A novel synthesis of enantiomerically pure 5,5,5,5′,5′,5′-hexafluoroleucine

[GRAPHICS] A novel, short, and efficient synthesis of (S)-5,5,5,5 ' ,5 ' ,5 ' -hexafluoroleucine (6) in greater than 99% ee starting from the protected oxazolidine aldehyde 1 is described. The enantiomeric excess of the product was calculated from an NMR analysis of a dipeptide formed by reaction with a protected L-serine derivative. Furthermore, a racemic sample of N-acylated hexafluoroleucine was enzymatically resolved by treatment with porcine kidney acylase I and was found to have the same optical rotation as a synthetic sample of 6.