Metal-Free 2,2,6,6-Tetramethylpiperidin-1-yloxy Radical (TEMPO) Catalyzed Aerobic Oxidation of Hydroxylamines and Alkoxyamines to Oximes and Oxime Ethers
作者:Sebastian Wertz、Armido Studer
DOI:10.1002/hlca.201200175
日期:2012.10
TEMPO‐Mediated oxidation of hydroxylamines (=hydroxyamines) and alkoxyamines to the corresponding oxime derivatives is reported (TEMPO=2,2,6,6‐tetramethylpiperidin‐1‐yloxy radical; Scheme 2). These environmentally benign oxidations proceed in good to excellent yields (Table 1). For alkoxyamines, oxidation to the corresponding oxime ethers can be performed by using dioxygen as a terminal oxidant in
据报道,TEMPO介导的羟胺(=羟胺)和烷氧基胺氧化为相应的肟衍生物(TEMPO = 2,2,6,6-四甲基哌啶-1-基氧基;方案2)。这些对环境无害的氧化以良好至极好的收率进行(表1)。对于烷氧基胺,可以在5-10 mol%的TEMPO或其4取代的衍生物作为催化剂的情况下,使用双氧作为末端氧化剂,氧化成相应的肟醚(流程3和表2)。重要的是,苄基溴可通过亲核取代,然后由TEMPO介导的氧化,通过原位烷氧基胺形成直接转化为肟醚(方案4和表3)。