Scalable Flow Method Yields Enantiomerically Pure Pharmaceutical Intermediates

Uniqsis report how researchers at Lilly S.A (Madrid, Spain) have developed a novel continuous flow approach for the Wadsworth–Emmons cyclopropanation of alkyl-substituted chiral epoxides into chiral cyclopropane carboxylic acids.

Employing a FlowSyn continuous flow reactor and binary pump in a custom set-up the researchers developed a new flow process which circumvented the risks associated with the high temperature and pressure required, and the highly volatile nature of the epoxide starting material.

Additionally, the researchers reported that the FlowSyn flow reactor offered increased efficiency, as its reduced headspace contributes to keeping a higher concentration of the low-boiling-point reactants in the liquid phase and thus enhanced reactivity, contrary to the use of sealed vessels in batch.

Using the described approach the researchers coupled their cyclopropane formation process with in-line workup and hydrolysis transformations to yield the desired enantiomerically pure cyclopropane carboxylic acids in good yields up to the 100 g scale. To read this paper in full please visit https://pubs.acs.org/doi/10.1021/acs.oprd.3c00444#