Ring Expansion and Skeletal Rearrangement of Propargyl Alcohol Substituted Aziridines Induced by Ruthenium Complexes

The ring expansion and skeletal rearrangement of two types of propargyl alcohol substituted aziridines with or without cycloalkane moieties was induced by a ruthenium cyclopentadienyl phosphine complex. In the simple aziridine system with no cycloalkane, the unique cycloisomerization process altered the absolute connectivity of the two-carbon unit in the three-membered ring to give organometallic products with substituted pyridine or dihydropyridine ligands. For the aziridine on a cyclohexyl ring, the cycloisomerization process was controlled by an interchange process between vinylidene and allenylidene species, thus creating a better relative configuration of the aziridinyl and the alkynyl units. This determines the stereochemistry of the metal carbene products of the octahydroindole derivatives. The structures of five products were determined by X-ray diffraction analysis.