Fluorine-containing alcohols

While methanol and ethanol react readily with a terminal polyfluoroalkene to give a high conversion to the fluorine-containing alcohol, e.g. formation of the extent of the conversion decreases very rapidly when propanol and butanol are employed. 

Optically active fluorine-containing alcohols (91-93% ee) (entries 12 and 13) and deuterio alcohols (84-94% ee) (entries 14 and 15) are synthesized, respectively, by the enantioselective alkylation of fluorine-containing aldehyde and deuterio aldehyde using DBNE. 

Table 8.9 Methacrylates of fluorine-containing alcohols (CH2=C(CH3)COOR) for reflecting layers of polymeric waveguides ...

B.L. Dyatkin, E.R Mochalina, and I.L. Knunyants, The acidic properties of fluorine-containing alcohols, hydroxylamines, and oximes. Tetrahedron 21 (1965), pp. 2991-2995. 

In 2010, closely related conditions were applied to ethyl 2-benzamidomethyl-3-oxo-4,4,4-trifluorobutanoate, leading to the corresponding syn fluorine-containing alcohol as a single stereoisomer, as shown in Scheme 2.18. This product was... 

Fluorocarbon soHds are rare in defoamer compositions, presumably on account of their cost. SoHd fluorine-containing fatty alcohols and amides are known. The most familiar fluorocarbon soHd is polytetrafluoroethylene [9002-84-0]. Because it is more hydrophobic than siHcone-treated siHca, it might be expected to perform impressively as a defoamer component (14). However, in conventional hydrocarbon oil formulations it works poorly because the particles aggregate strongly together. In lower surface tension fluids such as siHcone and fluorocarbon oils, the powdered polytetrafluoroethylene particles are much better dispersed and the formulation performs weU as a defoamer. 

Fluorine-containing compounds can also be synthesized via enantioselective Reformatsky reaction using bromo-difluoroacetate as the nucleophile and chiral amino alcohol as the chiral-inducing agent.86 As shown in Scheme 8-41, 1 equivalent of benzaldehyde is treated with 3 equivalents of 111 in the presence of 2 equivalents of 113, providing a,a-difluoro-/ -hydroxy ester 112 at 61% yield with 84% ee. Poor results are observed for aliphatic aldehyde substrates. For example, product 116 is obtained in only 46% ee. 

The study of these fluorine-containing salts was then extended, and we prepared other new compounds in this series, e.g. 2-fluoroethyl glycine hydrochloride and 2-fluoroethyl betaine hydrochloride (that is, carbofluoroethoxy-methyl trimethyl ammonium chloride). The first of these was readily prepared by the Fischer-Speier esterification of glycine with fluoro-ethyl alcohol ... 

The reaction of perfluoroalkyl iodides with alkenes affords the perfluoro-aikyiated alkyl iodides 931. a.a-Difluoro-functionalized phosphonates are prepared by the addition of the iododifluoromethylphosphonate (932) at room temperature[778], A one-electron transfer-initiated radical mechanism has been proposed for the addition reaction. Addition to alkynes affords 1-perfluoro-alkyl-2-iodoalkenes (933)[779—781 ]. The fluorine-containing oxirane 934 is obtained by the reaction of allyl alcohol[782]. Under a CO atmosphere, the carbocarbonylation of the alkenol 935 and the alkynol 937 takes place with perfluoroalkyl iodides to give the fluorine-containing lactones 936 and 938[783],... 

The products of the electrochemical perfluorination of aliphatic or cyclic ethers are the corresponding perfluorinated ethers. Byproducts are perfluorinated ethers with shorter carbon chains, perfluoroalkanes, perfluorocarboxylic acid fluorides and oxygen difluoride. Cyclic perfluorinated ethers can be produced by electrochemical fluorination of alcohols,32 aliphatic carboxylic acids33 or of their acid halides34 containing not less than four carbon atoms in the chain. 

The 2-chloro-l,2-difluorovinyl ether of furfuryl alcohol also rearranges at — 35l C despite loss of aromaticity. Methanolysis then affords ester 12, which requires heating to 90 C for rearoma-tization. The 2-chloro-l,2-difluorovinyl ether of benzyl alcohol is sufficiently stable to be isolated but rearranges at room temperature methanolysis affords chlorofluoro(2-tolyl)acetic acid ester 13. Apparently, a 1,3-benzyl shift is not favored in this case, as opposed to other fluorine-containing vinyl benzyl ether systems discussed in Section 5.1.3. 

This fluorine-containing, oxidation-resistant alcohol is best oxidized by the Pfitzner-Moffatt reaction, using dichloroacetic acid as catalyst. Observe the use of toluene, instead of carcinogenic benzene, as solvent. A Swern oxidation was not reproducible, and caused substantial epimerization of the isobutyl side chain. Collins oxidation was successful, but ... 

The fluorine-containing hypervalent iodine compound 47, first described by Dess and Martin,5 finds occasional use in the oxidation of alcohols and is described in some substrates as superior than Dess-Martin periodinane.111... 

From fluorine-containing Lewis acids, BF3 is most often used as initiator of the cationic ring-opening polymerization. This is at least partly due to the fact that BF3 forms a stable, well-defined complex with ethers (e.g., BF3 Et20, m.p. = -59°C,b.p. = 125° C) [34]. Complexes of BF3 with ethers or alcohols are the commercial products, whereas gaseous BF3, if needed, may be conveniently obtained by thermal decomposition (>100° C) of relatively less stable complex with anisole. 

In the synthesis of fluorine-containing cellulose ethers we made use of nucleophilic addition of reagents of low nucleophilicity, such as alcohols, to the double bonds of fluorolefins, made possible by the high electronegativity of fluorine. The reaction yields mainly saturated a, a-difluoroethers, but is accompanied by a side reaction with formation of unsaturated ethers, that occurs as a result of the replacement of one of the fluorine atoms ... 

A more convenient approach to the exchange of hydroxy groups by fluorine is one-step activation-substitution - the alcohol is treated with a sufficiently electron-deficient, fluorine-containing reagent which condenses with it, with liberation of a fluoride ion. This ion, in turn, effects nucleophilic replacement of the now present leaving group. Stereochemically, this process results in clean inversion at the carbon center. 

Asymmetric transformation of fluorine-containing ketones or esters into the corresponding optically active alcohols or acids by enzymes along with the discussion on the effect of fluorinated alkyl groups during the enzymatic optical resolution or diastereoselective reactions is described. 

Table IV contains selected examples of the enzymatic resolution of esters with various structures. As was discussed above, enhancement of the optical purity was possible by changing the acyl group or the enzyme (Run 1,2 or 6,7). Noteworthy is the fact that acetate 5 with a trifluoromethyl group was converted by lipase MY into the alcohol with (R) absolute configuration without exception in every case, when the stereochemistry has been determined. However, substrates with the other fluorine-containing substituents furnished alcohols whose asymmetric configuration depended on their structures. Particularly interesting is the relationship between Runs 4 and 5 (18), when resolution was accompanied with simultaneous separation of diastereomers. To the best of our knowledge, this is the first example of the type of resolution of both diastereomers and enantiomers by enzymatic hydrolysis in a single transformation.

---