Development of a Stereoselective and Scalable Synthesis for the Potent Indoleamine 2,3-Dioxygenase 1 (IDO1) Inhibitor, BMT-297376; N‑((R)‑1-((cis)‑4-(3-(Difluoromethyl)-2-methoxypyridin-4-yl)cyclohexyl)propyl)-6-methoxynicotinamide

The current work describes a stereoselective and scalable route to N-((R)-1-((cis)-4-(3-(difluoromethyl)-2-methoxypyridin-4-yl)­cyclohexyl)­propyl)-6-methoxynicotinamide (1) from readily available 1,4-dioxaspiro[4.5]­decan-8-one. The developed process encompasses an efficient 1,4-trans-selective synthesis of (trans)-4-(3-(difluoromethyl)-2-methoxypyridin-4-yl)­cyclohexyl methanesulfonate as the key intermediate and the use of Ellman sulfinamine methodology to install an alkyl amine in a stereoselective manner. Various synthetic routes were screened to accomplish a stereoselective and scalable protocol to access the title compound (1). This advancement enabled a competent route to the title compound in an enantioselective, safe, cost-effective, and scalable manner.