549-03-1Relevant articles and documents
Electrophilic hydroxylation of aromatics in superacids
Jacquesy, Jean-Claude,Berrier, Christian,Gesson, Jean-Pierre,Jouannetaud, Marie-Paule
, p. 658 - 664 (2007/10/02)
In superacids, protonated hydrogen peroxide hydroxylates various aromatics to give phenols.The substrates react in their protonated forms with the electrophile H3O2+.Phenols (and their methyl ethers), anilines, indolines, indoles, aromatic aldehydes and ketones are hydroxylated without any degradation; protonation protects the functional group(s) that are normally sensitive to oxidants.Electrophilic hydroxylation of polyfunctional natural products (vincadifformine, estrane derivatives) has been succesfully performed with H2O2/HF/SbF5. - Keywords: superacids / hydroxylation / hydrogen peroxide / aromatics / phenols / indoles
HYDROXYLATION DE L'ESTRONE ET DE SON ACETATE PAR LE PEROXYDE D'HYDROGENE EN MILIEU SUPERACIDE
Berrier, C.,Jacquesy, J. C.,Jouannetaud, M. P.
, p. 5135 - 5142 (2007/10/02)
Estrone 1a and its acetate 1b react with hydrogen peroxide in SbF5-HF to give hydroxylated compounds.The formation of the dienone 2 can be accounted for by reaction of the electrophile H3O2+ on the neutral substrate, whereas formation of compound 3b implies electrophilic attack on the protonated ester 1b.Higher acidity favours rearrangement of the resulting ion 9 to yield, through a spiro intermediate, the ester 4b.Under the reaction conditions esters 3b and 4b are slowly converted into the corresponding phenols 3a and 4a.