Heterocycles 36. Single-Walled Carbon Nanotubes-Bound N,N-Diethyl Ethanolamine as Mild and Efficient Racemisation Agent in the Enzymatic DKR of 2-Arylthiazol-4-yl-alanines

In this paper we describe the chemoenzymatic synthesis of enantiopure l-2-arylthiazol-4-yl alanines starting from their racemic N-acetyl derivatives; by combining the lipase-catalysed dynamic kinetic resolution of oxazol-5(4H)-ones with a chemical and an enzymatic enantioselective hydrolytic step affording the desired products in good yields (74%-78%) and high enantiopurities (ee > 99%). The developed procedure exploits the utility of the single-walled carbon nanotubes-bound diethylaminoethanol as mild and efficient racemisation agent for the dynamic kinetic resolution of the corresponding oxazolones.