... Tetrahedron: Asymmetry. Volume 12, Issue 11, 4 July 2001, Pages 1583–1587. ... 12 Nucleophilic substitution of ethyl (S)-2-methanesulfonyloxyl-4-phenylbutanoate 7 with potassium acetate in DMF in the presence of 18-crown-6 provided, after hydrolysis, (R)-1 in 47% yield and 74 ...