Generation of Absolute Controlled Crystal Chirality by the Removal of Crystal Water from Achiral Crystal of Nucleobase Cytosine

[Image: see text] The enantioselective formation of chiral crystal of achiral nucleobase cytosine was achieved mediated by the crystal direction selective dehydration of crystal water in the achiral crystal of cytosine monohydrate (P2(1)/c). Heat transfer from the enantiotopic face of the single crystal of cytosine monohydrate afforded the enantiomorphous crystal of anhydrous cytosine.