Synthesis of heterocyclic propellanes. Preparation and transannular reactions of 5-ethoxycarbonylmethylene-cyclooctanone and the corresponding oximes and hydrazones

5-Ethoxycarbonylmethylene-cyclooctanone ($\text{3}$) is prepared by Wittig monoolefination of dione $\text{1}$ with phosphorus ylide $\text{2}$. Thermal transannular cyclization of oxime $\text{6}$ and phenylhydrazone $\text{12}$ of the ketone $\text{3}$ affords 3-oxa-2-aza- and 2,3-diaza[3.3.3] propellanes $\text{7}$ and $\text{14}$ respectively. Irradiation of ketone $\text{3}$, its oxime $\text{9}$, and its dimethylhydrazone $\text{16}$ furnish 9-oxa-, and 9-aza[3.3.2] propellanes $\text{11}$, $\text{10}$, and $\text{17}$, respectively. In addition to the propellane $\text{14}$, phenylazobicyclo compound $\text{13}$ is also obtained from phenylhydrazone $\text{12}$. The acetyl derivatives $\text{8}$ and $\text{15}$ of propellanes $\text{7}$ and $\text{14}$ are also prepared and studied.