Deracemization, the conversion of a racemic mixture into an enantiomerically enriched material, is achieved with the retro‐aldol reaction of rac‐1 in the presence of lithium (−)‐ephedrinate [Eq. (1)]. Remarkably, two stereogenic centers are simultaneously deracemized. This reaction shows that efficient thermodynamic control of the enantioselectivity of aldol reactions is possible

Deracemisierung, d. h. Umwandlung einer racemischen in eine enantiomerenangereicherte Mischung, gelingt mit der Retro‐Aldol‐Reaktion von rac‐1 in Gegenwart von Lithium‐(−)‐Ephedrinat [Gl. (1)]. Bemerkenswerterweise erfolgt die Deracemisierung dabei an zwei Stereozentren. Anhand dieser Reaktion läßt sich zeigen, daß eine wirkungsvolle thermodynamische Kontrolle der Enantioselektivität von Aldol‐Reaktionen möglich ist.

Deracemization, the conversion of a racemic mixture into an enantiomerically enriched material, is achieved with the retro-aldol reaction of rac-1 in the presence of lithium (-)-ephedrinate [Eq. (1)]. Remarkably, two stereogenic centers are simultaneously deracemized. This reaction shows that efficient thermodynamic control of the enantioselectivity of aldol reactions is possible.