The Lactol Route to Fesoterodine: An Amine-Promoted Friedel–Crafts Alkylation on Commercial Scale

Abstract

We report the discovery and optimization of an amine-promoted Friedel–Crafts alkylation of cinnamaldehyde with 4-hydroxymethyl phenol. This reaction has been used successfully on commercial scale (200 kg) in the context of the manufacture of fesoterodine, a muscarinic antagonist used for the treatment of overactive bladder. Reductive aminations of diisopropylamine and lactol 4 are also discussed, as well as the resolution of the racemic amine rac-2 into its enantiomerically pure form.