SPANamine derivatives in the catalytic asymmetric α-fluorination of β-keto esters

The use of C-2-symmetric enantiopure nitrogen ligands in the asymmetric catalytic alpha-fluorination of beta-ketoesters is described. SPANamine 1 in the presence of nickel salts gives up to 63% ee in the fluorination of tert-butyl 2-oxocyclopentanecarboxylate with N-fluorosuccinimide (NFSI). The same enantioselectivity is obtained when SPANamine 1 is used as an organocatalyst, although the reaction is much slower. (C) 2011 Elsevier Ltd. All rights reserved.