TFP as a ligand in Au(I)-catalyzed dihydropyran synthesis. Unprecedented rearrangement of dihydropyrans into cyclopentenones

Dihydropyrans have been prepared by the cyclisation of easily accessible propargyl vinyl ethers with (TFP) AuCl/AgBF4 as a catalyst in high yields. These compounds undergo acid-catalysed rearrangement into cyclopentenone derivatives.