744

Claim:
A phosphine compound of the formula I wherein R 1 and R 2 are independently of each other unsubstituted alkyl, aryl, cycloalkyl or heteroaryl, or alkyl, aryl, cycloalkyl or heteroaryl each of which independently is substituted by alkyl, alkoxy, halogen, hydroxy, amino, mono- or dialkylamino, aryl, —SO 2 —R 7 , —SO 3 − , —CO—NR 8 R 8′ , carboxy, alkoxycarbonyl, trialkylsilyl, diarylalkylsilyl, dialkylarylsilyl or triarylsilyl; R 3 is alkyl, cycloalkyl, aryl or heteroaryl; R 4′ and R 4 is independently of each other hydrogen, alkyl or optionally substituted aryl; or R 4′ and R 4 together, with the C-atom they are attached, form a 3-8-membered carbocyclic ring; dotted line is an optional double bond; R 5 and R 6 are independently of each other hydrogen, alkyl or aryl; R 7 is alkyl, aryl or NR 8 R 8′ ; and R 8 and R 8′ are independently of each other hydrogen, alkyl or aryl; the substituents R 3 on the phospholane phophorus atom and the substituent on the C2 atom of the phospholane ring are in cis relation to each other as indicated by the bold bonds in formula I.