Olefin oxygenation by the hydroperoxide adduct of a nonheme manganese(IV) complex: epoxidations by a metallo-peracid produces gentle selective oxidations.
The reactive intermediates and mechanisms of oxygenation of olefins by manganese complexes were investigated by treating olefins with newly synthesized [MnIV(Me2EBC)(OH)2](PF6)2 in the presence and absence of peroxide and by studying its catalytic epoxidation reaction in normal aqueous solution and, individually, with isotopically labeled H218O, 18O2, and H218O2. The manganese oxo species is not the reactive intermediate for the oxygen transfer process mediated by this manganese complex. A novel manganese(IV) peroxide intermediate, MnIV(Me2EBC)(O)(OOH)+, was captured by mass spectrometry and is proposed as the intermediate that oxygenates olefins in this catalytic system.
Yin
Guochuan
G
Department of Chemistry, The University of Kansas, Lawrence, Kansas 66045, USA.
Buchalova
Maria
M
Danby
Andrew M
AM
Perkins
Chris M
CM
Kitko
David
D
Carter
John D
JD
Scheper
William M
WM
Busch
Daryle H
DH