20 Twenty-Five Years’ History, Mechanism, and Generality …
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generation of chiral racemic organic salts 1 (Fig. 20.2), which were the derivatives of
racemic 1a, in terms of a unique polymorphic transition occurring during crystallization (Fig. 20.3) [25, 26]. The propriety of this proposed mechanism was verified by the
Fig. 20.3 Mechanism of PE in the case of crystallization of the supersaturated solution of slightly
R-enriched compounds 1. Homochiral 1D molecular association (a, f) in the supersaturated solution
and b, f in the metastable crystals, c polymorphic transition followed by d selective redissolution
of the excess R enantiomer into the mother liquor, and e deposition of nonracemic mixed crystals
slightly enriched with the opposite S enantiomer
409
generation of chiral racemic organic salts 1 (Fig. 20.2), which were the derivatives of
racemic 1a, in terms of a unique polymorphic transition occurring during crystallization (Fig. 20.3) [25, 26]. The propriety of this proposed mechanism was verified by the
Fig. 20.3 Mechanism of PE in the case of crystallization of the supersaturated solution of slightly
R-enriched compounds 1. Homochiral 1D molecular association (a, f) in the supersaturated solution
and b, f in the metastable crystals, c polymorphic transition followed by d selective redissolution
of the excess R enantiomer into the mother liquor, and e deposition of nonracemic mixed crystals
slightly enriched with the opposite S enantiomer