Loomis S. Chen

The synthesis and reactins of ortho bromophenyllithium

Abstract Experimental conditions have now been developed whereby o -bromophenyllithium(II) may be prepared in excellent yields and used as an organometallic intermediate for the synthesis of a variety of ortho bromo substituted phenyl compounds ( o -BrC 6 H 4 X). THe thermal stability, decomposition products and reactions of II wre studied. REactions between II and a variety of substrates, e.g., CO 2 , dimethylformamide, fluorinated esters, hexafluorobenzene, and organosilicon chlorides were examined.

Perfluoroalkylations and perfluorooxaalkylations. Part 2. Copper-mediated cross-coupling of secondary perfluorooxaalkyl iodides and aryl halides [1]

Abstract The first successful application of the copper-mediated cross-coupling reaction using secondary perfluorooxaalkyl iodides and iodoaromatic substrates is described. The yields of the cross-coupled products are optimized by careful choice and control of the experimental conditions. The by-products formed are identified and their probable mode of formation is discussed.

NEW METHODS FOR THE PREPARATION OF PERFLUOROALKYL- AND PERFLUOROALKYLETHER-S-TRIAZINES

Abstract Two new single-step processes are provided for the preparation of 2,4,6-tris(perfluoroalkyl) and (perfluoroalkylether)-1,3,5-triazines. One method involves the nucleophilic substitution of cyanuric fluoride with (perfluoroalkyl) and (perfluoroalkylether)trimethylsilanes in the presence of cesium fluoride. Substituted s-triazines, 2,4,6-(R f ) 3 C 3 N 3 ( IIa-d ) { IIa , R f = n -C 8 F 17 ; IIb , R f = (CF 3 ) 2 CFO(CF 2 ) 4 ; IIc , R f =C 3 F 7 OCF(CF 3 )CF 2 OCF(CF 3 ); IId , R f =C 3 F 7 O[CF(CF 3 )CF 2 primary or secondary carbon atoms next to the ring can be produced by this method in reasonable yields, 41–77%. Using the second method, substituted triazin prepared by the cross-coupling reactions of cyanuric chloride with perfluoroalkyl and perfluoroalkylether iodides in the presence of copper powder. This method can only produce substituted triazines with primary carbon atoms adjacent to the ring.

Reaction of phosphorus pentachloride with perhalo carbonyl-containing compounds☆

Abstract The reaction between PCI5 and the carbonyl oxygen in a variety of perfluoro compounds containing the carbonyl functional group, e.g. RfC(O)R′f, RfC(O)X or XC(O)RfC(O)X, where X = Cl, F, OH, NH2, and ONH4 has led to a convenient synthesis procedure for fluorochloro compounds. Monoketones, e.g. RfC(O)R′f, yield RfCCl2R′f compounds, while the diketones, e.g. RfC(O) (CF2)nC(O)R′f, also react to yield the fluorochloro compounds. When n = 3, RfCCl2(CF2)3CCl2R′f is produced in quite high yields (65 percent); however, when n = 2, the principal products is a cyclic fluorodichloroether compound while the fluorotetrachloro compound is the minor product. The RfC(O)X and XC (O)RfC(O)X compounds produce RfCCl3 and Cl3CRfCCl3 respectively in high yields. Reaction temperature and pressure are important factors for high yield synthesis.

Synthesis and reactions of a perfluoroalkylether Grignard reagent containing a functional ester group

Abstract The first perfluoroalkylether magnesium bromide containing a functional ester group, ROC(O) (CF2)4OCF2CF2MgBr(I) has been synthesized through the metal-halogen exchange reaction between a perfluoroalkylether iodide ester and ethylmagnesium bromide. The thermal stability in diethyl ether of the Grignard reagent and the products of the Grignards intermolecular reaction at higher temperatures have been established. Reactions of the Grignard reagent with various substrates such as water, diethyl oxalate, ethyl formate, diethyl carbonate, ethyl acetate, ethyl benzoate and ethyl trifluoroacetate indicate the synthetic utility of this Grignard reagent.

