Retention of stereochemistry in the formation and fragmentation of diosmacyclobutanes, and other evidence against a diradical mechanism

Article abstract of DOI:10.1021/om00020a015

Two results argue against a diradical intermediate in the exchange of diosmacyclobutanes with free olefins. The diosmacyclobutane Os₂(CO)₈(μ-propene) reacts with vinylcyclopropane to give as the sole product a diosmacyclobutane bearing an intact cyclopropane ring. Repeated exchange of trans-ethylene-1,2-d₂ with the same ligand in a diosmacyclobutane shows >99.1% stereochemical excess per exchange half-life. These exchange reactions do not involve mononuclear olefin complexes.