Facets of the chemistry of some azabicycles.

The silver-ion catalyzed solvolysis of 2-chloro-2-azabicyclo [2.2.1] hept-5-ene and 2-chloro-2-azabicyclo [2.2.2] oct-5-ene was investigated. These compounds were found to solvolyse with assistance from the olefinic double bond, rearranging to 1-azabicyclic systems. In the former case, further reaction to tricyclic structures was observed. Comparison of these results with those for the solvolysis of 2-chloro-2-azabicyclo [2.2.l] heptane and 2-chloro-2-azabicyclo [2.2.2] octane showed a close parallel; the heptane/heptane systems were observed to retain chlorine in their initial solvolysis products, while the octane/octane homologues did not. The reasons for chlorine retention are discussed, and the phenomenon is related to the structure of the original N-chloroamine. Alumina was found to be an effective catalyst for the rearrangement of 2-chloro-2-azabicyclo [2.2.l] hept-5-ene and 2-chloro- 2-azabicyclo [2.2.l] heptane, superior in most respects to silverion. A novel reaction of certain of these chloramines (thermolytic conversion to the corresponding amine hydrochlorides) is also reported. Factors affecting the ratio of invertomers in strained 2-azabicyclic and 7-azabicyclic chloramines were also studied. In the 2-azabicyclic systems, the invertomer ratio appeared to depend largely on the relative severity of the steric interactions in the two invertomers. In 7-Chloro-7-azabenzonorbomadienes and 7-chloro-7-azabenzonorbomenes, however, electronic influences on the ratio of invertomers were demonstrated by variation of the substituents on the benzene ring, thus altering the character of the aromatic p orbital without affecting molecular stereochemistry. It was concluded that the varying character of the aromatic orbital affected the invertomer ratios by a mechanism essentially electrostatic in nature.