<i>Lone</i>Selectivity of the Decatungstate-Sensitized Photooxidation of 1-Substituted Cycloalkenes
作者:Michael Orfanopoulos、Ioannis N. Lykakis
DOI:10.1055/s-2004-832803
日期:——
Decatungstate-sensitized oxidation of alkyl and phenyl substituted cycloalkenes in the presence of molecular oxygen shows a general preference for hydrogen abstraction on the congested side of the double bond.
Photoexcitation of contact charge-transfer (CCT) pairs of 1-arylcyclohexenes 1 (aryl: phenyl, 4-methylphenyl, and 4-methoxyphenyl) and oxygen in acetonitrile and benzene gave 1,2-epoxy-1-arylcyclohexanes 2 as major products together with 2-aryl-2-cyclohexen-1-ols and acetophenones 4. Similar irradiation of the CCT pairs in methanol/acetonitrile afforded mainly 2-aryl-2-methoxycyclohexanols instead of 2 and small amounts of 1-aryl-1-methoxycyclohexanes, 2-aryl-2-cyclohexen-1-ones, and 4. The formation of these products can be explained by photoinduced electron transfer in the excited CCT pairs generating radical cations of 1 and superoxide anions.
Hock; Siebert, Chemische Berichte, 1954, vol. 87, p. 554,557
作者:Hock、Siebert
DOI:——
日期:——
Selective C–H Allylic Oxygenation of Cycloalkenes and Terpenoids Photosensitized by [Cu(Xantphos)(neoc)]BF<sub>4</sub>
作者:Michael G. Kallitsakis、Dimitra K. Gioftsidou、Marina A. Tzani、Panagiotis A. Angaridis、Michael A. Terzidis、Ioannis N. Lykakis
DOI:10.1021/acs.joc.1c01591
日期:2021.10.1
We present herein for the first time the use of the [Cu(Xantphos)(neoc)]BF4 as a photocatalyst for the selective C–H allylic oxygenation of cycloalkenes into the corresponding allylic hydroperoxides or alcohols in the presence of molecular oxygen. The proposed methodology affords the products at good yields and has also been applied successfully to several bioactive terpenoids, such as geraniol, linalool