LREO3 EPOXIDIZES, CIS-DIHYDROXYLATES, AND CLEAVES ALKENES AS WELL AS ALKENYLATES ALDEHYDES - TOWARD AN UNDERSTANDING OF WHY

The relative reaction thermodynamics for the probable pathways leading to alkene epoxidation, cis-dihydroxylation, and C-C cleavage as well as alkenylation of aldehydes have been investigated for the reaction o f ethylene with LReO3, L = CH3, Cl, OH, OCH3, O-, C5H5(Cp), and C-5(CH 3)(5) (Cp) We find the reaction pathway exothermicities to be quite s ensitive to the ligand. For ClReO3, CH3ReO3, HOReO3, CH3OReO3, and O-R eO3, reaction with ethylene is endothermic with metallaoxetane preferr ed over dioxylate formation. For CpReO3 and CpReO3, the reaction with ethylene is exothermic but nearly thermoneutral with dioxylate format ion preferred. The pi-binding attributes of the ligand are found to co rrelate with thermodynamic preference.