Process for preparing sertraline intermediates

Abstract From the Canadian patent

A novel three-step process for preparing 4-(3,4dichlorophenyl)-4-phenylbutanoic acid is disclosed which involves (1) reducing 4-(3,4-dichlorophenyl)- 4-ketobutanoic acid to 4-(3,4-dichlorophenyl)-4hydroxybutanoic acid; (2) then converting the intermediate hydroxy acid formed in the first step to 5-(3,4-dichlorophenyl)-dihydro-2(3H)-furanone and (3), thereafter reacting the resulting gamma-butyrolactone compound with benzene in a Friedel-Crafts type reaction to form the desired final product. The latter compound is known to be useful as an intermediate leading to 4-(3,4-dichlorophenyl)-3,4-dihydro-1(2H)-naphthalenone and ultimately, to …