Towards the syntheses of α-trifluoromethylated oxygenated heterocycles and their precursors

The possibilities of synthesizing various α-trifluoromethylated oxygenated heterocycles, starting from trifluoroacetaldehyde methyl hemiacetal, through classic cyclization reactions, have been demonstrated. In this way, six-membered cyclic compounds, δ-lactones and also macrolactones, bearing a CF 3 group in a position a to the oxygen could be easily obtained through a RCM reaction. Bicyclic compounds could be also synthesized by an intramolecular Pauson-Khand reaction.