M. Balci et al., STRUCTURE OF A RING ENLARGED PRODUCT FROM THE BASE-INDUCED REARRANGEMENT OF DIBROMOMETHYLENEBENZONORBORNENE, Journal of chemical crystallography, 26(6), 1996, pp. 413-418
The base-catalyzed rearrangement reactions of 2-bromomethylenebenzonor
bornene 8 and 2,2-dibromomethylenebenzonorbornene 9 were studied. Reac
tion of 8 with potassium tert-butoxide in THF gave only the enol ether
11 whose formation is rationalized via a carbene-cycloalkyne mechanis
m. However, treatment of 9 with phenyllithium in THF at 40 degrees C g
ave the ring-enlarged dibromide 13 whose structure is reported herein.
The ring-enlarged product 13 is rationalized in terms of carbanionic
rearrangement. Quantum mechanical calculations are consistent with the
se observations.