IVESTIGATIONS OF THE MECHANISM OF THE Rh/Cu- AND Rh-CATALYZED OXIDATION OF TERMINAL OLEFINS WITH O2

Article abstract of DOI:10.1021/ja00296a011

The mechanism of the Rh(III9-catalyzed oxidation of 1-hexene to 2-hexanone, both with and without a Cu(II) co-catalyst, is investigated.In the absence of Cu(II), only one oxygen atom of dioxygen is found to be incorporated into ketone product.This contrasts with the previously reported observation that in the presence of the Cu(II) co-catalyst both oxygen atoms of O2 are incorporated into product.Similaly, the Rh(III) catalyst without Cu(II) isomerizes 1-hexene to a large extent, in contrast to the previously reported Rh/Cu catalyst system.Both acetone and water are found to be produced continously when isopropyl alcohol is the absence of Cu(II), while neither are formed continuosly when Cu(II) is present.Furthermore, itis shown that H"O" and t-BuOOH may be used as the 1-hexene oxidant under anaerobic conditions in the presence or absence of Cu(II), producing 2-ketone.These observations are incorporated into tentative mechanisms which specify key roles for copper that lead to differences in reactivity.