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

Abstract

A new synthetic approach is described for building the coumarin scaffold through the Lewis acidpromoted 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.