Synthesis of Optically Active Oxazolines from Optically Active Epoxides.

Abstract The reaction of optically active terminal epoxides, which were produced by a microbial reaction, with acetonitrile in the presence of a protic acid or Lewis acid was studied. 1,2-Epoxyoctane, 2-methyl-1,2-epoxyhexane, and pentafluorostyrene oxide gave the corresponding 4-substituted 2-methyl-2-oxazoline derivatives with moderate to excellent regioselectivity. The reactions proceeded with an inversion of the asymmetric center with high stereospecificity under AlCl 3 - or SnCl 4 -catalyzed conditions, while partial racemization occurred under HF- or CF 3 SO 3 H-catalyzed conditions. The acid used and the substituent on the epoxide affected the stereospecificity and regioselectivity of the oxazoline formation. 4-Hexyl-2-methyl-2-oxazoline obtained with high stereospecificity was converted into 2-aminooctanoic acid via 2-aminooctanol.