Practical Asymmetric Synthesis of an Edivoxetine·HCl Intermediate via an Efficient Diazotization Process

A convergent synthesis of (S)-(4-benzylmorpholin-2-yl)­(morpholino)­methanone methanesulfonate (1), a key regulatory starting material for edivoxetine·HCl, was developed at Eli Lilly & Company. This novel synthesis utilizes d-serine as the source of chirality, which is preserved throughout the synthesis. Key features include the development of a scalable diazotization process to produce (S)-epoxy acid 7, which was optimized to improve the process safety profile. The final (S)-morpholino acid intermediate 11 was converted to the title compound using T3P with >99.9% purity in 75% yield. Life cycle analysis of the new route revealed a 69% reduction in global warming potential (GWP) for solvent usage relative to the prior route of manufacture.