When ethyl 2-substituted-1-indanone-2-carboxylates were treated with samarium diiodide (SmI2), ring expansion products such as 3-substituted-1, 2-naphthoquinones were isolated. Alcohols were also obtained as the mixture of cis-and trans-isomers of hydroxy and ester substituents. A reaction mechanism involving intramolecular addition of samarium ketyl radicals to ester substituents followed by ring expansion was proposed for the formation of ...