4542-65-8Relevant academic research and scientific papers
Synthesis of (±)-brazilin using IBX
Huang, Yaodong,Zhang, Jinsong,Pettus, Thomas R. R.
, p. 5841 - 5844 (2007/10/03)
(Chemical Equation Presented) A short synthesis of (±)-brazilin is reported. This synthesis uses several interesting and underutilized transformations including a regioselective dirhodium-catalyzed aryl C-H insertion, a regioselective IBX phenol → o-quinone oxidation, a tautomerization of an o-quinone to a p-quinone methide, and an intramolecular aryl cyclization with a p-quinone methide.
Multiple Electron Oxidation of Phenols by an Oxo Complex of Ruthenium(IV)
Seok, Won K.,Meyer, Thomas J.
, p. 7358 - 7367 (2007/10/02)
The kinetics of oxidation of phenol and alkylated phenol derivatives by (2+) and (2+) (bpy is 2,2'-bipyridine and py is pyridine) to give the corresponding quinones have been studied in aqueous solution and in acetonitrile.The reactions are first order in both phenol and Ru(IV)=O(2+) or Ru(III)-OH(2+).They proceed via a detectable intermediate, which is a Ru(II) complex. 18O isotopic labeling experiments show that transfer of the oxo group from Ru(IV)=O(2+) to phenol is quantitative.The reactions are facile.With Ru(IV)=O(2+) as oxidant k(25 deg C, CH3CN) = 1.9 (+/-0.4) E2M-1s-1; with Ru(III)-OH(2+) as oxidant k(25 deg C, CH3CN) = 4.0 (+/-0.4) E1M-1s-1.On the basis of the rate laws, the magnitude of OH/OD and CH/CD kinetic isotope effects, and the 18O labeling results, the most reasonable mechanisms for oxidation of phenol by Ru(IV)=O(2+) appears to be electrophilic attack on the aromatic ring.For Ru(III)-OH(2+), oxidation appears to occur by CH/H atom transfer in CH3CN and OH/H atom transfer in water.
