Catalytic air oxidation of benzoin in the presence of dioxomolybdenum(VI) complexes with sulphur chelate ligands

Abstract

Catalytic air oxidation of benzoin t o benzil in N,N-dimethylformamide (dmf) occurred in the presence of [MoO,(cysS-OR),] [cysS-OR = S-deprotonated cysteine alkyl ester; R = M e (1) or Et (2)], [MOO,( S,CN Et , ), ] (3) or [ MoO,(cysS-N H C, , H, , ), ] (4) (cysS-NCH,,H,, = S-deprotonated cysteine n-decylamide), [Mo,O,(cysS-OMe),]( 5 ) , or [Mo,O,(S,CNEt,),] (6) with conversions of

Trans Influence of Oxo and Dithiolene Coordination in Oxidized Models of Molybdenum Oxidoreductase: Synthesis, Structures, and Properties of Q2[MoVIO2(1,2-benzenedithiolato)2] (Q = NEt4, PPh4) and Related Complexes

“…The stoichiometric reaction between 1a , 2 , or 3 and benzoin was examined in DMF at 29 °C. The reaction proceeds as in the following equation …”

“…Numerous model complexes for the oxidized state of these molybdenum enzymes have been synthesized using a (thiolato, N), (thiolato, thioketone), or (thiolato, thioether) ligand, e.g. [Mo VI O 2 (S,N-cys-OR) 2 ] (R = Me, Et), Mo VI O 2 (S 2 CNEt 2 ) 2 , [Mo VI O 2 (L) 2 ] (L = N,N ‘-dimethyl- N,N’ -bis(2-mercaptophenyl)ethylenediamine), Mo VI O 2 (L-NS 2 ) 2 (L-NS 2 = 2,6-bis(2,2-diphenyl-2-thioethyl)pyridinato), and Mo VI O 2 (dttd) (dttd = 2,3:8,9-dibenzo-1,4,7,10-tetrathiadecane), Many model reactions in the presence of dioxomolybdenum(VI) and monooxomolybdenum(IV) complexes have also been examined for the redox reaction of nitrate, triphenylphosphine, − benzoin, , amine N -oxide, , and dimethyl sulfoxide …”

Catalytic air and amine N-oxide oxidation of p-substituted benzoin by molybdenum(VI) complexes. Identification of the deactivation process by dioxygen

“…extremum at 510 nm as described previously. 6 The binuclear molybdenum(v) complex has also been found on reduction of (1) with triphenylph~sphine.~ The consumption of over 90% of 4,4'-dimethoxybenzoin in the 1 : 1 reaction indicates a two-electron transfer with formation of p-substituted benzil accompanied by 0x0 transfer from the dioxomolybdenum(vr) to the mono-oxomolybdenum(rv) complex. This is supported by the lack of an e.s.r.…”

Rapid Blue Bottle Experiment: Autoxidation of Benzoin Catalyzed by Redox Indicators

“…Oxidation of benzoin to benzil is a classical reaction reported elsewhere. − However, this is the first to consider the use of redox indicators as a catalyst in the autoxidation reaction that may be of interest to organic chemists for further investigation. Application of the classical blue bottle reaction as an oxygen sensor and reagent for high-resolution/millimeter-scale imaging may also benefit from this rapid formulation.…”