4H-cyclopenta[def]phenanthren-1-yl acetate gave 2- and 7-acetyl derivatives. The reaction of isomeric 2-acetoxy compound afforded 1- and 7-acetyl derivatives. The acetyl group of the 3- and 8-acetoxy compounds rearranged into the 2- and 9-positions, respectively. In addition, 1-, 2-, 3-, 4-isopropyl compounds were derivedfrom the corresponding acetyl derivatives.