- A one-pot, two step synthesis of 2,2-disubstituted 1-nitroalkenes
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The reactions of ketones 1a-o, nitromethane 2, and a stoichiometric amount of piperidine 3a or ethylenediamine 3b in the presence of mercaptan 6a in THF or CH3CN solution give high yields of β-nitrosulfides 7a-o. The latter can be oxidized by 8
- Jang, Yeong-Jiunn,Lin, Wen-Wei,Shih, Yuh-Kuo,Liu, Ju-Tsung,Hwang, Ming-Hsing,Yao, Ching-Fa
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- An improved and easy method for the preparation of 2,2-disubstituted 1-nitroalkenes
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Reactions of ketones 1, nitromethane 2, and catalytic amount of piperidine 3 in the presence of mercaptan 6 generate β-nitroalkyl sulfides 7-9. At 0 °C and by the use of dichloromethane as solvent, β-nitroalkyl sulfides 7-9 can be oxidized by m-chloroperoxybenzoic acid (m-CPBA) 10 to generate β-nitroalkyl sulfoxides 11-13 and undergo elimination in carbon tetrachloride solution to produce medium to high yield of 2,2-disubstituted 1-nitroalkenes 5. The irreversibility of the synthetic mechanism not only can overcome the reversibility of the Henry reaction in the synthesis of 2,2-disubstituted 1-nitroalkenes 5 but also can generate the major products "exo-nitro olefins" 5c-e when cyclic ketones 1c-e were used. Under similar conditions, medium to high yield of 5-substituted-2-nitromethyl-2-phenylthioadamantane 17 also can be prepared from the reaction of 5-substituted-2-adamantanones 15, nitromethane 2, piperidine 3, thiophenol 6a. The intermediate 17 can be oxidized by m-CPBA 10 in dichloromethane solution and then undergo elimination at room temperature or can be dissolved in solvent, coated on silica gel, and then heated at 90-100 °C to generate 5-substituted-2-nitromethyleneadamantane 16.
- Lin,Jang,Wang,Liu,Hu,Wang,Yao
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p. 1984 - 1991
(2007/10/03)
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