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The Mitsunobu reaction can be efficiently used for the transformation of poly(ethylene glycol) (PEG) terminal OH group(s) into a variety of functions. In comparison to more classical approaches of PEG functionalization, the main advantage of the Mitsunobu reaction attains to the fact that in one step, with no detrimental effect on PEG integrity (e.g., chain cleavage). Here, its quantitative conversion is demonstrated into derivatives that, either directly or after deprotection, are amenable to (bio)conjugation reactions: azides (Huisgen cycloaddition), aldehydes, primary amines (Schiff base formation and reduction), thiols, and N‐oxymaleimide (Michael‐type addition). Therefore this reaction is proposed as a general tool for the preparation of functionalities for the purpose of PEGylation, and more generally for (bio)conjugation purposes.

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The Mitsunobu reaction is famous for its scope and power, but infamous for its separation headaches. Typically, the target product is enticed away from the reagent-derived byproducts by careful chromatography. The use of polymer-bound Mitsunobu reagents solves only half of the problem, because polymer-bound diethyl azodicarboxylate (DEAD) and phosphine reagents cannot be employed simultaneously. This article classifies, compares, and contrasts various emerging strategies for product isolation in Mitsunobu reactions. Because so many different strategies have been used, the Mitsunobu reaction is a microcosm for the new field of strategy level separations.  相似文献   

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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.  相似文献   

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Mitsunobu reaction of an alcohol ROH with a carboxylic acid, phthalimide, or N-hydroxyphthalimide (NuH) using DNAD (4) and (diphenylphosphino)polystyrene (11) gave the products RNu. Ring-opening metathetic polymerization of the side product DNADH(2) (3) using Cl(2)(Cy(3)P)(2)Ru=CHPh (13) and filtration, to remove poly(DNADH(2)), (diphenylphosphino)polystyrene 11, its oxide, and its adduct with excess DNAD, gave RNu (43-100%, 86-96% purity) without recourse to chromatography.  相似文献   

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Di-p-chlorobenzyl azodicarboxylate (DCAD) is introduced as a novel, stable, solid alternative to DEAD and DIAD for a variety of Mitsunobu couplings. DCAD/Ph(3)P-mediated reactions in CH(2)Cl(2) generate a readily separable hydrazine byproduct. [reaction: see text]  相似文献   

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A Mitsunobu reaction of trifluoroacetamide (TFA amide) and alcohols is used in a post‐polymerization modification process. The reaction is conducted on polystyrene (PSt) bearing 20 mol% TFA amide groups with 4‐methyl benzyl alcohol in the presence of a N,N,N′,N′‐tetramethylazodicarboxamide and tributylphosphine as mediators. The Mitsunobu reaction on polymer proceeds efficiently, as confirmed by the obvious precipitation generation during the reaction and the conversion of TFA amide moiety reached 88.6% confirmed by 19F NMR measurement, yielding PSt bearing tertiary TFA amide moieties. The obtained polymers featuring tertiary TFA amide moieties are deprotected in the presence of tetrabutylammonium hydroxide as a base to afford corresponding polymers featuring functionalized polyamine scaffolds with 92.5% conversion. In addition, the precise structural assignment is proven by synthesis and analysis of the model monomeric compounds and the respective model polymers.

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[formula: see text] The reaction of secondary and primary alcohols with highly fluorinated 3,4,5-tris(5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-heptadecafluorododecan- 1-yloxy)benzoic acid in the presence of Ph3P and DIAD in THF at room temperature (fluorous Mitsunobu) resulted in a simple, chromatography-free isolation protocol with excellent yields (83-96%).  相似文献   

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C-Glycosides were successfully prepared via dehydrative alkylation under Mitsunobu conditions, using substituted sulfonyl methanes as nucleophiles. The materials prepared were converted to useful C-glycoside intermediates. An application of this approach toward the synthesis of C-glycolipids is presented.  相似文献   

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The realization of the first polymer-on-polymer Mitsunobu reaction, in which a polymeric phosphine is used simultaneously with a polymeric azodicarboxylate, is reported. This strategy employs the use of soluble oligomers generated from ring-opening methathesis polymerization. 31P NMR analysis revealed that the two polymers were interacting to generate the Mitsunobu products. Application to several substrates, as well as comparison experiments with other polymeric reagents, is described.  相似文献   

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Mitsunobu反应研究进展   总被引:7,自引:0,他引:7  
Mitsunobu反应可以在温和的中性条件下形成C—O,C—N,C—S,C—C等键,因此被广泛地应用于各类天然产物的全合成或化合物的官能团转化,是一个比较重要的反应.简要介绍了近年来Mitsunobu反应的研究进展.  相似文献   

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A comparative study of the Mitsunobu reaction at C1 and C6 positions of mannose using bis(2,2,2-trifluoroethyl) malonate as nucleophile is disclosed. While C-alkylation was predominant at the C6 position, only O-alkylation occurred at the anomeric position of the carbohydrate. Some factors playing a role in the selectivity of the reaction are discussed and an inverse mechanism of the Mitsunobu reaction for the anomeric position is proposed.  相似文献   

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Kazutake Hagiya 《Tetrahedron》2009,65(31):6109-1096
Di-2-methoxyethyl azodicarboxylate (DMEAD) is prepared in 65% yield in two steps as a crystalline solid. Use of DMEAD in the Mitsunobu reaction of a variety of alcohols with pronucleophiles results in good yields of the products under sufficient stereospecificity of inversion, as conventional diisopropyl azodicarboxylate (DIAD) does. Isolation of the product is, however, much easier with DMEAD than that with DIAD, because the hydrazine produced from DMEAD is highly hydrophilic and is completely separable by a simple extraction into neutral water. Purification of the organic layer, after separation of the other by-product, triphenylphosphane oxide, by filtration, easily provides high purity of the product in a good yield. Concentration of the water layer yields the hydrazine, which can be reused for the preparation of DMEAD. One-step removal of the two by-products by the aqueous extraction was also possible when trimethylphosphane and DMEAD were employed.  相似文献   

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Reaction of hexa-N-Boc neomycin B with TPP and DIAD in toluene results in the formation of an epoxide in ring IV, not an aziridine or azetidine as previously reported.  相似文献   

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The alkylation of tetrazoles using Mitsunobu conditions and alcohols is reported. The methodology is superior to the base-promoted reaction with alkyl halides for the installation of a secondary alkyl group because it results in higher yields and facilitates the construction of chiral centers bearing tetrazole.  相似文献   

20.
Mechanistic study of the Mitsunobu reaction   总被引:3,自引:0,他引:3  
The Mitsunobu reaction occurs typically with inversion of configuration in secondary alcohol derivatives. In this paper, a mechanistic explanation for lactonizations of hindered alcohols under Mitsunobu conditions with retention is proposed. This involves the intermediacy of an acyloxyphosphonium salt followed by acyl transfer to the alcohol.  相似文献   

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