| abstract |
From 2,2 ', 6,6'-tetrabromobiphenyl, by halogen-metal exchange and subsequent reaction sequences, a process for the preparation of the asymmetric substituted biaryldiphosphine ligands of formula (I) is provided:n n n [Formula I]n n n n n n n n Cycloalkyl, - [wherein, R 1 is C 1 -6 which is optionally substituted by one or more halogen atoms - C 3-10 alkyl orn n n R 2 and R 3 is aryl, C 5 -10 - cycloalkyl and C 1 -6 - are independently selected from the group consisting of alkyl, wherein each aryl moiety is a halogen atom, nitro, amino, C 1 -6 - alkyl , C 1 -6-alkoxy, and di -C 1 -6 - is optionally substituted with one or more substituents selected from the group consisting of an alkyl group, R 2 and R 3 in each of the C 1 -6-alkyl, C 1 -6 -alkoxy, di-C 1-6 - alkyl, amino and C 5 -10-cycloalkyl group is optionally substituted with one or more halogen atoms. |