Noncovalent Attachment of Nucleotides by Fluorous?Fluorous Interactions: Application to a Simple Purification Principle for Synthetic DNA Fragments

We report a highly efficient noncovalent immobilization of DNA fragments on surfaces by fluorous? fluorous interactions. The principle was applied to a simple and straightforward purification protocol for synthetic DNA. The method is completely compatible with standard solid‐phase synthesis of DNA.     

Highly Efficient Dinitration of Aromatic Compounds in Fluorous Media using Ytterbium Perfluorooctanesulfonate and Perfluorooctanesulfonic Acid as Catalysts

Ytterbium perfluorooctanesulfonate [Yb(OPf)₃] and perfluorooctanesulfonic acid [PfOH] catalyze the highly efficient dinitration of toluene, benzene, benzyl chloride, and chlorobenzene in fluorous media. Notably the process produces almost no waste acid, as opposed to the traditional case. The fluorous phase‐containing catalyst could be easily and efficiently recovered for reuse by simple phase separation.     

Microwave synthesis and fluorous purification of 4-(tetrathienyl)butyric acid for self-assembled monolayer semiconductor applications

Microwave-promoted synthesis and fluorous purification procedures have been employed successfully to generate 4-(tetrathienyl)butyric acid rapidly. Initially, a fluorous tag 1H,1H-perfluorooctylamine was tethered to 4-(thienyl)butyric acid via an amide traceless linkage. Subsequent, sequential α-bromination and Stille cross-coupling reactions with 2-(tributylstannyl)thiophene grew the fluorous-tagged 4-(oligothienyl)butyric acid efficiently. Each synthetic transformation was followed by a fluorous-solid phase extraction procedure to isolate the fluorous-tagged compound intermediate in excellent yield. Finally, the fluorous tag was cleaved by microwave-promoted saponification of the amide bond to liberate the desired 4-(tetrathienyl)butyric acid.     

Metal bis(perfluorooctanesulfonyl)amides as highly efficient Lewis acid catalysts for fluorous biphase organic reactions

In fluorous biphase system, metal bis(perfluorooctanesulfonyl)amides are better Lewis acid catalysts than the analogous triflates toward either transesterifications, or direct esterifications, or Friedel-Crafts acylations or Baeyer-Villiger oxidations. These catalysts are selectively soluble in lower fluorous phase and can be recovered simply by phase separation. Furthermore, these catalysts can be reused without decrease of activity in most cases.     

在氟溶剂中的绿色酯化反应

以全氟壬烯为氟溶剂, 对物质的量的羧酸和醇的酯化反应进行了系统研究. 在不移走生成物的条件下, 酯与全氟壬烯能形成氟两相体系而脱离酯化可逆反应体系, 促进反应平衡右移, 使收率提高10%～47%, 氟溶剂通过冷却和简单的相分离, 就可回收并直接套用. 氟溶剂在有机相中的损失小. 在氟溶剂中的酯化反应回流温度有较大幅度的下降.     

Increasing fluorous partition coefficients by solvent tuning

Low partition coefficients of fluorous components have been a persistent problem in liquid-liquid separations using perfluoroalkanes as the fluorous phase. Solvent tuning of both the nonfluorous and the fluorous phase dramatically enhances the partitioning of light or polar fluorous molecules into the fluorous liquid phase, while minimally effecting partition coefficients of nonfluorous molecules. These findings suggest an expanded scope for liquid-based separations in fluorous biphasic catalysis, fluorous-tagged reagents, fluorous-supported oligomer synthesis, and related areas. [reaction: see text]     

全氟辛基磺酰亚胺稀土(Ⅲ)催化氟两相Friedel-Crafts烷基化反应

制备了全氟辛基磺酰亚胺盐(M[N(SO2C8F17)2]n,n:3,4),并用于催化氟两相烷基化反应。考察了催化剂种类、反应时间、反应温度和催化剂用量对烷基化反应的影响,同时探讨了Yb[N(SO2C8F17)2]3对烷基化试剂摩尔比为0.2%时,催化烷基化试剂与不同芳烃的反应,表明Yb[N(SO2C8F17)2]3是一种有效的烷基化催化剂。含有催化剂的氟相通过简单的相分离后,可回收利用。氟相重复使用5次,其催化活性降低不大。     

Fluorous-phase soluble polymeric supports

Fluorous phase soluble polymer supports derived from fluoroacrylate polymers are described. N-Acryloxysuccinimide-containing fluoroacrylate polymers were readily prepared from commercially available monomers. The activated acrylates so prepared were then converted into chelating and non-chelating ligands by amidation of the N-acryloxysuccinimide active ester residues. Phosphine ligands attached to these supports were used to prepare neutral and cationic rhodium(I) hydrogenation catalysts as well as palladium(0) catalysts. Similar substitution of pendant active ester groups to form hydroxamic acid ligands for metal sequestration is also feasible. Liquid/liquid extraction readily separated, recycled and reused these polymer-bound ligands and catalysts. While fluorous phase solubility could be attained with polymers containing only heptafluorobutyryl groups, selective solubility in a fluorous phase in contact with an organic phase was only seen with fluoroacrylates that contained larger fluorinated ester groups.     

