Ruthenium-catalyzed cyclopropanation of norbornene with propargyl alcohol

Article abstract of DOI:10.1246/bcsj.72.2475

Norbomene as well as its 5,6-disubstituted derivatives and oxa- norbornene undergoes a novel cyclopropanation with propargyl alcohol in methanol containing cationic (η⁵- cyclopentadienyl)tris(acetonitrile)ruthenium complexes as catalysts to give exo-3-acetyltricyclooctane derivatives. Cyclopentadienylruthenium catalysts having an electron-withdrawing substituent on the Cp ligand exhibited the highest activity and the cyclopropanation proceeded even at -20 °C. On the basis of a deuterium labeling experiment, a reaction mechanism involving a ruthenacycle intermediate is proposed.