17431-40-2Relevant academic research and scientific papers
Cis-dihydroxylation of alkenes with oxone catalyzed by iron complexes of a macrocyclic tetraaza ligand and reaction mechanism by ESI-MS spectrometry and DFT calculations
Chow, Toby Wai-Shan,Wong, Ella Lai-Ming,Guo, Zhen,Liu, Yungen,Huang, Jie-Sheng,Che, Chi-Ming
experimental part, p. 13229 - 13239 (2010/12/19)
[FeIII(L-N4Me2)Cl2]+ (1, L-N4Me2 = N,N′-dimethyl-2,11-diaza[3.3](2,6) pyridinophane) is an active catalyst for cis-dihydroxylation of various types of alkenes with oxone at room temperature using limiting amounts of alkene substrates. In the presence of 0.7 or 3.5 mol % of 1, reactions of electron-rich alkenes, including cyclooctene, styrenes, and linear alkenes, with oxone (2 equiv) for 5 min resulted in up to >99% substrate conversion and afforded cis-diol products in up to 67% yield, with cis-diol/epoxide molar ratio of up to 16.8:1. For electron-deficient alkenes including α,β-unsaturated esters and α,β-unsaturated ketones, their reactions with oxone (2 equiv) catalyzed by 1 (3.5 mol %) for 5 min afforded cis-diols in up to 99% yield with up to >99% substrate conversion. A large-scale cis-dihydroxylation of methyl cinnamate (9.7 g) with oxone (1 equiv) afforded the cis-diol product (8.4 g) in 84% yield with 85% substrate conversion. After catalysis, the L-N4Me2 ligand released due to demetalation can be reused to react with newly added Fe(ClO4)2?4H2O to generate an iron catalyst in situ, which could be used to restart the catalytic alkene cis-dihydroxylation. Mechanistic studies by ESI-MS, isotope labeling studies, and DFT calculations on the 1-catalyzed cis-dihydroxylation of dimethyl fumarate with oxone reveal possible involvement of cis-HO-Fe V O and/or cis-O FeV O species in the reaction; the cis-dihydroxylation reactions involving cis-HO-FeV O and cis-O FeV O species both proceed by a concerted but highly asynchronous mechanism, with that involving cis-HO-FeV O being more favorable due to a smaller activation barrier.
Osmium-Catalyzed Dihydroxylation of Olefins in Acidic Media: Old Process, New Tricks
Dupau, Philippe,Epple, Robert,Thomas, Allen A.,Fokin, Valery V.,Sharpless, K. Barry
, p. 421 - 433 (2007/10/03)
A screen of over 500 diversely functionalized additives in osmium-catalyzed dihydroxylation has uncovered that electron-deficient olefins are converted into the corresponding diols much more efficiently when the pH of the reaction medium is maintained on the acidic side. Further studies have identified citric acid as the additive of choice, for it allows preparation of very pure diols in yields generally exceeding 90%. As described here, a much wider range of olefin classes can now be successfully dihydroxylated. The process is experimentally simple, in most cases involving little more than dissolving the reactants in water or a waler/tertbutyl alcohol mixture, stirring them, and filtering off the pure diol product.
