CAN-PROMOTED AND DDQ-PROMOTED OXIDATION OF ALKENYL SULFIDES
CAN-PROMOTED AND DDQ-PROMOTED OXIDATION OF ALKENYL SULFIDES
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DOI：
10.1021/jo00103a033
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发表时间：
1994-12-02
影响因子：
3.6
通讯作者：
NANNI, D
中科院分区：
文献类型：
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作者：
CAPELLA, L;MONTEVECCHI, PC;NANNI, D
乙烯基硫化物1与CAN在乙腈中在室温下反应，得到与硫杂丙环基自由基阳离子2B平衡的自由基阳离子2A。反应产物来自硝酸根离子对2A的硫原子或2B的三价碳的亲核攻击。最后一个反应可以通过硫化物部分的1，2-移位或置换进行。当α-亚甲基质子存在于2B中时，发生去质子化，导致烯丙基自由基，并最终导致异构的烯丙醇。1与DDQ在乙腈中的反应提供电荷转移复合物，然后两性离子电子转移（ET）复合物，当存在反式亚甲基质子时，该复合物可以通过分子内质子转移迅速发展。所得的硫-氧σ-络合物主要通过DDQH（2）的γ-消除或在δ-乙烯基碳上的亲核攻击，然后DDQH（-）的置换来负责反应产物。
Vinyl sulfides 1 react with CAN in acetonitrile at room temperature to give radical cations 2A in equilibrium with the thiiranyl radical cations 2B. The reaction products arise from nucleophilic attack of the nitrate counterion at either the sulfur atom of 2A or the trivalent carbon of 2B. The last reaction can proceed through 1,2-shift or displacement of the sulfide moiety. When alpha-methylenic protons are present in 2B, deprotonation occurs, leading to allyl radicals and, ultimately, to isomeric allyl alcohols. Reactions of 1 with DDQ in acetonitrile afford charge-transfer complexes and then zwitterionic electron-transfer (ET) complexes which can evolve rapidly through intramolecular proton transfer when trans methylenic protons are present. The resulting sulfur-oxygen sigma-complexes are responsible for the reaction products mainly through either gamma-elimination of DDQH(2) or nucleophilic attack at the delta-vinylic carbon followed by displacement of DDQH(-).