From evolution to green chemistry: rationalization of biomimetic oxygen-transfer cascades.
Thermodynamic electron-transfer potentials from biology textbooks elucidate the sequence of electron-transfer events in the respiratory chain in mitochondria. In this study, thermodynamic and kinetic oxygen-transfer potentials have been defined and predicted for oxidants and substrates using density functional theory, aiming to rationalize multiple oxygen-transfer events in chemical catalysis, particularly in current developments of the Sharpless dihydroxylation. Key transition states for competing mechanisms in a recent dihydroxylation method containing the olefin, osmium tetraoxide, methyltrioxorhenium(VII), a chiral tertiary amine, and the green terminal oxidant hydrogen peroxide have been investigated rigorously. The calculations show the amine to function as an oxygen-transfer mediator between rhenium peroxides and osma-2,5-dioxolanes, in addition to its role as a carrier of chiral information. Unique mechanistic and stereoelectronic patterns in this oxygen-transfer cascade explain the unexpected failure of reactivity predictions using simpler models such as Marcus theory.
Deubel
Dirk V
DV
Swiss Center for Scientific Computing, ETH Zürich, 6928 Manno, Switzerland. metals-in-medicine@phys.chem.ethz.ch
D005075:Biological Evolution; D040761:Biomimetic Materials / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry* / Q000378:metabolism; D013816:Thermodynamics
D010087:Oxides; D006861:Hydrogen Peroxide; D010100:Oxygen