In this paper, we report the development of different synthetic routes to MK-7246 (1) designed by the Process Chemistry group. The syntheses were initially designed as an enabling tool for Medicinal Chemistry colleagues in order to rapidly explore structure-activity relationships (SAR) and to procure the first milligrams of diverse target molecules for in vitro evaluation. The initial aziridine opening/cyclodehydration strategy was also directly amenable to the first GMP deliveries of MK-7246 (1), streamlining the transition from milligram to kilogram-scale production needed to support early preclinical and clinical evaluation of this compound. Subsequently a more scalable and cost-effective manufacturing route to MK-7246 (1) was engineered. Highlights of the manufacturing route include an Ir-catalyzed intramolecular N-H insertion of sulfoxonium ylide 41 and conversion of ketone 32 to amine 31 in a single step with excellent enantioselectivity through a transaminase process. Reactions such as these illustrate the enabling impact and efficiency gains that innovative developments in chemo- and biocatalysis can have on the synthesis of pharmaceutically relevant target molecules.

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MK-6096 is an orexin receptor antagonist in clinical trials for the treatment of insomnia. Herein we describe its first kilogram-scale synthesis. Chirality on the α-methylpiperidine core was introduced in a biocatalytic transamination using a three-enzyme system with excellent enantioselectivity (>99% ee). Low diastereoselectivity of the lactam reduction was overcome by development of a camphor sulfonic acid salt formation and dr upgrade. A chemoselective O-alkylation with 5-fluoro-2hydroxypyridine was optimized and developed. Overall, 1.2 kg of MK-6069 was prepared in nine steps and 13% overall yield.