Synthesis and acidolysis of 3-endo-azidomethyl- and 3-endo-azidobicyclo[3.3.1]non-6-enes. A novel synthesis of 4-azahomoadamant-4-enes

Abstract

The acidolysis of 3-endo-azidomethylbicyclo[3.3.1]non-6-ene (3) with methanesulphonic acid gave 4-azahomoadamant-4-ene (5) which was also produced from 3-endo-hydroxymethylbicyclo[3.3.1]non-6-ene (6) on treatment with NaN₃–MeSO₃H. The formation of (5) was rationalized by a π route cyclization followed by acidolytic ring expansion of intermediate azides on the basis of acidolysis of dideuterio-derivatives. The above route was extended to synthesis of 2,2-(16) and 7,7-dimethyl-4-azahomoadamant-4-enes (17). The acidolysis of 3-endo-azidobicyclo[3.3.1]non-6-ene (23) gave 2-aza-adamantan-anti-4-ol (26)via a π-N⁺ type cyclization.