Bis-aluminated triflic amide promoted Diels–Alder reactions of α,β-unsaturated lactones

The bis-aluminated triflic amides such as TfN[Al(Me)Cl]2 and TfN[Al(iBu)2]2, which are derived from triflic amide (1 mol) and aluminum reagent (2 mol), can efficiently promote the Diels–Alder reaction of α,β-unsaturated lactone derivatives as dienophiles. Selection of the ligand on aluminum of these Lewis acids should be important depending on the combination of dienophile and 1,3-diene.