Alkoxides perfluoro

Rase-catalyzed reaction of alcohol favors addition, whereas increasing amounts of alkoxide favor addition-elimination reactions. Perfluoro-2-methyl-2-pentene and methanol form the saturated ether, whereas two equivalents of sodium methoxide form the vinylic ether [S] (equation 4). 

When the pentamer (66) reacts with alkoxide anions at low temperatures (-30 to -40°C), then the products of kinetic control (102) are isolated, whereas at higher temperatures, thermodynamic control prevails and the products (103) are obtained [131,132] (Scheme 68). Similar observations have been made with sulphur nucleophiles [132], and complex products are obtained with amines, including the formation of heterocycles [132]. Reaction of (66) with ethyl acetoacetate gave a pyran derivative (104) in a reaction that may be rationalised as shown in Scheme 69 [133]. In an analogous way.furan derivatives are formed from perfluoro-2-butene and -cyclohexene in base-induced reaction with 1,3-dicarbonyl derivatives [133]. 

The generation of highly fluorinated tertiary alkoxides and alcohols by the use of triniethyl-(trifluoromcthyl)silane and its analogs is most important.A simple, high-yield synthesis of perfluoro(l,l-diniethylethanol) from either hexafluoroacetone or difluorophosgene with trimcthyl(trinuoroniethyl)silaiie probably represents the best overall route to this alcohol to date.""- - " ... 

Perfluoro-3,3 - bipyridyl Alkoxide ions, NH3, N2H4 MeLi 282... 

Oxygen.—Alcohols, Alkoxides, Esters, and Ethers. Information culled from the patent literature is presented at the end of this chapter (p. 303). The ether chemistry associated with perfluoro-olefins, etc., is noted in Chapter 2 except that which is connected with polymers derived from vinyl ethers (see p. 280). Fluoronitro-alcohols, -esters, and -ethers are dealt with in the nitrogen section of this Chapter (p. 246). 

A useful building block 519 for vitamin D synthesis was prepared by reaction of the alkenyloxirane 517 [195], Under usual conditions of the elimination, both the dienyl alcohol 519 and the unsaturated ketone 520 were formed in equal amounts. Radinov and co-workers discovered an interesting and remarkable effect of the addition of fluorinated alcohols, such as l,3-bis-(l,l,l,3,3,3-hexafluoro-2-hydroxypropyl)benzene or perfluoro-t-butyl alcohol as a proton source, on the chemoselectivity, and the desired 519 was obtained with nearly complete chemos-electivity with these additives [195], They suggest that rapid protonation of the intermediate alkoxide 518 with these alcohols seems to be important. 

The alkali-metal derivatives of perfluoro-t-butyl alcohol, (CF3)sC OM (M = Li, Na, or K), best prepared by reaction of the alcohol with metal hydride in anhydrous ether, have been shown to resist thermal decomposition [for example, the sodium alkoxide can be melted (143 °Q and distilled (232°C) with no apparent change in composition] the same is true of the alkoxides CF3aC(CF3)3-ONa, Ca,-C(CF8)2-ONa, and (CF3)2CHOM (M = Li or Na), which likewise possess no a-fluorine substituent [cf. 

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