Intramolecular Vinylation of Aryl Rings by Vinyl Cations.

A Lewis acid mediated intramolecular electrophilic vinylation of aryl rings by vinyl cations is reported. This reaction takes advantage of β-hydroxy-α-diazo ketones as vinyl cation precursors and provides good yields of tricyclic 1-indenones that contain a seven-membered ring. Extending the alkane chain that tethers the vinyl cation to the aromatic ring leads to 2-napthol and 2-indenone products.