Tertiary amide-based Knoevenagel-type reactions: a direct, general, and chemoselective approach to enaminones

We report one-pot and chemoselective Knoevenagel-type reactions using highly stable amides and lactams as the electrophilic substrates. The method is based on the in situ activation of amide carbonyl with triflic anhydride and a subsequent reaction with carbanions generated in situ from carbonyl compounds. The amide-based method is an alternative to the versatile thioamide-based Eschenmoser sulfide contraction.