13124-13-5Relevant articles and documents
Systematic Evaluation of 2-Arylazocarboxylates and 2-Arylazocarboxamides as Mitsunobu Reagents
Hirose, Daisuke,Gazvoda, Martin,Ko?mrlj, Janez,Taniguchi, Tsuyoshi
, p. 4712 - 4729 (2018/04/26)
2-Arylazocarboxylate and 2-arylazocarboxamide derivatives can serve as replacements of typical Mitsunobu reagents such as diethyl azodicarboxylate. A systematic investigation of the reactivity and physical properties of those azo compounds has revealed that they have an excellent ability as Mitsunobu reagents. These reagents show similar or superior reactivity as compared to the known azo reagents and are applicable to the broad scope of substrates. pKa and steric effects of substrates have been investigated, and the limitation of the Mitsunobu reaction can be overcome by choosing suitable reagents from the library of 2-arylazocarboxylate and 2-aryl azocarboxamide derivatives. Convenient recovery of azo reagents is available by one-pot iron-catalyzed aerobic oxidation, for example. SC-DSC analysis of representative 2-arylazocarboxylate and 2-arylazocarboxamide derivatives has shown high thermal stability, indicating that these azo reagents possess lower chemical hazard compared with typical azo reagents.
Advances and mechanistic insight on the catalytic Mitsunobu reaction using recyclable azo reagents
Hirose, Daisuke,Gazvoda, Martin,Ko?mrlj, Janez,Taniguchi, Tsuyoshi
, p. 5148 - 5159 (2016/07/29)
Ethyl 2-arylhydrazinecarboxylates can work as organocatalysts for Mitsunobu reactions because they provide ethyl 2-arylazocarboxylates through aerobic oxidation with a catalytic amount of iron phthalocyanine. First, ethyl 2-(3,4-dichlorophenyl)hydrazinecarboxylate has been identified as a potent catalyst, and the reactivity of the catalytic Mitsunobu reaction was improved through strict optimization of the reaction conditions. Investigation of the catalytic properties of ethyl 2-arylhydrazinecarboxylates and the corresponding azo forms led us to the discovery of a new catalyst, ethyl 2-(4-cyanophenyl)hydrazinecarboxylates, which expanded the scope of substrates. The mechanistic study of the Mitsunobu reaction with these new reagents strongly suggested the formation of betaine intermediates as in typical Mitsunobu reactions. The use of atmospheric oxygen as a sacrificial oxidative agent along with the iron catalyst is convenient and safe from the viewpoint of green chemistry. In addition, thermal analysis of the developed Mitsunobu reagents supports sufficient thermal stability compared with typical azo reagents such as diethyl azodicarboxylate (DEAD). The catalytic system realizes a substantial improvement of the Mitsunobu reaction and will be applicable to practical synthesis.
N-(Propargyl)diazenecarboxamides for 'click' conjugation and their 1,3-dipolar cycloadditions with azidoalkylamines in the presence of Cu(II)
Urankar, Damijana,Steinbücher, Miha,Kosjek, Jaka,Ko?mrlj, Janez
experimental part, p. 2602 - 2613 (2010/05/01)
Propargyl functionalized diazenes 1 were prepared by two different approaches and were examined as alkyne click components in copper-catalyzed azide-alkyne cycloadditions (CuAAC) with 2-(azidomethyl)pyridine 5a and four α-azido-ω-aminoalkanes C2-C5 (5b-e)
