Optical Resolution of (RS)-Pantolactone through Amide Formation

The optical resolution of (RS)-pantolactone ( 1 ) is carried out through formation of diastereoisomeric amides. These are separated by a single hot washing with CH₂C1₂ or CHC1₃. The used asymmetric amine, (1R)-3-endo-aminoborneol ( 4 ), is readily accessible and can be recovered almost quantitatively after resolution.