37563-30-7Relevant academic research and scientific papers
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
Greb, Marco,Hartung, Jens,Koehler, Franz,Spehar, Kristina,Kluge, Ralph,Csuk, Rene
, p. 3799 - 3812 (2007/10/03)
(Schiff base)vanadium(v) complexes 5 with tridentate imine auxiliaries served as catalysts for the oxidation of Br with tert-butyl hydroperoxide (TBHP) in nonaqueous solvents. This reaction has been applied for the conversion of substituted 4-penten-1-ols into 5-exo-bromo-cyclized products, including a diastereomerically pure heterocyclic precursor used in a synthesis of the all-trans-configured 2,3,4,5-substituted tetrahydrofuran 2-epi-magnosalicin. Treatment of co-substituted bis(homoallylic) alcohols with the reagent combination of pyHBr, TBHP, and a vanadium(v) catalyst 5 afforded 6-endo-cyclized products, i.e. brominated tetrahydropyrans, as major compounds. The results from 51V NMR, ESI-MS, and supporting reactivity- selectivity studies indicated that the mechanism of the new bromination reaction consists of vanadium-dependent and vanadium-independent steps. A (Schiff base)vanadium(v) compound 5 is required for activation of TBHP via in situ formation of the corresponding tert-butylperoxy complex. This reagent oxidizes Br-, which under the reaction conditions provides Br2 as the active brominating reagent. The molecular bromine generated thus is released into the solution at a steady rate and serves as a reagent for the synthesis of β-brominated cyclic ethers from bis(homoallylic) alcohols in a second, vanadium-independent step. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
HETEROCYCLISATIONS INDUCED BY THALLIUM(III) ACETATE. EFFECT OF VARYING THE INTERNAL NUCLEOPHILE
Michael, Joseph P.,Nkwelo, Mluleki M.
, p. 2549 - 2560 (2007/10/02)
The stereochemistry of the 2,5-disubstituted tetrahydrofuran formed on treating 5-methyl-1-phenylhex-4-en-1-ol (6) with thallium(III) acetate in appropriate solvents has been established as trans by means of nuclear Overhauser experiments.Replacement of t
