Efficient syntheses of the hitherto unknown hydrocarbons dispiro[2.1.4.1]de
cane and dispiro[2.0.3.3]decane have been realized through reaction sequenc
es involving spiro[3.4]octan-2-one and spiro[3.4]octan-5-one as key interme
diates. (C) 2000 Elsevier Science Ltd. All rights reserved.