PROCESS FOR THE PREPARATION OF OPTICALLY ACTIVE 3,3-DIPHENYLPROPYLAMINES

The invention relates to a process for obtaining 3,3-diphenylpropylamines of general formula (I), particularly Fesoterodine, as well as their enantiomers, solvates and salts, comprising treating a compound of formula (II) with a chiral alcohol to yield the diastereomeric esters of formula (IV) and (IV'), which can be further transformed into a compound of formula (I), or an enantiomer, solvate or salt thereof, wherein R1 is C1-C8 alkyl; and R2 and R3, independently of one another, represent H or C1-C6 alkyl, or together form a ring of 3 to 7 members with the nitrogen to which they are bound.