Ring Expansion through [2+2] Photocycloaddition–β-Scission Sequence. Two Carbon Ring Expansions of β-Indanone and β-Tetralone

We describe a new method for two carbon ring expansions of 5-and 6-membered rings of β-indanone and β-tetralone through the [2+2] photocycloaddition of the enol ethers of the cyclic ketones followed by the radical cleavage of the fused bond of the cyclobutanols derived from the adducts.