- Substrate promiscuity of ortho-naphthoquinone catalyst: Catalytic aerobic amine oxidation protocols to deaminative cross-coupling and n-nitrosation
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ortho-Naphthoquinone-based organocatalysts have been identified as versatile aerobic oxidation catalysts. Primary amines were readily cross-coupled with primary nitroalkanes via deaminative pathway to give nitroalkene derivatives in good to excellent yields. Secondary and tertiary amines were inert to ortho-naphthoquinone catalysts; however, secondary nitroalkanes were readily converted by ortho-naphthoquinone catalysts to the corresponding nitrite species that in situ oxidized the amines to the corresponding N-nitroso compounds. Without using harsh oxidants in a stoichiometric amount, the present catalytic aerobic oxidation protocol utilizes the substrate promiscuity feature to provide a facile access to amine oxidation products under mild reaction conditions.
- Kim, Hun Young,Oh, Kyungsoo,Si, Tengda
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p. 9216 - 9221
(2019/10/08)
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- Mass spectrometric investigations on phenylacetic acid derivatives, IV: Loss of ortho-substituents from ionized phenyl-2-propanones upon electron impact
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In the gas phase, the phenyl-2-propanone molecules 2a-4a lose upon electron impact chloro-, bromo-, and iodo-radicals specifically at the orthopOsition of the phenyl group giving rise to strong (M-Hal.)+-ions (70/12 eV; 1st and 2nd FFR) of identical structure as confirmed by their MIKE-CAD-spectra. The daughter ions at m/z 133 from o-chlorophenyl-2-propanone (2a) and 2,2-dimethyl-2,3-dihydro[b]furane (11) are structurally similar but not identical (similarity index 99.8). The collisionally activated (2nd FFR) (M-Br.)+-ions from o-bromophenyl-2-propanone (3a) and 1-bromo-1-phenyl-2-propanone (12) produce virtually congruent spectra. The most impOrtant subsequent fragmentation of the (M-Hal-)+-ions from 2a-4a is the loss of CO which incorporates the C-atom of the carbonyl group exclusively (13C labelling). Mechanistic aspects of the fragmentation sequences are discussed (Figs. 5 and 8).
- Striegel,Mayer,Wiegrebe,Schlunegger,Siegrist,Aebi
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p. 751 - 760
(2007/10/02)
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- Porphyrin synthesis from nitrocompounds
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A new porphyrin synthesis starting from nitroalkenes or their equivalents is described. For example, octaethylporphyrin, coproporphyrin, porphyrin-1,2,3,4,5,6,7,8 octapropionic acid, and 2,7,12,17 tetraarylporphyrin are prepared in good yield from readily available materials such as 1-nitropropane, nitroethane, nitromethane, and aldehydes.
- Ono, Noboru,Kawamura, Hisayuki,Bougauchi, Masahiro,Maruyama, Kazuhiro
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p. 7483 - 7496
(2007/10/02)
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