Maity Anirban, Studer Armido
Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Corrensstraße 40 48149 Munster Germany
Chem Sci. 2023 Jun 23;14(28):7675-7680. doi: 10.1039/d3sc02544f. eCollection 2023 Jul 19.
1,2-Aminoxyalkylation of alkenes with alkyl iodides and TEMPONa in combination with an aryldiazonium salt as an XAT mediator is reported. Various primary, secondary and tertiary alkyl iodides engage as C-radical precursors in the 1,2-aminoxyalkylation with electrophilic alkenes as radical acceptors. The product alkoxyamines are readily transformed to the corresponding alcohols or ketones upon reduction or oxidation, respectively. Mechanistic investigations reveal that aryl radicals, generated through SET-reduction of the aryl diazonium salt with TEMPONa, engage in XAT from unactivated alkyl halides to give alkyl radicals that can add to alkenes. Trapping of the adduct radicals with TEMPO provides the 1,2-aminoxyalkylation products. Transition metals are not required for these transformations that are conducted under mild conditions. Perfluoroalkyl halides directly react with TEMPONa and an aryldiazonium salt as XAT-mediator is not required for alkene 1,2-aminoxyperfluoroalkylation.
报道了在作为XAT介质的芳基重氮盐存在下,烯烃与烷基碘和TEMPONa进行1,2-氨氧基烷基化反应。各种伯、仲和叔烷基碘作为碳自由基前体,与亲电烯烃作为自由基受体发生1,2-氨氧基烷基化反应。产物烷氧基胺分别在还原或氧化后容易转化为相应的醇或酮。机理研究表明,芳基重氮盐与TEMPONa通过单电子转移还原产生的芳基自由基,从不活泼的卤代烃中发生XAT反应生成烷基自由基,该烷基自由基可加成到烯烃上。用TEMPO捕获加合自由基可得到1,2-氨氧基烷基化产物。这些反应在温和条件下进行,不需要过渡金属。全氟烷基卤化物直接与TEMPONa反应,烯烃的1,2-氨氧基全氟烷基化反应不需要芳基重氮盐作为XAT介质。