Perfluoroalkylations and perfluorooxaalkylations. Part 3. Chloro-substituted diazines as substrates in copper-mediated cross-coupling

Abstract The (perfluoroalkyl)- and (perfluorooxaalkyl)diazines, 2,4-bis(perfluorooctyl)pyrimidine ( 3 ), 2,4,6-tris(perfluorooctyl)pyrimidine ( 6a ), 2,4,6-tris(perfluoro-6-methyl-5-oxaheptyl)pyrimidine ( 6b ), 3,6-bis(perfluorooctyl)pyridiazine ( 10 ) and 2,6-bis(perfluorooctyl)- pyrazine ( 13 ), have been prepared in good yield. This was accomplished by using chloro-substituted diazines as substrates in copper-mediated cross-coupling reactions with perfluoroalkyl and perfluorooxaalkyl iodides. The yields of the cross-coupled products are influenced by the reaction conditions as well as by the structure of the fluoroaliphatic iodides and substrates.

Perfluoroalkylations and perfluorooxaalkylations. Part 1. Bromoaromatics as substrates in copper-mediated cross-coupling

Abstract Tribromobenzenes, bromobiphenyl ethers and a bromoterphenyl ether have been used as substrates in copper-mediated cross-coupling reactions with perfluoroalkyl and perfluorooxaalkyl iodides. Excellent yields were obtained from perfluoroalkyl iodides as well as the ether iodides in which the ether oxygen was situated at position 5 or higher. However, ether iodides where the ether oxygen was at the 3-position gave only traces of the cross-coupled product, if any. This difference in reactivity is based on the relative position of the ether linkage to the reaction site and was more pronounced in reactions with aryl bromides than in reactions with aryl iodides.

Free-radical initiated addition of carbon tetrachloride to fluoro olefins

Abstract The reaction between carbon tetrachloride and unsymmetrical fluoro olefins, e.g. RCFCF2, where R=n−C5F11 and C6F5, has led to the addition product, RCFClCF2CCl3. Addition was apparently unidirectional under the conditions used since the isomeric adduct RCF(CCl3)CF2Cl could not be detected. The effects of experimental conditions such as free radical initiators, temperature, and time are discussed for the different reactions studied. A probable mechanism is suggested for these additions.

Perfluoro tertiary alcohols. III. (Perfluoroalkyl)- and (perfluorooxaalkyl)-trimethylsilanes in the synthesis of perfluorinated tertiary alcohols☆

Abstract High-molecular weight perfluorinated tertiary alcohols, R f 1 R f 2 R f 3 C(OH) R f 1 = n-C 8 F 17 , R f 2 =CF 3 , R f 3 =n-C 6 F 13 ; R f 1 = (CF 3 ) 2 CFO(CF 2 ) 4 , R f 2 = CF 3 , R f 3 = n-C 6 F 13 ,·R f 1 = C 3 F 7 O[CF(CF 3 )CF 2 O] 2 CF(CF 3 ), R f 2 = CF 3 , R f 3 = n-C 6 F 13 ; R f 1 = n-C 8 F 17 , R f 2 = CF 3 O[CF 2 CF(CF 3 )O] 2 (CF 2 ) 2 , R f 3 = (CF 3 ) 2 CFO(CF 2 ) 2 ( IIIa–d ), have been prepared by the reactions of (perfluoroalkyl)- and (perfluorooxaalkyl)-trimethylsilanes ( Ia–d ) with fluoroketones ( IIa–c ). Ketones containing a trifluoromethyl group as well as higher molecular weight perfluorinated substituents have been studied under different experimental conditions. The yield of tertiary alcohol is influenced by the solvents, reaction temperatures, type and concentration of metal fluorides, and structures of the fluoroalkyltrimethylsilanes and fluoroketones. The reaction has been extended to carbonyl compounds other than ketones. While a perfluorinated secondary acid fluoride gave good yield of the ketone, no reaction was observed with esters.

Thermal decomposition of low-molecular weight perfluoroalkylethers

Abstract Seven low-molecular weight perfluoroalkylethers have been subjected to thermal degradation using a flow pyrolyzer attached to a gas Chromatograph, and the results are compared with thermal decomposition of two perfluoroalkanes. Both linear and branched ethers were studied. The major degradation products from the ethers were identified by GC/MS. Products due to specific C-O bond fission were detected from only two of the ethers. Hexafluoropropylene was the most prominent product from all the ethers studied. While the perfluoroalkylethers in general were more stable than perfluoroalkanes, linear ethers were more stable than branched ethers. The stability of the ethers also decreased with increasing number of adjacent C-C bonds.