Hypervalent-Iodine-Mediated Formation of Epoxides from Carbon(sp2)-Carbon(sp3) Single Bonds.

Title Hypervalent-Iodine-Mediated Formation of Epoxides from Carbon(sp2)-Carbon(sp3) Single Bonds.
Authors S. Jiang; T.S. Yan; Y.C. Han; L.Q. Cui; X.S. Xue; C. Zhang
Journal J Org Chem
DOI 10.1021/acs.joc.7b00883
Abstract

We have developed an efficient method for direct formation of epoxide groups from carbon(sp2)-carbon(sp3) single bonds of ?-keto esters; the reaction is mediated by the water-soluble hypervalent iodine(V) reagent AIBX (5-trimethylammonio-1,3-dioxo-1,3-dihydro-1?5-benzo[d][1,2]iodoxol-1-ol anion). On the basis of the results of density functional theory calculations and experimental studies, we propose that the reaction proceeds by a two-stage mechanism involving dehydrogenation of the ?-keto ester substrates and epoxidation of the resulting enone intermediates. The rate-limiting step is abstraction of the ?'-C-H (calculated free energy of activation, 24.5 kcal/mol).

Citation S. Jiang; T.S. Yan; Y.C. Han; L.Q. Cui; X.S. Xue; C. Zhang.Hypervalent-Iodine-Mediated Formation of Epoxides from Carbon(sp2)-Carbon(sp3) Single Bonds.. J Org Chem. 2017. doi:10.1021/acs.joc.7b00883

Related Elements

Carbon

See more Carbon products. Carbon (atomic symbol: C, atomic number: 6) is a Block P, Group 14, Period 2 element. Carbon Bohr ModelThe number of electrons in each of Carbon's shells is 2, 4 and its electron configuration is [He]2s2 2p2. In its elemental form, carbon can take various physical forms (known as allotropes) based on the type of bonds between carbon atoms; the most well known allotropes are diamond, graphite, amorphous carbon, glassy carbon, and nanostructured forms such as carbon nanotubes, fullerenes, and nanofibers . Carbon is at the same time one of the softest (as graphite) and hardest (as diamond) materials found in nature. It is the 15th most abundant element in the Earth's crust, and the fourth most abundant element (by mass) in the universe after hydrogen, helium, and oxygen. Carbon was discovered by the Egyptians and Sumerians circa 3750 BC. It was first recognized as an element by Antoine Lavoisier in 1789.

Iodine

See more Iodine products. Iodine (atomic symbol: I, atomic number: 53) is a Block P, Group 17, Period 5 element with an atomic radius of 126.90447. The number of electrons in each of Iodine's shells is 2, 8, 18, 18, 7 and its electron configuration is [Kr] 4d10 5s2 5p5. The iodine atom has a radius of 140 pm and a Van der Waals radius of 198 pm. In its elemental form, iodine has a lustrous metallic gray appearance as a solid and a violet appearance as a gas or liquid solution. Elemental IodineIodine forms compounds with many elements, but is less active than the other halogens. It dissolves readily in chloroform, carbon tetrachloride, or carbon disulfide. Iodine compounds are important in organic chemistry and very useful in the field of medicine. Iodine was discovered and first isolated by Bernard Courtois in 1811. The name Iodine is derived from the Greek word "iodes" meaning violet.

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