55549-01-4Relevant academic research and scientific papers
Copper-catalyzed aerobic C-C bond cleavage of lactols with N-hydroxy phthalimide for synthesis of lactones
Tnay, Ya Lin,Chiba, Shunsuke
supporting information, p. 873 - 877 (2015/04/14)
The transformation of cyclic hemiacetals (lactols) into lactones has been achieved by Cu-catalyzed aerobic C-C bond cleavage in the presence of N-hydroxy phthalimide (NHPI). The present process is composed of a multistep sequence including a) formation of exo-cyclic enol ethers by dehydration; b) addition of phthalimide N-oxyl radical to the enol ethers followed by trapping of the resulting C-radicals with molecular oxygen to form peroxy radicals; c) reductive generation of oxy radicals and subsequent β-radical fragmentation to generate lactones.
Direct synthesis of 1,4-diols from alkenes by iron-catalyzed aerobic hydration and C-H hydroxylation
Hashimoto, Takuma,Hirose, Daisuke,Taniguchi, Tsuyoshi
supporting information, p. 2730 - 2734 (2014/03/21)
Various 1,4-diols are easily accessible from alkenes through iron-catalyzed aerobic hydration. The reaction system consists of a user-friendly iron phthalocyanine complex, sodium borohydride, and molecular oxygen. Furthermore, the effect of additional ligands on the iron complex was examined for a model reaction. The second hydroxy group is installed by direct C(sp3)-H oxygenation, which is based on a [1,5] hydrogen shift process of a transient alkoxy radical that is formed by formal hydration of the olefin. One more hydroxy group: A method for the synthesis of 1,4-diols from simple alkenes has been developed. This unusual transformation entails an iron-catalyzed aerobic hydration and is achieved with convenient reagents, such as molecular oxygen. The formation of an intermediary alkoxy radical, which undergoes a [1,5] hydrogen shift, is likely to be essential for C(sp3)-H hydroxylation. Pc=phthalocyanine.
Copper-catalyzed aerobic aliphatic C-H oxygenation with hydroperoxides
Too, Pei Chui,Tnay, Ya Lin,Chiba, Shunsuke
supporting information, p. 1217 - 1225 (2013/07/26)
We report herein Cu-catalyzed aerobic oxygenation of aliphatic C-H bonds with hydroperoxides, which proceeds by 1,5-H radical shift of putative oxygen-centered radicals (O-radicals) derived from hydroperoxides followed by trapping of the resulting carboncentered radicals with molecular oxygen.
An efficient oxidative lactonization of 1,4-diols catalyzed by Cp*Ru(PN) complexes
Ito, Masato,Osaku, Akihide,Shiibashi, Akira,Ikariya, Takao
, p. 1821 - 1824 (2008/02/02)
An efficient oxidative lactonization of 1,4-diols in acetone is accomplished by the well-defined ruthenium catalyst, whose bifunctional nature underlies the high efficiency as well as unique chemo- and regioselectivity of the reaction which provides a rapid access to γ-butyrolactones including flavor lactones hinokinin, and muricatacin.
Oxygen activation by metal complexes and alkyl hydroperoxides. Applications of mechanistic probes to explore the role of alkoxyl radicals in alkane functionalization
MacFaul, Philip A.,Arends, Isabella W. C. E.,Ingold, Keith U.,Wayner, Danial D. M.
, p. 135 - 146 (2007/10/03)
The mechanism of the oxidation of cycloalkanes by tertiary alkyl hydroperoxides catalysed by iron(III) dichlorotris(2-pyridylmethyl)amine IIICl2(TPA)>+ and by the acetate bridged (μ-oxo) di-iron complex III(TPA)2O(OAc)>3+ has been investigated.Product studies do not support oxidation via a high valent iron-oxo intermediate (formally FeV=O), but are consistent with a mechanism involving hydrogen atom abstraction from the alkane by alkoxyl radicals derived from the hydroperoxide.In the presence of a large excess of tert-butyl hydroperoxide, the oxidation of cyclohexane yields cyclohexanone, cyclohexanol and tert-butylcyclohexyl peroxide in more than stoichiometric amounts and, in the case of the mono-iron catalyst, one equivalent of cyclohexyl choride.Replacement of Me3COOH by hydroperoxides, which could yield tert-alkoxyl radicals having much shorter lifetimes than the tert-butoxyl radical prevents oxidation of the cycloalkane.The products obtained with these hydroperoxide mechanistic probes are those derived from the fast unimolecular reactions (generally β-scissions) of the corresponding alkoxyl radicals.The inapplicability of dimethyl sulfide as a mechanistically diagnostic trap for the putative FeV=O intermediate and the value of di-tert-butyl hyponitrite as a non-iron-based source of tert-butoxyl radicals are discussed.
Electron-transfer-induced reductive cleavage of phthalans: Reactivity and synthetic applications
Azzena, Ugo,Demartis, Salvatore,Melloni, Giovanni
, p. 4913 - 4919 (2007/10/03)
The behavior of phthalan (1a) was investigated under conditions of electron transfer from alkali metals in aprotic solvents. Reaction with lithium in the presence of a catalytic amount of naphthalene in THF led to the reductive cleavage of an arylmethyl carbon-oxygen bond, with formation of a stable dilithium compound. Trapping of this intermediate with several electrophiles (alkyl halides, carbonyl derivatives, CO2) was successful. The extension of this procedure to several substituted phthalans (1b-i) was investigated, and the regiochemistry as well as the synthetic usefulness of these reactions are discussed.
The Role of Alkoxyl Radicals in Gif (GoAggv) Chemistry
Snelgrove, Darren W.,MacFaul, Philip A.,Ingold, Keith U.,Wayner, Danial D. M.
, p. 823 - 826 (2007/10/03)
The oxidation of cyclooctane using tert-alkyl hydroperoxides under GoAggv conditions has been examined using selected alkyl hydroperoxides as mechanistic probes. The results indicate that the products are formed by alkoxyl radical-induced reactions, there being no need to invoke any chemistry involving high valent iron-oxo species.
