Ruthenium-Catalyzed Cyclopropanation of Norbornene with Propargyl Alcohol

Abstract

Abstract Norbornene as well as its 5,6-disubstituted derivatives and oxa-norbornene undergoes a novel cyclopropanation with propargyl alcohol in methanol containig 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.