Stereoselective Radical Azidooxygenation of Alkenes
作者:Bo Zhang、Armido Studer
DOI:10.1021/ol402106x
日期:2013.9.6
Radical azidooxygenation of various alkenes is described. A readily prepared N3-iodine(III) reagent acts as a clean N3-radical precursor. Radical generation is achieved with TEMPONa acting as a mild organic reducing reagent. The C-radical generated after N3-radical addition is efficiently trapped by in situ generated TEMPO. Yields are good to excellent, and for cyclic systems azidooxygenation occurs
A novel method for selective generation of aryl radicals from diaryliodonium salts and iodanylidene malonates with sodium 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPONa) as a single‐electron transfer (SET) reducing reagent is described. In the presence of various alkenes, aryl radicals formed after SET‐reduction of hypervalent iodine compounds undergo alkene addition and the adduct radicals that are
Transition-Metal-Free Oxyarylation of Alkenes with Aryl Diazonium Salts and TEMPONa
作者:Marcel Hartmann、Yi Li、Armido Studer
DOI:10.1021/ja307638u
日期:2012.10.10
The reaction of readily available TEMPONa with aryl diazonium salts allows for clean generation of the corresponding aryl radicals along with TEMPO. Aryl radical addition to alkenes with subsequent TEMPO trapping provides the corresponding oxyarylation products in good to excellent yields. These experimentally easy to conduct transformations occur in the absence of any transition metal under mild conditions
容易获得的 TEMPONa 与芳基重氮盐的反应允许与 TEMPO 一起清洁产生相应的芳基。芳基自由基加成到烯烃并随后进行 TEMPO 捕集,以良好至极好的产率提供相应的氧芳基化产物。这些实验上容易进行的转变在温和条件下不存在任何过渡金属的情况下发生,并且该过程显示出广泛的官能团兼容性。
Transition-Metal-Free Trifluoromethylaminoxylation of Alkenes
作者:Yi Li、Armido Studer
DOI:10.1002/anie.201202623
日期:2012.8.13
No transition metal! Fluorinated hypervalent‐iodine reagents react with TEMPONa in the presence of an alkene under mild conditions to give the corresponding perfluoroalkylaminoxylation products. These radical addition/trapping reactions occur with high stereoselectivity using commercially available reagents, and the product alkoxyamines are readily transformed into the corresponding alcohols.
Determination of rate constants for trifluoromethyl radical addition to various alkenes via a practical method
作者:M. Hartmann、Y. Li、A. Studer
DOI:10.1039/c5ob02210j
日期:——
CF3-addition product formed, which is readily determined by 19F-NMR spectroscopy, rateconstants for trifluoromethyl radicaladdition to the π-acceptor can be calculated. The practical method is also applicable to measure rateconstants for the addition of other perfluoroalkyl radicals to alkenes as documented for CF3CF2-radical addition reactions.