Cesium Fluoride Catalyzed Trifluoromethylation of Esters, Aldehydes, and Ketones with (Trifluoromethyl)trimethylsilane.

The low reactivity of carboxylic esters toward (trifluoromethyl)trimethylsilane (TMS-CF(3)) was investigated. A universal cesium fluoride catalyzed procedure for nucleophilic trifluoromethylation was developed. At room temperature (25 degrees C), with catalytic amounts of cesium fluoride, carboxylic esters were found to react to give the silyl ether intermediates, which afforded the trifluoromethyl ketones after hydrolysis.

New Electrophilic Trifluoromethylating Agents.

Synthetic routes to S-(trifluoromethyl)phenyl-4-fluorophenylsulfonium triflate (8), S-(trifluoromethyl)phenyl-2,4-difluorophenylsulfonium triflate (9), S-(trifluoromethyl)phenyl-3-nitrophenylsulfonium triflate (10), and S-(trifluoromethyl)-4-fluorophenyl-3-nitrophenylsulfonium triflate (11) are described. They are stable molecules and conveniently prepared by treating phenyl trifluoromethyl sulfoxide with benzene and its derivatives. These novel electrophilic trifluoromethylating agents react under mild conditions with a variety of aromatic rings (p-hydroquinone, pyrrole, and aniline) to give trifluoromethylated compounds (2-trifluoromethyl-p-hydroquinone, 2-trifluoromethylpyrrole, 2-trifluoromethylaniline, and 4-trifluoromethylaniline) in moderate to high yields.

Reactions of Iodoperfluoro-3-oxaundecylsulfonyl Fluoride with Halohydrocarbons through Organometallic Intermediates.

Iodoperfluoro-3-oxaundecylsulfonyl fluoride reacted with Cu, Zn, or Grignard reagent to produce the respective organometallic species, which was further reacted with halohydrocarbons 4-ClC(6)H(4)Br, 4-CH(3)C(O)C(6)H(4)Br, CH(2)=CHCH(2)Br, and CH(3)SiCl, to give derivatives of R(CF(2))(8)O(CF(2))(2)SO(2)F [R = 4-ClC(6)H(4) (7), 4-CH(3)C(O)C(6)H(4) (5), CH(2)=CHCH(2) (3), and CH(3)Si (13)], in moderate yields. The compounds were characterized by NMR, infrared, and mass spectroscopy as well as elemental analyses. The addition product of trichlorosilane and 3 was reacted with sodium methoxide to give (12H,12H,13H,13H,14H,14H-hexahydroperfluoro-3-oxatetradecyl methylsulfonate) trimethoxysilane, [(CH(3)O)(3)Si(CH(2))(3)(CF(2))(8)O(CF(2))(2)SO(3)Me] (11).

Selective Reactivity of the Phosphorus-Chlorine and Carbon-Chlorine Bonds in Cyclic Chlorocarbaphosphazenes: An Unusual Activation of a Carbon-Nitrogen Bond in Trialkylamines.

Acyclic tertiary amines such as triethylamine and tri-n-propylamine used as HCl scavengers in nucleophilic substitution reactions of cyclic chlorocarbaphosphazenes [N(3)PC(2)Cl(4) (I) and N(3)P(2)CCl(5) (II)] with (CF(2))(n)()(CF(2)CH(2)OH)(2) [n = 0 (III) or 1 (IV)] are found to undergo a facile C-N bond cleavage with the regiospecific substitution of the dialkylamino groups on the ring carbon atoms of the carbaphosphazene. In the case of cyclic amines such as 1-methylpiperidine and 4-methylmorpholine, the cleavage was found to occur regiospecifically at the N-CH(3) bond, resulting in the ring substitution of the cyclic secondary amino group on the dicarbaphosphazene ring carbon atoms. The polyfluoro diol III forms a spirocyclic ring exclusively at the phosphorus site in compounds [CF(2)CH(2)O](2)PN(3)C(2)[N(C(2)H(5))(2)](2) (1), [CF(2)CH(2)O](2)PN(3)C(2)[N(C(3)H(7))(2)](2) (2), [CF(2)CH(2)O](2)PN(3)C(2)[NCH(2)(CH(2))(3)CH(2)](2) (3), and [CF(2)CH(2)O](2)PN(3)C(2)[N(CH(2))(2)O(CH(2))(2)](2) (5) along with the formation of carbon-substituted carbaphosphazenes, Cl(2)PN(3)C(2)[NCH(2)(CH(2))(3)CH(2)](2) (4) and Cl(2)PN(3)C(2)[N(CH(2))(2)O(CH(2))(2)](2) (6).

