Development and Scale-Up of an Asymmetric Synthesis of AZD8186 Using the Fukuyama Modification of the Mitsunobu Reaction

A large-scale asymmetric synthesis has been developed for the kilo-lab manufacture of AZD8186. The process initially employs a regioselective Heck coupling in water to provide the starting aromatic ketone. This ketone is reduced asymmetrically under ruthenium-catalyzed transfer hydrogenation conditions to provide a chiral alcohol in high enantiomeric purity. The key synthetic step then requires the reaction of this chiral alcohol with the activated derivative of 3,5-difluoroaniline under the Mitsunobu reaction conditions. The common issues associated with the use of the Mitsunobu reaction, such as removal of triphenylphosphine oxide and reduced diisopropyl azodicarboxylate (DIAD) by-products, have been eliminated through crystallization of the relevant intermediates.