Electrochemical Fluorocyclization of N-Allylcarboxamides to 2-Oxazolines by Hypervalent Iodine Mediator
摘要:
A resource saving protocol for the synthesis of 5-fluoromethyl-2-oxazolines by using electrochemistry has been realized. Thereby, a hypervalent iodine species I(III) is generated by anodic oxidation in the presence of Et3N center dot 5HF and mediates the cyclization of N-allylcarboxamide to 5-fluoromethyl-2-oxazoline. This method allows application to various substrates furnishing the 2-oxazolines with yields up to 68%. The protocol is easy to conduct under constant current conditions offering a sustainable alternative over conventional reagent-based pathways.
Electrochemical oxidative radical cascade cyclization of olefinic amides and thiophenols towards the synthesis of sulfurated benzoxazines, oxazolines and iminoisobenzofurans
containing N and O are important structures in pharmaceuticals, agrochemicals and functional molecules. The synthesis of these compounds usually requires complex substrates and harsh reaction conditions. Herein, we introduce a mild and efficient electrochemical oxidative strategy to construct benzoxazines, oxazolines and iminoisobenzofurans without the requirement of a transition-metal catalyst and an
含 N 和 O 的杂环是药物、农用化学品和功能分子中的重要结构。这些化合物的合成通常需要复杂的底物和苛刻的反应条件。在此,我们引入了一种温和有效的电化学氧化策略来构建苯并恶嗪、恶唑啉和亚氨基异苯并呋喃,而无需过渡金属催化剂和外部氧化剂。在一个简单的未分开的细胞中,各种烯酰胺和苯硫酚/二硒化物反应生成 69 个硫醇化和硒化杂环的例子,产率高达 83%。此外,这种自由基级联反应为一步构建 C-S/C-Se 和 C-O 键提供了一种简便的方法。
Structure-Dependent Nickel-Catalysed Transposition of N-Allylamides to E- or Z-Enamides
of a carbon–carbon double bond of N-allyl and N-homoallyl amides is described. While the transposition of acyclic amides gave very high Z-selectivity of the enamides, corresponding cyclic N-allyl amides led exclusively to the E-configured products. Thereby, we realised a stereodivergent approach to enamides that is dependent on the structure of the amide substituents. When homoallylic substrates are
The annulation reactions of N-allylbenzamides with N-sulfonylaminopyridinium salts were developed under metal-free photoinduced mild conditions. Substituent-controlled sulfonaminoarylation and sulfonaminooxylation of benzamides were realized: N-allylbenzamides lead to benzosultams, while N-(2-phenylallyl)benzamides give sulfonamidylated oxazoline derivatives. Control experiments indicated that those
Sterically Demanding Oxidative Amidation of α-Substituted Malononitriles with Amines Using O<sub>2</sub>
作者:Jing Li、Martin J. Lear、Yujiro Hayashi
DOI:10.1002/anie.201603399
日期:2016.7.25
An efficient amidation method between readily available 1,1-dicyanoalkanes and either chiral or nonchiral amines was realized simply with molecular oxygen and a carbonate base. This oxidative protocol can be applied to both sterically and electronically challenging substrates in a highly chemoselective, practical, and rapid manner. The use of cyclopropyl and thioether substrates support the radical
Electrochemical Fluorocyclization of <i>N</i>-Allylcarboxamides to 2-Oxazolines by Hypervalent Iodine Mediator
作者:John D. Haupt、Michael Berger、Siegfried R. Waldvogel
DOI:10.1021/acs.orglett.8b03682
日期:2019.1.4
A resource saving protocol for the synthesis of 5-fluoromethyl-2-oxazolines by using electrochemistry has been realized. Thereby, a hypervalent iodine species I(III) is generated by anodic oxidation in the presence of Et3N center dot 5HF and mediates the cyclization of N-allylcarboxamide to 5-fluoromethyl-2-oxazoline. This method allows application to various substrates furnishing the 2-oxazolines with yields up to 68%. The protocol is easy to conduct under constant current conditions offering a sustainable alternative over conventional reagent-based pathways.