Process for the preparation of tolterodine and intermediates thereof

A process for the preparation of 6-methyl-4-(R)-phenyl-chroman-2-one (Ia)

• or 6-methyl-4-(S)-phenyl-chroman-2-one (Ib),
• comprising the reaction of 6-methyl-coumarin (II)
• with a compound selected from the group consisting of formulae (III), (IV), (V), and (VI)
• in the presence of a chiral catalyst, in which:
• in the compound of formula (III), each of R1 and R2 is independently a hydrogen atom, a C1–C6 alkyl group, an optionally substituted aryl or heteroaryl group;
• or R1 and R2, taken together, form a C2–C6 alkylene chain;
• or —OR1 and —OR2, taken together with the boron atom they are linked to, form a group of formula
• in the compounds of formula (IV) and (VI) Ph is phenyl;
• in the compound of formula (V) M+ is a metal cation selected from Li, Na, K, Rb and Cs;
• and
• in the compound of formula (VI) R is a C1–C6 alkyl group.