ABSTRACT
Most hydrogenolyses take place over palladium or nickel catalysts at room temperature and atmospheric pressure but the cleavage of a C–C bond of alkyl substituted cyclopropanes is not so easily accomplished with these catalysts. The more substituted the ring, the more difficult the hydrogenolysis over palladium or nickel. Rhodium and ruthenium catalysts are not commonly effective for this reaction and no hydrogenolysis of cyclopropanes occurs over Cu-Ba-CrO catalysts under moderately high reaction conditions. The hydrogenolysis of strained ring systems generally takes place more easily. Spiropentane was cleaved over platinum to give 1,1-dimethyl-cyclopropane as the primary product. Hydrogenolysis of 3,3-dimethyInortricyclene followed the same pattern, primary cleavage of the cyclopropane bond opposite the substituents, to give 7,7-dimethylnorbornane. There are a number of other examples of apparent inversion of configuration taking place on hydrogenolysis of cyclopropanes. The presence of other functional groups in the molecule can also activate the alkyl halide for hydrogenolysis.
