Publication year: 2011 Source: Computational and Theoretical Chemistry, Available online 29 September 2011 Richard Tia, Evans Adei The oxidation of ethylene by osmium tetroxide (OsO4), osmyl hydroxide (OsO2(OH)2)and osmyl chloride (OsO2Cl2) have been studied by hybrid density functional theory at the B3LYP/LACVP∗ level of theory. It was found that in the reaction of OsO4with ethylene, the [3+2] addition pathway leading to a five-membered metallacycle intermediate is more favorable than the [2+2] addition to form a four-membered metallaoxetane and that the reaction leads ultimately to the formation of diols without epoxide formation, in agreement with earlier works on the subject. The reaction of ethylene with osmyl hydroxide (OsO2(OH)2), which is released when the ‘cyclic’ esters formed from [3+2] reaction of OsO4with ethylene undergo hydrolysis, was found to be less favorable, kinetically and thermodynamically, than the [3+2] reaction of OsO4with ethylene.
[3+2] versus [2+2] Addition of Metal Oxides Across C=C Bonds: A Theoretical Study of the Mechanisms of Oxidation of Ethylene by Osmium Oxide Complexes
Publication year: 2011 Source: Computational and Theoretical Chemistry, Available online 29 September 2011 Richard Tia, Evans Adei The oxidation of ethylene by osmium tetroxide (OsO4), osmyl hydroxide (OsO2(OH)2)and osmyl chloride (OsO2Cl2) have been studied by hybrid density functional theory at the B3LYP/LACVP∗ level of theory. It was found that in the reaction of OsO4with ethylene, the [3+2] addition pathway leading to a five-membered metallacycle intermediate is more favorable than the [2+2] addition to form a four-membered metallaoxetane and that the reaction leads ultimately to the formation of diols without epoxide formation, in agreement with earlier works on the subject. The reaction of ethylene with osmyl hydroxide (OsO2(OH)2), which is released when the ‘cyclic’ esters formed from [3+2] reaction of OsO4with ethylene undergo hydrolysis, was found to be less favorable, kinetically and thermodynamically, than the [3+2] reaction of OsO4with ethylene.
