<i>O</i>-Trifluoromethylation of<i>N</i>,<i>N</i>-Disubstituted Hydroxylamines with Hypervalent Iodine Reagents
作者:Václav Matoušek、Ewa Pietrasiak、Lukas Sigrist、Barbara Czarniecki、Antonio Togni
DOI:10.1002/ejoc.201402225
日期:2014.5
A mild trifluoromethylation reaction of N,N-disubstituted hydroxylamines that is tolerant towards a variety of functional groups, including nitriles, alcohols, ketones, esters, amides, imides, and nitrogen heterocycles, is reported. The key feature of this reaction is the activation of the CF3 reagent with either trimethylsilyl triflate or LiClO4 and partial or full deprotonation of the substrate with
据报道,N,N-二取代羟胺的温和三氟甲基化反应可以耐受多种官能团,包括腈、醇、酮、酯、酰胺、酰亚胺和氮杂环。该反应的关键特征是用三甲基甲硅烷基三氟甲磺酸酯或 LiClO4 活化 CF3 试剂,并用四甲基胍或二异丙基氨基锂使底物部分或完全去质子化。以高达 80% 的产率获得产品。初步机理研究表明,该反应遵循自由基途径,在该途径中,去质子化的羟胺和路易斯酸或布朗斯台德酸活化的 CF3 试剂参与单电子转移步骤,产生一对自由基,这些自由基重新组合以提供所需的产物。