90246-32-5Relevant academic research and scientific papers
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.
The "fully Catalytic System" in Mitsunobu Reaction Has Not Been Realized Yet
Hirose, Daisuke,Gazvoda, Martin,Ko?mrlj, Janez,Taniguchi, Tsuyoshi
supporting information, p. 4036 - 4039 (2016/08/30)
An investigation of the recently reported "fully catalytic Mitsunobu reaction" using catalytic amounts of a phosphine reagent and an azo reagent has shown that although benzyl 4-nitrobenzoate is formed under the fully catalytic conditions, the same result is obtained if the hydrazine catalyst is omitted, indicating that this is not a Mitsunobu reaction. In addition, when the reaction between (-)-ethyl lactate and 4-nitrobenzoic acid was carried out using the "fully catalytic" method, the corresponding ester was formed but in very low yield and with predominant retention of configuration. Unfortunately, the system catalytic in phosphine reagent is incompatible with that in the azo reagent.
Mitsunobu Reactions Catalytic in Phosphine and a Fully Catalytic System
Buonomo, Joseph A.,Aldrich, Courtney C.
supporting information, p. 13041 - 13044 (2015/11/02)
The Mitsunobu reaction is renowned for its mild reaction conditions and broad substrate tolerance, but has limited utility in process chemistry and industrial applications due to poor atom economy and the generation of stoichiometric phosphine oxide and hydrazine by-products that complicate purification. A catalytic Mitsunobu reaction using innocuous reagents to recycle these by-products would overcome both of these shortcomings. Herein we report a protocol that is catalytic in phosphine (1-phenylphospholane) employing phenylsilane to recycle the catalyst. Integration of this phosphine catalytic cycle with Taniguchi's azocarboxylate catalytic system provided the first fully catalytic Mitsunobu reaction. Make it catalytic: A catalytic Mitsunobu reaction using innocuous reagents to recycle the stoichiometric phosphine oxide and hydrazine by-products was developed. The reported method is catalytic in 1-phenylphospholane and uses phenylsilane to recycle the catalyst. Integration of this phosphine catalytic cycle with Taniguchi's azocarboxylate catalytic system provided the first fully catalytic Mitsunobu reaction.
Recyclable mitsunobu reagents: Catalytic mitsunobu reactions with an iron catalyst and atmospheric oxygen
Hirose, Daisuke,Taniguchi, Tsuyoshi,Ishibashi, Hiroyuki
supporting information, p. 4613 - 4617 (2013/06/04)
Aerobic recycling: A catalytic amount of a hydrazine reagent is sufficient to promote Mitsunobu reactions in the presence of triphenylphosphine, an iron catalyst, and air. The active form of the catalyst, an azo species, can be readily generated by iron-c
Monomer-on-monomer (MoM) Mitsunobu reaction: Facile purification utilizing surface-initiated sequestration
Maity, Pradip K.,Rolfe, Alan,Samarakoon, Thiwanka B.,Faisal, Saqib,Kurtz, Ryan D.,Long, Toby R.,Schaetz, Alexander,Flynn, Daniel L.,Grass, Robert N.,Stark, Wendelin J.,Reiser, Oliver,Hanson, Paul R.
supporting information; experimental part, p. 8 - 10 (2011/02/27)
A monomer-on-monomer (MoM) Mitsunobu reaction utilizing norbornenyl-tagged (Nb-tagged) reagents is reported, whereby purification was rapidly achieved by employing ring-opening metathesis polymerization, which was initiated by any of three methods utilizi
Organocatalytic mitsunobu reactions with 3,5-dinitrobenzoic acid
But, Tracy Yuen Sze,Lu, Jinni,Toy, Patrick H.
supporting information; experimental part, p. 1115 - 1117 (2010/06/19)
A second generation procedure for organocatalytic Mitsunobu reactions using 3,5-dinitrobenzoic acid as the pro-nucleophile has been developed. The increased acidity of this acid compared to 4-nitrobenzoic acid, which was used in the original procedure, allowed for higher isolated yields of the desired products and eliminated formation of undesired acetate byproducts. Georg Thieme Verlag Stuttgart - New York.
Organocatalytic Mitsunobu reactions
But, Tracy Yuen Sze,Toy, Patrick H.
, p. 9636 - 9637 (2007/10/03)
A catalytic Mitsunobu reaction system is described in which the azo reagent is used as an organocatalyst and iodosobenzene diacetate is used as the stoichiometric oxidant. In this system, iodosobenzene diacetate oxidizes the formed hydrazine byproduct to regenerate the azo reagent. Yields obtained in the catalytic reactions using a variety of carboxylic acids and alcohols were slightly lower than those obtained from corresponding stoichiometric reactions. Both primary and secondary alcohols can be used as substrates in this reaction system, with the secondary alcohols affording products with inverted stereochemistry at the carbinol center. Copyright
Tetraarylphosphonium salts as solubility-control groups: Phosphonium-supported triphenylphosphine and azodicarboxylate reagents
Poupon, Jean-Christophe,Boezio, Alessandro A.,Charette, Andre B.
, p. 1415 - 1420 (2007/10/03)
(Chemical Equation Presented) Predictable solubilities! Reagents supported on a tetraarylphosphonium group have solubilities that can be predicted. The reagents and their by-products can be readily removed, recovered, and recycled after reaction by a precipitation/filtration sequence initiated by the addition of a low-polarity solvent, such as diethyl ether. Furthermore, the supported reagents are robust and exhibit reactivities similar to their parent compounds.
