Development of a Scalable Synthesis of trans-4-Fluorocyclohexylamine via Directed Hydrogenation

Herein, a scalable and practical process to prepare trans-4-fluorocyclohexylamine hydrochloride (1a) is described. By exploitation of the embedded gem-difluoride motif in the commercially available 4,4-difluorocyclohexanecarboxylic acid, a derived orthoester-masked acid underwent dehydrofluorination to provide the requisite vinyl fluoride for a directed hydrogenation event, enabling selective access to the trans-configuration of 1a.