ChemInform Abstract: WASSERSTOFFPEROXID UND ‐DERIVATE ALS OXIDATIONSMITTEL IN DER ORGANISCHEN CHEMIE

The (Schiff base)vanadium(V) Complex Catalyzed Oxidation of Bromide − A New Method for the in situ Generation of Bromine and Its Application in the Synthesis of Functionalized Cyclic Ethers

“…In detail, the use of 1 mol % of methioninol-derived vanadium() complex 5c led to a 3.8-fold increase in the rate of product formation, which was improved to a factor of 4.5 in relation to the uncatalyzed reaction if 10 mol % of 5c was used as catalyst. It is worth mentioning that 1 mol % of VO(acac) 2 , if applied as catalyst under such conditions, led to the formation of a Table 2. Screening for reactivity: application of vanadium() catalysts 5aϪg for the oxidation of bromide in the presence of 1-phenyl-4-penten-1-ol (6) [a] Preparative scale (0.5 mmol).…”

“…[11] These enzymes are able to catalyze the oxidation of, for example, Br Ϫ with H 2 O 2 under physiological conditions. [12] In particular, a vanadium()-dependent bromoperoxidase (VBPO) from the brown algae Ascophyllum nodosum has attracted attention, [10a] since its turnover of Br Ϫ at pH ϭ 6.5 in the presence of the primary oxidant H 2 O 2 exceeds that of the powerful reagent VO(O 2 ) 2 Ϫ at pH ϭ 1. [13] Although the exact nature of the electrophilic halogenating reagent in such transformations remains the subject of ongoing discussions, [14] the fundamentals of this chemistry are of notable synthetic interest, since they combine the benefits of on-site generation of Br 2 with that of transition metal based catalysis.…”

“…The on-site generation of molecular bromine, [1] either in a separate ex situ free halogen reactor [2] or in solution (i.e. in situ), [3] avoids the necessity to store Br 2 in larger quantities in a laboratory or at a production site.…”

(Schiff‐base)vanadium(V) Complex‐Catalyzed Oxidations of Substituted Bis(homoallylic) Alcohols − Stereoselective Synthesis of Functionalized Tetrahydrofurans

“…1 (Figure 1), has received considerable attention. [6,7] In the last few years, the most significant progress in this field of research has originated from transition metal catalyzed oxidations [8] Ϫ transformations which utilize active oxygen compounds, such as hydrogen peroxide, [9,10] peroxo compounds, [10,11] or molecular oxygen [12] as primary oxidants. In spite of their high oxidation potentials, these reagents, if used alone, are sur- Figure 1.…”