Oxidative addition reactions of ?-alkenyl nitronate anions
Oxidative addition reactions of ?-alkenyl nitronate anions
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α-烯基硝基阴离子的氧化加成反应
DOI：
10.1039/p19930002099
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
D. Crosby
中科院分区：
文献类型：
--
作者：
W. Bowman;David S. Brown;C. Burns;D. Crosby
当使用六氰基铁(III)钾作为氧化剂时，阴离子被氧化加成到硝基阴离子上，生成α-取代的硝基烷烃。硝基阴离子的氧化产生中间体硝基烷基自由基，其与阴离子加成得到中间体α-取代的硝基烷自由基阴离子，其进一步氧化产生α-取代的硝基烷烃。使用的硝基阴离子衍生自5-硝基己-1-烯、6-硝基庚-1-烯、内-5-硝基-外-6-苯基双环[2.2.1]庚-2-烯和1-(双环[2.2.1]庚-5-烯-内-2-基)-2-硝基丙烷。中间体α-硝基烷基自由基经历阴离子加成形成自由基阴离子的速度比分子内环化到ω-烯烃上的速度更快。当氧化在不存在添加阴离子的情况下进行时，衍生自1-(双环[2.2.1]庚-5-烯-内-2基)-2-硝基丙烷的α-硝基烷基发生环化。阴离子（硫氰酸根、苯亚磺酸根、4-氯苯硫酸根和亚硝酸根）添加到源自内-5-硝基-外-6-苯基双环[2.2.1]庚-2-烯的α-硝基烷基上，是从受阻较小的外面立体选择性地发生的。将4-氯苯硫醇氧化加成至内-5-硝基-外-6-苯基双环[2.2.1]庚-2-烯的硝基酯上，通过将硫基自由基加成至烯烃上，产生不寻常的环化。
Anions are oxidatively added to nitronate anions to yield α-substituted nitroalkanes when potassium hexacyanoferrate(III) is used as oxidant. Oxidation of nitronate anions yields intermediate anitroalkyl radicals, which undergo addition by anions to give intermediate α-substituted nitroalkane radical anions, which are further oxidised to yield the α-substituted nitroalkanes. The nitronate anions used are derived from 5-nitrohex-1-ene, 6-nitrohept-1-ene, endo-5-nitro-exo-6-phenylbicyclo[2.2.1 ]hept-2-ene, and 1-(bicyclo[2.2.1 ]hept-5-en-endo-2-yl)-2-nitropropane. The intermediate α-nitroalkyl radicals underwent addition of anions to form radical anions faster than intramolecular cyclisation onto the ω-alkenes. The α-nitroalkyl radical derived from 1-(bicyclo[2.2.1 ]hept-5-en-endo-2yl)-2-nitropropane underwent cyclisation when the oxidation was carried out in the absence of an added anion. The addition of anions (thiocyanate, benzenesulfinate, 4-chlorobenzenethiolate, and nitrite) to the α-nitroalkyl radicals derived from endo-5-nitro-exo-6-phenylbicyclo[2.2.1]hept-2-ene occurred stereoselectively from the less hindered exo face. Oxidative addition of 4-chlorobenzenethiolate to the nitronate from endo-5-nitro-exo-6-phenylbicyclo[2.2.1]hept-2-ene gave an unusual cyclisation via addition of a thiyl radical to the alkene.