Reaction fluorous solvent

Catalyst Fluorous solvent Reaction occurs Catalyst Fluorous solvent... 

Better retention into the fluorous phase was observed when using a polar fluorous solvent and hexane (>99.82%, insoluble catalyst emulsified in homogeneous reaction mixture) than when using a PFMC and acetone (97.5%), as expected for the ionic... 

Bayardon and Sinou have reported the synthesis of chiral bisoxazolines, which also proved to be active ligands in the asymmetric allylic alkylation of l,3-diphenylprop-2-enyl acetate, as well as cyclopropanation, allylic oxidations and Diels-Alder reactions. [62] The ligands do not have a fluorine content greater than 60 wt% and so are not entirely preferentially soluble in fluorous solvents, which may lead to a significant ligand loss in the reaction system and in fact, all recycling attempts were unsuccessful. However, the catalytic results achieved were comparable with those obtained with their non-fluorous analogues. 

In their original incarnations,1201 fluorous techniques were designed with the notion that fluorous solvents should be used in both the reaction stage... 

Reducing the number of fluorines on the fluorous tag also provides a general solution to the reaction solvent problem as the number of fluorines is reduced, the solubility in organic solvents tends to go up. Of course, the solubility in fluorous solvents tends to go down at the same time, and the residual tag must strike a balance between too many fluorines (low solubility in organic solvents) and too few fluorines (cannot easily be separated from organic compounds). However, thanks to the technique of fluorous solid-liquid extraction, there is surprisingly broad latitude here. 

The term fluorous was coined as an analogy to aqueous for highly fluorinated alkanes, ethers and tertiary amines [1], These compounds differ markedly from the corresponding hydrocarbon compounds to the extent that such compounds commonly give bilayers with conventional organic solvents. In this chapter, we will discuss the different approaches towards carrying out reactions in fluorous media and describe how reactants and catalysts can be engineered to be preferentially soluble in fluorous solvents. 

Fluorous compounds with appropriate melting and boiling points can be used as solvents for reactions. Fluorous compounds that have been used as solvents for a variety of reactions include perfluoromethylcyclohexane (PP2) and perfluoro-hexane (Figure 3.1). 

Figure 3.4 Some examples of perfluoroalkyl-substituted molecules suitable for reactions in fluorous solvents...

The fluorous solvent alone had a minimal effect on the outcome of the reaction. However, with the fluorinated ligand, the rr.iso ratio was found to increase with increasing phosphine concentration, reaching a value of almost 8 1 at a phosphine to rhodium ratio of 103 1. The beauty of this system was demonstrated by its use in a semicontinuous hydroformylation experiment. After each... 

Aldehydes may be converted to carboxylic acids using Ni(acac)2 immobilized in [bmim][PF,5], with oxygen as the oxidant, as shown in Scheme 9.14 [27], A similar reaction has also been performed using perfluorinated solvents, and it was found that there was little difference between the two systems [28], However, the Ni(acac)2 catalyst could not be used directly in the fluorous solvent and therefore the 1,3-diketonate was modified with long perfluorinated chains prior to use to ensure solubility. 

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