Peroxo-dimolybdate catalyst for the oxygenation of organic sulfides by hydrogen peroxide

Synthesis, structure and catalytic olefin epoxidation activity of a dinuclear oxo-bridged oxodiperoxomolybdenum(VI) complex containing coordinated 4,4′-bipyridinium

“…Although complex 1 and several previously reported dinuclear complexes share related structural features, particularly regarding the central oxodiperoxo-molybdenum(VI) [18,19,[35][36][37] or oxodiperoxo-tungsten(VI) [38][39][40] unit, the neutral complex [{MoO(O 2 ) 2 (4,4 -Hbipy)} 2 ( -O)] is the first example in which the metal centers are coordinated to one organic moiety. Typically, …”

“…Typically, an amount of catalyst equivalent to 18 mol of Mo, 1.8 mmol of substrate and 2 mL of solvent (␣,␣,␣-trifluorotoluene or acetonitrile) were charged to the reactor and this was immersed in an oil bath heated to the desired temperature (35,55 or 70 • C) under magnetic stirring (1000 rpm). After 10 min, 2.75 mmol of oxidant (TBHP or H 2 O 2 ) was added to the preheated reaction mixture to give an initial Mo:Cy:oxidant molar ratio of 1:100:153.…”

“…[35,[38][39][40], imidazolium [36] or pyridinium derivatives [18,19,37]. In 1, the ditopic 4,4 -bipyridine molecule is bound to the metal centers through one of its pyridine aromatic rings.…”

“…0. 35 Table 1). The small dispersion within each family of internal polyhedral angles is clear structural evidence for the strong similarity of the two coordination environments in 1.…”

Bisguanidinium dinuclear oxodiperoxomolybdosulfate ion pair-catalyzed enantioselective sulfoxidation

“…( R , R )- 1b led to the formation of ent - 3a in 50% yield in 24 h with 31% ee (Fig. 6a, equation 2), demonstrating that two out of four peroxo moieties on ( R , R )- 1b are active oxygen donors, as two equivalent of active oxygen from ( R , R )- 1b are transferred to the sulfides53. The second oxygen transfer is slower and less enantioselective than the first.…”