A Novel Anionic Condensation, Fragmentation, and Elimination Reaction of Bicyclo[2.2.1]heptenone Ring Systems RainierJon D. XuQing 1999 We have identified an unprecedented anionic condensation, fragmentation, and elimination sequence from the coupling of bicyclo[2.2.1]heptenones with aldehydes. This reaction leads to the stereoselective formation of disubstituted five-membered rings which are present in a wide array of bioactive molecules.