Preparation and properties of cage polycyclic systems. Part IV. Hydrogenolyses of homocubane derivatives

Abstract

Hydrogenolyses and deuteriolyses of several homocubanes (pentacyclo[4.3.0.0^2,5.0^3,8.0^4,7]nonanes) in the presence of platinum-, palladium-, and rhodium-supported catalysts are described. 4-X-Homocubanes absorb 1 mol. equiv. of hydrogen to give 5-X-tetracyclo[4.3.0.0^2,5.0^3,8]nonanes by cleavage of the C(2)–C(5) bond. 9,9-Ethylenedioxypentacyclo[4.3.0.0^2,5.0^3,8.0^4,7]nonane, in the presence of rhodium–alumina (or rhodium–carbon), is hydrogenolysed by endo,endo-addition of hydrogen to give 3,3-ethylenedioxytetracyclo[4.3.0.0^2,8.0^4,7]nonane [by cleavage of the C(4)–C(5) bond] and 9,9-ethylenedioxytricyclo[4.3.0.0^3,8]nonane [by successive cleavage of the C(2)–C(5) and C(4)–C(7) bonds].