112711-99-6Relevant academic research and scientific papers
Nature of the Epoxidizing Species Generated by Reaction of Alkyl Hydroperoxides with Iron (III) Porphyrins. Oxidations of cis-Stilbene and (Z)-1,2-Bis(trans-2,trans-3-diphenylcyclopropyl)ethene byt-BuOOH in the Presence of [meso-Tetrakis(2,4,6-trimethylphenyl)porphinato]-, [meso-Tetrakis(2,6-dichlorophenyl)porphinato]-, and [meso-Tetrakis(2,6-dibromophenyl)porphinato]iron(III) Cloride
He, Gong-Xin,Bruice, Thomas C.
, p. 2747 - 2753 (2007/10/02)
The mechanism of the of the oxidation of alkenes by t-BuOOH in the of iron(III) tetraphenylporphyrins has been explored (CH2Cl2 solvent). The alkenes, cis-stilbene and (Z)-1,2,-bis(trans-2,trans-3diphenylcyclopropyl)ethene (1-Z), have been chosen because they serve as traps for radical intermediates. The substituted iron(III) tetraphenylporphyrin catalysts employed are [meso-tetrakis(2,4,6-trimethiytphenyl)porphinato]iron(III) chloride ((TMP)FeIII(Cl)), [meso-tetrakis(2,6-dichlorophenyl)porphinato]iron(III) chloride ((Cl8TPP)FeIII(Cl)), and [meso-tetrakis(2,6-dibromophenyl)porphinato]iron(III) chloride ((Br8TPP)FeIII(Cl)). In experiments, azobisisobutyronitrile (AIBN) was as a chain for the of the oxidation of the alkenes byt-BuOOH. Oxidation of cis-stilbene with iron(III) as as a (trace), a [1H NMR, MS(CI)] the structure PhCH[OO(t-Bu)]CH[O(t-Bu)]Ph. We the are of t-BuOO., rather than (+.Porph)FeIV(O), with cis-stilbene. Oxidation of 1-Z iron(III) porphyrins as catalysts provides A (1H NMR, MS(CI), FT-IR) as the major product . Other products are B (whose structure has not determined), which contains intact one of the two trans-2,trans-3-diphenylcyclopropane groups, trans-2,trans-3-diphenylcyclopropanecarboxaldehyde, and deoxybenzoin. In A, one cyclopropyl group has a undergone a cyclopropylcarbinyl to homoallylcarbinyl radical rearrangement (CPCRR) while the other has remained intact. The major product A arises from initial combination of t-BuOO. with 1-Z followed by CPCRR. Reaction sequences are suggested. The cis-epoxide of 1-Z (2-c) is in 3,2% yield when (Cl8T- PP)FeIII (Cl) is catalyst. A trace of 2-c is with (TMP)FeIII(a), but 2-c not be with (TMP)FeIII(Cl), but 2-c could not be detected with (Br8TPP)FeIII(Cl). The cis-epoxide 2-c most likely arises from the concerted reaction of 1-Z with the iron(IV)-oxo porphyrin π cation radical (+.Cl8TPP)FeIv(O)(Cl). The species (+.Cl8TPP)FeVI(O)(Cl) may be the direct of of reaction of (Cl8TPP)FeIII(Cl) with t-BuOOH in a mechanism that involves heterolytic O-O Alternatively, (+.Cl8TPP)FeIV(O)(Cl) may arise via (Cl8TPP)FeIII(Cl) + t-BuOOH → (Cl8TPP)FeIV(O) + t-BuO' followed by oxidation of (Cl8TPP)FeIV(O)FeIV by t-BuOOH (or other). It is pointed out that (Cl8TPP)FeIV(O), unlike (TMP)FeIV(O), accumulates in relatively high concentration and that t-BuOOH is present at 0.3 M.
