Preparation of β-trifluoroacetylated lactams 1a (n=0), 1b (n=1) and 2a (n=1) : Lactam was treated first with 1.5 eq. of NaH in boiling THF followed by ethyl trifluoroacetate (1.5 eq.). For β-trifluoroacetylated lactams 1c (n=2) and 2b (n=2) : Lactam was treated with 1.3 eq. of lithium diisopropyl amide at −78°C followed by addition of ethyl trifluoroacetate (1.2 eq.) at −20°C. ... All compounds in scheme 3 are characterized by IR, 1 H-NMR, 19 F-NMR, 13 C-NMR and MS.
