utilization of decomposition products of PFECAs. We report herein a new series of deoxyfluorination reagents featuring OCF2 functional groups derived from certain PFECAs. Alkyl fluorides were generated from various alcohols in ≤97% yield by these novelreagents. The mechanistic experiment verified in situgeneration of carbonic difluoride (COF2).
Kinetics of the reactions of laser-flash photolytically generated carbenium ions with alkyl and silyl enol ethers. Comparison with the reactivity toward alkenes, allylsilanes and alcohols
作者:Joerg Bartl、Steen Steenken、Herbert Mayr
DOI:10.1021/ja00020a038
日期:1991.9
corresponding alkyl-substituted ethylenes. The reactivities of structurally analogous alkyl and silylenolethers differ by less than 1 order of magnitude. In sharp contrast to the situation previously observed for the reactions of benzhydryl cations with alkenes, the nucleophilic reactivities of the enolethers correlate with their ionization potentials and not with the stabilities of the carbenium ions
二芳基碳鎓离子(二苯甲基阳离子)是在 20 OC 的乙腈溶液中通过 20-11 秒激光脉冲 (248 nm) 从二芳基甲基氯生成的。它们与 n 和 w 亲核试剂(阴离子、醇、水、烯烃、烯丙基硅烷、烷基和甲硅烷基烯醇醚)反应的二级速率常数是通过在可变亲核试剂浓度下监测 UV-vis 瞬变的衰减来确定的。由于碳鎓离子与溶剂乙腈和光杂解中产生的氯离子同时发生反应,因此只能通过这种方法研究反应性亲核试剂 (k2 > 106-107 L mol-' sI)。观察到的最大 k2 值为 -2 X 1Olo 与阴离子反应和 (2-4) X IO8, mol-' sI 与中性亲核试剂反应。烷氧基取代的乙烯的反应性比相应的烷基取代的乙烯高 300-1 倍。结构相似的烷基和甲硅烷基烯醇醚的反应性相差不到 1 个数量级。与之前观察到的二苯甲基阳离子与烯烃反应的情况形成鲜明对比的是,烯醇醚的亲核反应性与其电离电位相
Tetramethylfluoroformamidinium Hexafluorophosphate (TFFH) as a Mild Deoxofluorination Reagent
作者:Pascal Dubé、Gabriel Bellavance、Bao Nguyen
DOI:10.1055/s-0031-1290336
日期:2012.3
air-stable peptide coupling reagent TFFH (tetramethylfluoroformamidinium hexafluorophosphate) was found to activate a variety of alcohols towards deoxofluorination. These conditions are compatible with carbonyl functional groups thus offering interesting possibilities for the application to sensitive molecules. deoxofluorination - fluoroformamidinium -fluoride- TFFH -fluorination
Transition metal-free cross-dehydrogenative arylation of unactivated benzylic C–H bonds
作者:Andrew R. A. Spencer、Rachel Grainger、Adyasha Panigrahi、Thomas J. Lepper、Katarzyna Bentkowska、Igor Larrosa
DOI:10.1039/d0cc06212j
日期:——
cross-dehydrogenative arylation of benzylic C–H bonds with arenes provides straightforward access to synthetically useful 1,1-diarylmethanes, from readily available starting materials. Current approaches suffer from limited substrate scope, requirement for large excesses of alkyl arene and/or non-trivial reaction set up. We report a transition metal-free cross-dehydrogenative arylation of benzylic C–H bonds using