A Small Molecule Diacid with Long-Term Chiral Memory

A small, axially chiral diacid was designed with chiral memory based on restricted rotation. Heating a racemic sample with a chiral alkaloid led to an enantiomeric excess of up to 40% ee. The guest-induced chirality was preserved on cooling to rt, which was maintained even in the absence of guest (t(1/2) = 14y). The chiral enrichment process was also reversible, allowing the diacid to be used as a chiral switch.