SOME STERIC ASPECTS IN THE CYCLOPROPANATION OF NORBORNADIENE

The addition of ethyl diazoacetate at norbomadiene catalyzed by pi-all yl palladium chloride has been investigated. This reaction is exo-ster eospecifical. From the reaction mixture three isomeric diadducts were separated with the exo-exo configuration of cyclopropane rings: tetrac yclo [3.3.1.0(2,4).0(6,8)] nonane - 3,7 - diethylester [1 alpha, 2 bet a, 3 alpha, 4 beta, 5 alpha, 6 beta, 7 alpha, 8 beta] (8); tetracyclo [3.3.1.0(2,4) 0(6,8)] nonane - 3,7 - diethytester (1 alpha, 2 beta, 3 alpha, 4 beta, 5 alpha, 6 beta, 7 beta, 8 beta), (9); tetracyclo [3.3. 1.0(2,4) 0(6,8)] nonane - 3,7 - diethylester (1 alpha, 2 beta, 3 alpha , 4 beta, 5 alpha, 6 beta, 7 alpha, 8 beta), (10). These compounds dif fer only in the configuration of the carboethoxy group. High-resolutio n H-1- and C-13-NMR-spectra are disscused underlining the stereochemic al peculiarities and the structural assignments.