New Approach for the Construction of the Coumarin Frame and Application in the Total Synthesis of Natural Products

A new synthetic approach is described for building the coumarin scaffold through the Lewis acid‐promoted cyclization of novel aryl 3‐(dimethylamino)prop‐2‐enoates 2a–2f. The latter precursors were prepared via aminomethylenation of the corresponding aryl acetates 4a–4f with the Bredereck reagent. This approach was used for the synthesis of biologically active natural compounds 1a–1f, through a three‐step procedure starting from the corresponding phenols.