Fluorenones are of pharmacological relevance and occur in a number of natural products, such as dengibsin, dengibsinin, or dendroflorin. 1 Fluorenones have been prepared, for example, by intramolecular Friedel–Crafts acylations of biaryls. 2 Snieckus and co-workers reported the synthesis of fluorenones based on remote aromatic metalation. 3 Some years ago, Chan and co-workers reported 4 the synthesis of arenes by [3+3] cyclization of 1,3-bis-silyl enol ...
