Method for preparing enantiomer of sulfoxide compound, and system for preparing enantiomer

A method for selectively preparing one of enantiomers of a sulfoxide compound having a sulfur atom in a sulfoxide group as an asymmetric center by using recycle HPLC provided with a chiral column, the method comprising:

• a step A for introducing an enantiomer mixture of the sulfoxide compound into the chiral column to optically resolve the enantiomer mixture into one enantiomer and the other enantiomer and collect the one enantiomer,
• a step B for irradiating the other enantiomer which is a residue after collecting in Step A or Step C with light to racemize the enantiomer, during a process of returning the other enantiomer from the column outlet to the column inlet of the chiral column, and
• a step C for introducing the enantiomer mixture of the sulfoxide compound obtained by racemization in Step B into the chiral column to optically resolve the enantiomer mixture into the one enantiomer and the other enantiomer and collect the one enantiomer,
• wherein Step B and Step C are continuously repeated.