From other a-halo ethers

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(1) Oxidative desulfurization-fluorination

a-Fluoro ethers from the corresponding a-bromo ethers by substitution.[Furuta, 1998]

 

(2) Optically active Desflurane

The volatile anesthetic (S)-(+)-Desflurane has been prepared in optically active form from R-(-)-Isoflurane by treatment with BrF3[Rozov, 1997]

 

(3) Sevoflurane as a fluoride source

Sevoflurane 1 has been used as a fluoride source in halogen-exchange reactions.[Rozov, 1998]

 

(4) Keck reaction

Application of the Keck reaction to peracetylated glycopyranosylidene dihalides under mild conditions led efficiently to chloro C-allyl glycosides which were converted to either the corresponding C-allyl b-D-glycosides or C-D-glycodienes on treatment with, respectively, tri-n-butyltin hydride and DBU.[Praly, 1997]: see also: [Praly, 2000], [Chen, 2001]

 

(5) Glycosyl fluorides from glycosyl bromides

Nucleophilic substitutions with inversion of the configuration of a-bromine substituents at the anomeric centre with fluorine were effectively realized by refluxing glycosyl bromides with excess triethylamine trishydrofluoride in a two-phase system with carbon tetrachloride.[Miethchen, 1990]

 

 

See also: [Miethchen, 1993], [Miethchen, 1995]

 

(6) Nucleophilic fluorination

Diisopropylethylamine and hydrogen fluoride has been used to make sevoflurane from the corresponding a-chloro ether.[Ramig, 2002]

 

(7) a-Bromo ethers by substitution

a-Bromo ethers can be made from a-chloro ethers by a nucleophilic substitution reaction or an elimination-addition sequence. The nucleophilic substitution reaction can be effected by lithium bromide in tetrahydrofurane or dry hydrogen bromide .[Nakano, 1990, Dersch, 1982] If the a-chloro ether is deactivated for nucleophilic substitution, then it might be necessary to use high temperature for the substitution to occur.

 

 

a-Bromo ethers from a-chloro cthers by an climination-addition sequence

The elimination-addition sequence consists of hydrogen chloride elimination followed by an addition of bromine. This protocol is only applicable to a-chloro ethers prone to hydrogen chloride elimination.[Grummitt, 1956; Grimaldi 1971]