2345-27-9Relevant articles and documents
Hyperfine Structures of Doxyl-Labeled n-Alkyl Chains by NMR and EPR
Bales, Barney L.,Mareno, Donna,Harris, Francis L.
, p. 37 - 53 (1993)
The proton hyperfine coupling constants in a series of n-alkyl chains with a doxyl group attached at various points from the end of the chain have been measured by NMR and EPR spectroscopies.The hyperfine structure shows no further change when the attachment point is four or more carbon-carbon bonds from the end of the chain.The high resolution afforded by 500 MHz NMR reveals small magnetic inequivalencies in the chain methylene hyperfine coupling constants located at the same distance from the attachment point.Protons in the same chain methylene group are shown to have different hyperfine coupling constants while protons on different chain methylene groups, symmetrically placed with respect to attachment point, are the same, in every case except one.EPR spectra simulated from hyperfine coupling constants derived from NMR are in excellent agreement with experiment.Inhomogeneous EPR line broadening is found to be in excellent agreement with a previously derived universal hyperfine pattern (B.L.Bales, in "Biological Magnetic Resonance" (L.J.Berliner and J.Reuben, Eds.), Vol. 8, p. 77, Plenum, New York, 1989), so no new correction procedures are necessary.Strategies for selectively deuterating n-alkyl spin probes are developed and compared with some results taken from the literature.Deuterating the chain methylene groups two to three carbon-carbon bonds from the attachment point is necessary for the maximum gain in resolution and sensitivity.
MnO2as a terminal oxidant in Wacker oxidation of homoallyl alcohols and terminal olefins
Fernandes, Rodney A.,Ramakrishna, Gujjula V.,Bethi, Venkati
, p. 6115 - 6125 (2020/10/27)
Efficient and mild reaction conditions for Wacker-type oxidation of terminal olefins of less explored homoallyl alcohols to β-hydroxy-methyl ketones have been developed by using a Pd(ii) catalyst and MnO2 as a co-oxidant. The method involves mild reaction conditions and shows good functional group compatibility along with high regio- and chemoselectivity. While our earlier system of PdCl2/CrO3/HCl produced α,β-unsaturated ketones from homoallyl alcohols, the present method provided orthogonally the β-hydroxy-methyl ketones. No overoxidation or elimination of benzylic and/or β-hydroxy groups was observed. The method could be extended to the oxidation of simple terminal olefins as well, to methyl ketones, displaying its versatility. An application to the regioselective synthesis of gingerol is demonstrated.
Highly practical and efficient preparation of aldehydes and ketones from aerobic oxidation of alcohols with an inorganic-ligand supported iodine catalyst
Zhang, Mengqi,Zhai, Yongyan,Ru, Shi,Zang, Dejin,Han, Sheng,Yu, Han,Wei, Yongge
supporting information, p. 10164 - 10167 (2018/09/13)
Herein, we divulge an efficient protocol for aerobic oxidation of alcohols with an inorganic-ligand supported iodine catalyst, (NH4)5[IMo6O24]. The catalyst system is compatible with a wide range of groups and exhibits high selectivity, and shows excellent stability and reusability, thus serving as a potentially greener alternative to the classical transformations.
