Shortened synthesis of 3,3-diarylpropylamine derivatives

A process for the production of 3,3-diarylpropylamines of the general formula I

• wherein
• R is selected from the group consisting of hydrogen, straight-chained and branched C1-C8 alkyl, R′ and R″ can be the same or different and are selected from the group consisting of straight-chained and branched C1-C6 alkyl, the process comprising condensing a compound of general formula 1
• wherein R is defined as above, with cinnamic acid to form a compound of the general formula 2a
• then reacting the compound of general formula 2a with a tertiary chiral amine to form a compound of the general formula 2b
• subsequently, treating the compound of the general formula 2b by acidification to isolate a compound of formula 3
• in crystalline form, which is converted, via an intermediate step of an acid chloride, with continuing ester formation with alcohols of the formula R—OH, wherein R is defined as above, to a compound of the general formula 4
• and, in a further reaction step, hydrogenating the compound of the general formula 4 using diisobutylaluminium hydride or lithium tri-tert.-butoxyaluminium hydride, to lactols of general formula 5
• and reductively aminating the compound of general formula 5 with primary, secondary or tertiary amines to form compounds of the general formula I
• wherein R, R′ and R″ are defined as above.