<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Complete racemization of (S)‐(I) and (S)‐(II) can be achieved using 1, 5, 7‐triazabicyclo[4.4.0]dec‐5‐ene (TBD) as base in methyl‐ or ethyl tert‐butyl ether (MTBE) or (ETBE).</p> </abstract>