Insertion of Fluoroalkenes into Activated C-H Bonds for the Preparation of Polyfluorinated Sulfanes, Alcohols, and Acyclic and Cyclic Ethers.

Free radical addition reactions of tetrahydrothiophene, pentamethylene sulfide, and 1,4-thioxane with various cyclic and acyclic per- and polyfluorinated olefins are readily initiated by di-tert-butyl peroxide, providing a convenient route for synthesizing cyclic sulfanes with fluorinated side groups. Tetrahydrothiophene reacts with hexafluoropropene, perfluoroallylbenzene, perfluorocyclobutene, and 1,2-dichlorotetrafluorocyclobutene in the presence of catalytic amounts of the peroxide to give the corresponding addition products CH(2)CH(2)CH(2)SCHCF(2)CHFCF(3) (1), CH(2)CH(2)CH(2)SCHCF(2)CHFCF(2)C(6)F(5) (2), CH(2)CH(2)CH(2)SCHCFCHFCF(2)CF(2) (3), and CH(2)CH(2)CH(2)SCHCClCHClCF(2)CF(2) (4), respectively. Pentamethylene sulfide reacts analogously with hexafluoropropene to give CH(2)CH(2)CH(2)CH(2)SCHCF(2)CHFCF(3) (8).

Synthesis of Cyclic Ethers with Fluorinated Side Chains.

Di-tert-butyl peroxide initiated free radical addition of THF to various fluorinated alkenes (CF(2)=CH(2), CF(2)=CFH, CH(2)=CHCF(3), CF(2)=CFCF(3), CF(2)=CFC(5)F(11), CF(2)=CFOCF(2)CF(CF(3))OCF(2)CF(2)SO(2)F) gives either bidirectional addition products [CH(2)CH(2)CH(2)OCH(CF(2)CH(3)) (1), CH(2)CH(2)CH(2)OCH(CH(2)CHF(2)) (2), CH(2)CH(2)CH(2)OCH(CF(2)CH(2)F) (3), and CH(2)CH(2)CH(2)OCH(CFHCHF(2)) (4)] or unidirectional products [CH(2)CH(2)CH(2)OCH(CH(2)CH(2)CF(3)) (5), CH(2)CH(2)CH(2)OCH(CF(2)CHFCF(3)) (6), CH(2)CH(2)CH(2)OCH(CF(2)CHFC(5)F(11)) (7), and CH(2)CH(2)CH(2)OCH(CF(2)CHFOCF(2)CF(CF(3))OCF(2)CF(2)SO(2)F) (8)] depending on the structure of the alkene. Reaction of dioxane with CF(2)=CFOCF(2)CF(CF(3))OCF(2)CF(2)SO(2)F gives a single product, CH(2)OCH(2)CH(2)OCH(CF(2)CHFOCF(2)CF(CF(3))OCF(2)CF(2)SO(2)F) (9). In the case of hexafluoropropene or perfluoroallylbenzene, reaction with an excess of tetrahydrofuran gives only the monosubstituted products CH(2)CH(2)CH(2)OCH(CF(2)CHFCF(3)) (6) and CH(2)CH(2)CH(2)OCH(CF(2)CFHCF(2)C(6)F(5)) (11) respectively.