AN EXAMINATION OF BETA-ENOLIZATION IN BENZOBICYCLO[2.2.2], [3.2.1], AND [3.2.2] KETONES

Under homoenolization conditions (t-BuO-/t-BuOH/185-degrees-C), the 3, 3-dimethylbenzobicyclo[2.2.2]- and [3.2.1]octen-2-ones (7, 8) and thei r [3.2.2] homolog (9) each undergo beta-enolate rearrangement to a sin gle ketone. These rearrangement processes, however, are in competition with Haller-Bauer cleavage, in contrast to the behavior of bicyclo[2. 2.2]octenone, which is not cleaved under these reaction conditions, al though Haller-Bauer cleavage was found as a minor process for the [3.2 .1] and [3.2.2] analogs. The structures of all products were determine d primarily from their H-1 and C-13 magnetic resonance spectra.