Effects of annulation on the mass spectral behavior of bicyclo[4.3.0]-3-nonene derivatives: Aldehydes

The mass spectra of the title compounds depend markedly on ring annulation. On ionization, the cis-annulated isomers lose alcohol and benzene regardless of the configuration of the alkoxyl. In the trans-annulated isomers, the fragmentation is governed by the configuration of both the aldehyde and the alkoxyl groups. The role of non-bonding interactions is discussed.