Reverse fluorous solid-phase extraction: a new technique for rapid separation of fluorous compounds

Fluorous-tagged compounds can rapidly be separated from organic (non-tagged) compounds by the new separation technique of reverse fluorous solid-phase extraction (r-fspe). In a reversal of the roles of solid and liquid phases in standard fluorous spe, a mixture is charged to a polar solid phase (standard silica gel) and then eluted with a fluorous solvent or solvent mixture. The organic components of the mixture are retained, while the fluorous components pass. [structure: see text]     

Synthesis and properties of a novel family of fluorous triphenylphosphine derivatives

A novel approach to the preparation of perfluorotail-functionalized triarylphosphines using a p-silyl substituent as the branching point has been developed. This approach enabled the attachment of between three and nine perfluorotails per phosphorus atom, resulting in the production of highly fluorous tris[p-(1H,1H,2H, 2H-perfluoroalkylsilyl)aryl]phosphines, P[C(6)H(4)-p-SiMe(3)(-)(n)()(CH(2)CH(2)C(x)()F(2)(x)()(+1))(n)()](3) (n = 1, 2, 3; x = 6, 8), containing between 50 and 67 wt % fluorine. (31)P NMR studies indicate that the phosphorus atoms, and consequently the sigma-donor and pi-acceptor properties of these phosphines, are not influenced by the electron-withdrawing perfluoroalkyltails. The fluorous triarylphosphines are readily soluble in fluorous solvents and display fluorous phase preference in several fluorous biphasic systems. The phase partitioning of these fluorous ligands, as well as their donor properties, is discussed in relation to their potential for fluorous biphasic catalyst separation.     

An alternative and facile purification procedure of amidation and esterification reactions using a medium fluorous Mukaiyama reagent

A convenient methodology for the separation of a fluorous by-product using fluorous chemistry is described. A Mukaiyama coupling reagent bearing a medium fluorous tag, between 40% and 60% fluorine by weight, can be effectively separated from non-fluorous components by increasing the water content of the crude reaction mixture and subsequent filtration. Additional fluorous solid phase extraction is not necessary.     

Novel fluorous prolinol as a pre-catalyst for catalytic asymmetric borane reduction of various ketones

Novel prolinol carrying two perfluorohexylethyl groups at the α-position was prepared from l-proline as a starting chiral substrate. Catalytic asymmetric reduction of various ketones, including mono-, di-, and trifluoromethylated acetophenones, using fluorous oxazaborolidines derived from fluorous prolinol afforded the corresponding alcohols in good to excellent yields and with high enantioselectivities (up to 93.2% ee). The fluorous prolinol was recovered without any fluorous solvents or silica gel by simply cooling the organic phase and filtration.     

Combining lipase-catalyzed enantiomer-selective acylation with fluorous phase labeling: a new method for the resolution of racemic alcohols

Lipase-catalyzed acylation of racemic alcohols with a highly fluorinated acyl donor allows their kinetic resolution accompanied by the simultaneous enantiomer-selective fluorous phase labeling. Both the tagged and the untagged enantiomer can be separated without chromatography by a very efficient partition between a fluorous and an organic phase. The method has been successfully applied to the resolution of typically racemic secondary alcohols of low molecular weight. The fluorous label can be recovered quantitatively.     

A practical fluorous benzylidene acetal protecting group for a quick synthesis of disaccharides

A new fluorous benzylidene acetal protecting group was regioselectively introduced into carbohydrates, deprotected under acidic conditions, and reused. Oligosaccharides were synthesized via regioselective conversion of the fluorous acetal group to the benzyl group by traditional reaction conditions. The fluorous compounds were easily separated from non-fluorous by-products by fluorous solid phase extraction.     

