Total spontaneous resolution by deracemization of isoindolinones.

Separated: 3-hydroxy-3-phenylisoindolin-1-ones have been resolved by dynamic preferential crystallization. The compounds were effectively racemized through ring-opening and ring-closing reactions via achiral intermediates under basic conditions. Crystallization from a toluene solution containing 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) with stirring and evaporation of the solvent gave optically active crystals quantitatively with high ee values.