Stereochemistry modulates the catalytic hydrogenolysis of nitrile-substituted cyclopropanes

The study of Raney-Ni catalyzed chemo- and regioselective hydrogenolysis of diastereomeric nitrile-substituted spirocyclopropyloxindoles is presented. The chemoselectivity outcome of the reaction is remarkably influenced by the relative stereochemistry of the nitrile-substituted spirocyclopropyclopropyloxindoles. Chemo- and high regioselective cyclopropane ring-opening occurs from the syn diastereomers to give the corresponding 3-propylacetamide derivatives. X-ray crystallographic studies together with DFT model chemistry calculations indicate that chemo- and regioselectivity are directly dependent on the bond length asymmetry of the cyclopropane ring.