Stereoelectronic effect in equilibration and methoxy exchange of cyclic methoxysulfonium salts
作者:István Jalsovszky、Ferenc Ruff、Árpád Kucsman
DOI:10.1016/s0040-4020(01)81923-2
日期:1993.1
methanol yields an equilibrium mixture of cis- and trans-methoxysulfonium chlorides. The corresponding methoxysulfonium tetrafluoroborates prepared from sulfoxides by O-alkylation show equilibration and methoxy exchange in methanol containing chlorideions. The rate constants have been determined by 1H NMR measurements, and an SN(Ad+E) mechanism is proposed for these reactions. Both the greater thermodynamic
次氯酸叔丁酯在甲醇中的烷基硫杂环戊烷和烷基硫烷的转化产生顺式和反式甲氧基ulf氯化物的平衡混合物。由亚砜通过O-烷基化制备的相应的四氟硼酸甲氧基s在含有氯离子的甲醇中显示出平衡和甲氧基交换。已通过1 H NMR测量确定了速率常数,并为这些反应提出了一种S N(Ad + E)机制。顺式异构体的更大的热力学稳定性和反式类似物的更大的反应性都可以通过σ(CH)-σ *的立体电子效应来解释(SX)类型,用XOMe或Cl。
Akhtar, M. Naseem; Boyd, Derek R.; Neill, John D., Journal of the Chemical Society. Perkin transactions I, 1980, p. 1693 - 1699
作者:Akhtar, M. Naseem、Boyd, Derek R.、Neill, John D.、Jerina, Donald M.
DOI:——
日期:——
Reactions of Sulfinylated Radicals. Stereoselectivity in Six-Membered Rings
作者:Philippe Rehaud
DOI:10.1002/hlca.19910740620
日期:1991.9.18
deuteration of six-membered cyclic sulfinylatedradicals were investigated. For this purpose, radicals with the predefined conformations I and II were generated from 2-(phenylselenenyl)thiacyclo-hexane-1-oxide derivatives 7–10 (Scheme). Steric effects were insufficient to account for all the observed selectivities. The participation of stereoelectronic effects are envisaged to explain the stereoselective axial