Scalable enantioseparation of amino acid derivatives using continuous liquid-liquid extraction in a cascade of centrifugal contactor separators

Using a cascade of six centrifugal contactor separators in a countercurrent liquid-liquid extraction mode allowed the separation of one of the enantiomers of 3,5-dinitrobenzoyl-leucine in 55% yield and 98% ee using a catalytic amount of a chiral host compound based on a cinchona alkaloid. This method allows the preparation of kilograms of enantiopure material in table-top-sized equipment that can be operated in a fume cupboard. The methodology can be easily scaled up to ton amounts as large- volume centrifugal contactor separators are commercially available as well.