66542-65-2Relevant academic research and scientific papers
Chemoenzymatic synthesis of monocyclic arene oxides and arene hydrates from substituted benzene substrates
Boyd, Derek R.,Sharma, Narain D.,Ljubez, Vera,McGeehin, Peter K. M.,Stevenson, Paul J.,Blain, Marine,Allen, Christopher C. R.
, p. 3020 - 3029 (2013/07/26)
Enantiopure cis-dihydrodiol bacterial metabolites of substituted benzene substrates were used as precursors, in a chemoenzymatic synthesis of the corresponding benzene oxides and of a substituted oxepine, via dihydrobenzene oxide intermediates. A rapid total racemization of the substituted benzene 2,3-oxides was found to have occurred, via their oxepine valence tautomers, in accord with predictions and theoretical calculations. Reduction of a substituted arene oxide to yield a racemic arene hydrate was observed. Arene hydrates have also been synthesised, in enantiopure form, from the corresponding dihydroarene oxide or trans-bromoacetate precursors. Biotransformation of one arene hydrate enantiomer resulted in a toluene-dioxygenase catalysed cis-dihydroxylation to yield a benzene cis-triol metabolite. The Royal Society of Chemistry 2013.
Synthetic studies on the ingenane diterpenes. An improved entry into a trans-intrabridgehead system.
Rigby, James H,Bazin, Berangere,Meyer, J Hoyt,Mohammadi, Farahnaz
, p. 799 - 801 (2007/10/03)
[reaction: see text] The efficient construction of an ingenol intermediate exhibiting insideminus signoutside intrabridgehead stereochemistry is reported. The sequence features the net conversion of a cis-intrabridgehead compound into a highly strained trans-species via palladium-mediated isomerization of an allylic epoxide followed by a low-temperature alkoxide-accelerated 1,5-hydrogen migration.
Is benzene oxide homoaromatic? A microcalorimetric study
Jia,Brandt,Thibblin
, p. 10147 - 10152 (2007/10/03)
Rate constants and heats of reaction for the aromatization of benzene oxide (1) and the acid-catalyzed aromatization of benzene hydrate (2) in highly aqueous solution giving phenol and benzene, respectively, have been measured by heat-flow microcalorimetry. The measured heat of reaction of benzene oxide, ΔH = -57.0 kcal mol-1, is much larger than that of benzene hydrate, ΔH = -38.7 kcal mol-1, despite an unusually low reactivity of benzene oxide, rate ratio 0.08. The measured enthalpies agree with those calculated using the B3LYP hybrid functional corrected with solvation energies derived from semiempirical AM1/SM2 calculations. Comparison with the measured enthalpies of the corresponding reactions of the structurally related 1,3-cyclohexadiene oxide (3) and 2-cyclohexenol (4) of ΔH = -24.9 kcal mol-1 (includes a small calculated correction of - 1.2 kcal mol-1) and ΔH ～ 0 kcal mol-1, respectively, gives a smaller aromatization energy for the benzene oxide than for the benzene hydrate reaction (ΔΔΔH = 6.6 kcal mol-l). This suggests that benzene oxide is unusually stabilized by a significant amount of homoaromatization as has been proposed previously (J. Am. Chem. Soc. 1993, 115, 5458). This unusual stability accounts for more than half of the ～107 times lower than expected reactivity of benzene oxide toward acid-catalyzed isomerization. The rest is suggested to originate from an unusually high energy of the carbocation-forming transition state.
Frontier electronic structure in gas-phase epoxy and hydroxy cyclohexenes by means of photoelectron and electron transmission spectroscopies
Scagnolari, Francesco,Modelli, Alberto,Bottoni, Andrea,Jones, Derek,Lazzari, Dario
, p. 1447 - 1453 (2007/10/03)
Ionisation energy (Ei) and electron affinity (Ea) values in benzene oxide, benzene hydrate, the corresponding monoenes and other j related molecules have been measured by means of UV photoelectron spectroscopy and electron transmission spectroscopy. The valence filled levels do not show evidence for strong σco-π or oxygen lone pair-π mixing in the alcohols nor in the epoxides. Although the energy perturbations, caused by the hydroxy and epoxy substituents, to adjacent filled π orbitals are small, the electron transmission spectra show that the empty π* orbitals are affected to very different extents, the epoxy substituent producing a sizeable electron affinity increase. This finding indicates the occurrence of strong interaction between the empty πz.ast; orbitals and low-energy empty σ orbitals localised at the three-membered cycle. The experimental data have been compared with the orbital energies predicted by ab initio 3-21G calculations.