Fluorous synthesis of allylic fluorides: C-F bond formation as the detagging process

A novel fluorous tagging-detagging strategy has been developed featuring a fluorination as the detagging process; fluorous allylsilanes were prepared by cross-metathesis and subsequently subjected to electrophilic fluorodesilylation; Selectfluor was used as the detagging reagent; the resulting allylic fluorides were successfully purified by fluorous solid phase extraction.     

Stereoselective conjugate radical additions: application of a fluorous oxazolidinone chiral auxiliary for efficient tin removal

[reaction: see text] A series of asymmetric free-radical-mediated intermolecular conjugate additions using a fluorous oxazolidinone chiral auxiliary has been completed. The fluorous auxiliary facilitated product isolation using fluorous solid phase extractions (FSPE), effectively removing excess organic and organometallic reagents. Parallel reactions carried out with a similar but nonfluorous norephedrine-derived oxazolidinone demonstrated the superior stereoselectivity and purification obtainable with the fluorous chiral auxiliary.     

Separation of "light fluorous" reagents and catalysts by fluorous solid-phase extraction: synthesis and study of a family of triarylphosphines bearing linear and branched fluorous tags

Practical syntheses of new triarylphosphines bearing both linear and branched fluorous tags (Rf) are reported. The phosphines have one, two, or all three aryl rings bearing fluorous tags: (Ph)(3)(-)(n)()P(C(6)H(4)(CH(2))(m)()Rf)(n)(). Fluorous-organic partition coefficients have been measured and the retention properties of both the phosphines and the derived phosphine oxides on fluorous reverse phase silica have been studied. While applications relying on liquid-liquid extractive separations of these phosphines may be limited to those bearing three fluorous chains, the technique of solid phase extraction should be broadly applicable to phosphines, phosphine oxides, and derived metal complexes. A parallel platinum-catalyzed allylation of aldehydes with fluorous allyl stannanes illustrates the usefulness of the new fluorous ligands in small-scale synthesis.     

Use of fluorous chemistry in the solubilization and phase transfer of nanocrystals, nanorods, and nanotubes

Fluorous chemistry, involving the use of a fluorous label for the functionalization of a substrate and a fluorous solvent for extraction of the functionalized substrate, is shown to be effective in solubilizing gold and CdSe nanoparticles in a fluorous medium, through phase transfer from an aqueous or a hydrocarbon medium. While these nanoparticles were functionalized with a fluorous thiol, single-walled carbon nanotubes and ZnO nanorods could be solubilized in a fluorous medium by reacting them with a fluorous amine. Fluorous chemistry enables the solubilization of the nanostructures in the most nonpolar liquid medium possible.     

Structure assignment of lagunapyrone B by fluorous mixture synthesis of four candidate stereoisomers

Techniques of fluorous mixture synthesis have been used to make four candidate stereoisomers for the natural product lagunapyrone B. A quasiracemic mixture of vinyl iodides whose component configurations at C19-21 were encoded by fluorous silyl groups was fused to a central fragment by a Negishi coupling. A separate quasiracemic mixture of pyrone fragments whose component configurations at C6,7 were also encoded by fluorous silyl groups was synthesized and demixed. Stille coupling of the resulting pure quasienantiomers with the quasiracemic mixture provided two quasi-diastereomeric samples, which were demixed and detagged to provide all four lagunapyrone B stereoisomers. Lagunapyrone was assigned the 6R,7S,19S,20S,21R configuration by comparison of optical rotations.     

Disassembly via an environmentally friendly and efficient fluorous phase constructed with dendritic architectures

Traditionally the fluorous phase is generated with perfluorinated alkyl groups that are usually perfluorooctyl or longer and are bioaccummulative and biopersistent and therefore, are considered environmentally unfriendly. Here we report a new concept for the construction of the fluorous phase. This concept is based on the amplification of the fluorous effect with the help of dendritic architectures containing very short semifluorinated groups on their periphery. This new concept was demonstrated by the convergent synthesis of the first and second generation AB₃ and AB₂ benzyl ether dendrons functionalized on their periphery via catalytic nucleophilic addition of their phenolates to perfluoropropyl vinyl ether. The resulting dendrons are liquids. Their fluorous phase affinity was analyzed and demonstrated that the dendritic architecture amplifies the fluorous phase at a specific generation by the number of functional groups on the dendron periphery, and at different generations by increasing their generation number. Therefore, this concept is very efficient for the design and synthesis of new fluorous materials. In addition, by contrast with dendrons containing perfluoroalkyl groups on their periphery, the current dendrons mediate the disassembly of their parent building blocks but do not mediate the self‐assembly in a supramolecular architecture. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2498–2508, 2010