2,2-雙取代-1-硝基烯之簡易製備法

The easy method for the preparation of 2,2-disubstituted-1-nitroalkenes

王曄(Wang Yeh)

指導教授 ： 姚清發

國立臺灣師範大學/理學院/化學系/碩士(1999年)

摘要

酮類（ketones）1a-e可與硝基甲烷（nitromethane）2在催化量的piperidine 3存在下與trapping reagents 4（thiophenol 4a、α-toluenthiol 4b或allyl mercaptan 4c）反應產生β-nitroalkylsulfides（5a-d、6a-e或7a-e）。於0 ℃條件下用CH2Cl2為溶劑，m-chloroperoxybenzoic acid (m-CPBA) 8 可將β-nitroalkylsulfides（5a-d、6a-e或7a-e）氧化成β-nitroalkylsulfoxides（9a-d、10a-e或11a-e），然後再用CCl4為溶劑在迴流的條件下脫去PhSOH產生2,2-雙取代-1-硝基烯類12a-e。其反應機構之不可逆性除了可克服亨利反應（Henry reaction）中在合成2,2-雙取代-1-硝基烯類12a-b時之不實用性(可逆反應)外，亦可由環酮類合成環外硝基烯類12c-e。由此簡易改良法可將12a-e產率提昇至中等至高產率，在類似的反應條件下5-substituted adamantan-2-ones 16a-f和2及催化量的3亦可得到5-substituted-2-nitromethylene-admantanes 18a-f。同時發現β-nitroalkylsulfoxides（9b、10c、10d、11c或11e）在鹼性水溶液處理下亦可得到12b-e，但產率約在25-65%之間，比上述之熱解反應之產率稍低。

關鍵字

2,2-雙取代-1-硝基烯類 ； 亨利反應

並列摘要

Ketones 1a-e、nitromethane 2 can react with the trapping reagents 4（thiophenol 4a, α-toluenthiol 4b or allyl mercaptan 4c）in the presence of catalytic amount of piperidine 3 to produce β-nitroalkylsulfides（5a-d, 6a-e or 7a-e）. By the use of CH2Cl2 as solvent and at 0 ℃, β-nitroalkylsulfides（5a-d, 6a-e or 7a-e）can be oxidized by m-chloroperoxybenzoic acid (m-CPBA) 8 to produce β-nitroalkyl sulfoxides（9a-d、10a-e or 11a-e）and subsequently elimination to produce 2,2-disubstituted 1-nitroalkenes 12a-e. The irreversibility of the synthetic mechanism not only could overcome the impracticability of the Henry reaction in the synthesis of 2,2-disubstituted 1-nitroalkenes 12a-b but also could produce the major product "exo-nitroolefins" 12c-e when cyclic ketones were used. By using this improved and easy methodology to prepare 2,2-disubstituted-1-nitroalkenes 12a-e, the yields of the products are medium to high. Under similar reaction conditions 5-substituted adamantan-2-ones 16a-f can also react with 2 in the presence of catalytic amount of piperidine 3 to produce 5-substituted-2-nitromethylene-admantanes 18a-f. 12b-e Also can be produced when β-nitroalkylsulfoxides（9b, 10c, 10d, 11c , and 11e）are treated with dilute aqueous basic solution, but the yields are lower than those of pyrolysis condition.

並列關鍵字

2,2-disubstituted 1-nitroalkenes ； Henry reaction

參考文獻

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