Silver-Catalyzed Cyclization of ortho-Carbonylarylacetylenols for the Synthesis of Dihydronaphthofurans

ortho-Carbonylarylacetylenols have been employed for the synthesis of dihydronaphthofurans via AgTFA-catalyzed annulation reaction. A broad range of substrates both ortho-keto- and ortho-formylarylacetylenols could be employed in this transformation providing the desired products in good yields. However, the reaction pathways of these two substrates are different. The reaction of the ketone precursors could directly lead to the desired products in a single Operation while the reaction of the aldehyde precursors required a one-pot two-step approach, without isolation of the bicyclic acetal intermediates. In addition, this method was also successfully used for the synthesis of dihydronaphthopyrans in very good yields.