DKR of 8-Amino-5,6,7,8-tetrahydroquinoline

To confirm this racemization mechanism, Crawford et al. added 5 mol % of the ketone to the reaction mixture and obtained the product in 78% yield in 98% ee. This DKR is therefore catalyzed by a carbonyl compound, and can be compared to those shown in Section 4.6. 

---

In 2007, Crawford et al. observed a spontaneous enzymatically mediated DKR of 8-amino-5,6,7,8-tetrahydroquinoline in the presence of Candida antarctica lipase B, in which a >60% yield of the expected enantiopure (R)-acetamide was isolated from the racemic amine. " The spontaneous formation of 5,6,7,8-tetrahydroquinolin-8-one as a side product, followed by a con-densation/hydrolysis sequence with the remaining (5)-8-amino-5,6,7,8-tetra-hydroquinoline via the corresponding enamine, provided the necessary racemisation pathway (Scheme 3.52). 

---