亚磺化脱卤研究-连二亚硫酸钠引发的全氟烷基自由基对双键的加成

全氟碘代烷或溴代烷与亚硫酸盐或连二亚硫酸钠所发生的亚磺化脱卤反应表现自由基反应的特征,提供了用化学方法截捕全氟烷基自由基中间体的可能性:R_FX SO_2(?)[R_FX·SO_2](?)R_F· X~- SO_2.实验表明,在烯烃存在下,全氟碘代烷或溴代烷可以在亚磺化脱卤的同时生成较高产率的自由基加成产物.连二亚硫酸钠可作为全氟烷基自由基引发剂尚未见文献报道.本文报道了这一工作.全氟碘代烷在连二亚硫酸钠-碳酸氢钠的乙腈水溶液中,与1～1.5当量的烯烃在室温或稍高的温度下反应.即可获得相应的自由基加成产物.产率为50～80％:     

连二亚硫酸钠的亚磺化脱卤反应研究

本论文分两个部分,第一部分"全氟及多氟烷基卤化物的亚磺化脱卤反应"对连二亚硫酸钠与全氟烷基碘化物的作用进行考察,在碘化物S-碘-3-氧杂-八氟磺酸钠进行亚磺化脱碘反应并得到验证后,将反应用于其他带极性基因的全氟烷基碘化物上,随即采用相转移催化及共溶剂技术将反应推广到一般的全氟碘代烷上,证明连二亚硫酸钠对广谱的全氟烷基碘化物都是一个有效的便利的亚磺化脱碘试剂。在亚磺化脱碘研究的同时,还进行了亚磺化脱澳研究,得到了相应的全氟烷基亚磺酸及1,1-二卤亚磺酸盐。将全氟碘代烷与电化学体系中连续产生的二氧化硫阴离子基反应,得到了预期的全氟烷基亚磺酸盐,从而证实了二氧化硫阴离子墓确实是作为亚磺化反应主体的亲核试剂,电化学亚磺化脱碘反应将异相反应转化为均相反应,是一种很有前途的合成方法。仲全氟卤代烷与连二亚硫酸钠反应只能得到脱卤氢化产物,这和伯全氟碘代烷亚硫化的副产物一起,都说明了在这还原性体系中全氟烷自由墓形成全纸烷基阴离子的可能性。     

脱卤亚磺化研究——-四氯化碳及1,1,1-三氯多氟烷烃的脱氯亚磺化反应

全氟碘代烷及溴代烷与连二亚硫酸钠反应可生成对应的亚磺酸钠,但全氟氯代烷(R_FCl)在相同条件下不能发生类似的反应.本文报道某些RCCl_3型化合物在相当温和的条件下发生脱氯亚磺化反应,得到α,α-二氯多氟烷基亚磺酸盐(RCCl_2SO_2Na)的研究结果. 在水和乙腈的共溶剂反应体系中,四氯化碳(1a)和氟氯烷1b～1f均可在25℃下与连二亚硫酸钠-碳酸氢钠反应,生成相应的亚磺酸钠盐2a～2f,产率可达80％以上.这些亚磺酸盐与氯气反应均可转化为对应的磺酰氯3a～3f,产率75～90％.     

亚磺化脱卤研究 VIII, 连二亚硫酸钠引发的全氟烷自由基对双键的加成

碘代全氟烷与连二亚硫酸钠进行的亚磺化脱碘反应具有自由基反应的特征,从而提供了用化学方法截捕全氟烷自由基中间体的可能性,我们用烯烃作为自由基截捕剂,得到了碘代全氟烷与烯烃的自由基链式反应产物,由不同烯烃可得到1:1的加成物或调聚物,本文对加成反应与亚磺化脱碘反应的关系及阻聚剂对反应的影响进行了探讨。     

亚磺化脱卤研究III.全氟伯碘代烷及a,w-全氟伯碘代烷在连二亚硫酸钠作用下的亚磺化脱碘反应

应用相转移催化和加入共溶剂的技术,全氟碘代烷如Cl(CF2)2I(1a)、Cl(CF2)4I(1b),Cl(CF2)6I(1c),H(CF2)8I(1d),C4F9I(1e),C6F13I(1f),C8F17I(1g)及α,ω-全氟二碘代烷如(ICF2CF2)2O(3a),I(CF2)6I(3b),I(CF2)8I(3c),I(CF2)10I(3d)等均可与连二亚硫酸钠水溶液在温和的条件下发生亚磺化脱碘反应,生成全氟亚磺酸盐Cl(CF2)2SO2Na(2a),Cl(CF2)4SO2Na(2b),Cl(CF2)6SO2Na(2c),H(CF2)8SO2Na(2d),C4F9SO2Na(2e),C6F13SO2Na(2f),C8F17SO2Na(2g)及O(CF2CF2SO2K)255a),KO2S(CF2)6SO2K(5b),KO2S(CF2)8SO2K(5c),KO2S(CF2)10SO2K(5d)全氟α,ω-二亚磺酸钠易潮解,均转化为相应的钾盐。这些亚磺酸盐均可用常规方法氯化成对应的磺酰氯,从而提供了由全氟碘代烷、二碘代烷制备全氟亚磺酸盐、二亚磺酸盐及全氟磺酸,二磺酸及衍生物的一种实用方法。     

亚磺化脱卤研究 Ⅷ.连二亚硫酸钠引发的全氟烷自由基对双键的加成

碘代全氟烷与连二亚硫酸钠进行的亚磺化脱碘反应具有自由基反应的特征,从而提供了用化学方法截捕全氟烷自由基中间体的可能性.我们用烯烃作为自由基截捕剂,得到了碘代全氟烷与烯烃的自由基链式反应产物.由不同烯烃可得到1∶1的加成物或调聚物.本文对加成反应与亚磺化脱碘反应的关系及阻聚剂对反应的影响进行了探讨.     

亚磺化脱卤研究IV全氟伯溴代烷及α,ω-二溴代烷的亚磺化脱溴反应

应用相转移催化或加入共溶剂的技术,全氟伯溴代烷及α,ω-二溴代烷均可在水溶液中与Na2S2O4-NaHCO2反应,生成相应的全氟亚磺酸盐及二亚磺酸盐,产率66-97%。     

亚磺化脱卤研究 VII. 全氟碘代烷与SO~3^-的反应

全氟碘代烷R~FI[R~F=CF~3(CF~2)~5(1a);H(CF~2)~4(1b);H(CF~2)~8(1c);Cl(CF~2)~6(1d);Cl(CF~2)~8(1e)Cl(CF~2)~8(1f);;NaO~3S(CF~2)~20(CF~2)~2(1g);NaO~3S(CF~2)~2O(CF~2)~4(1h)]及α,ω-二碘化物I(CF~2)~nI[n=4(1i);n=6(1j)]与Ce^4^+-亚硫酸氢钠于70℃左右、pH3～4的溶液中反应,形成相应的全氟烷基亚磺酸盐,产率70～85%。全氟氯代烷和全氟溴代烷在同样条件下未能发生反应。     

亚磺化脱卤研究 Ⅳ.全氟伯溴代烷及α,ω-二溴代烷的亚磺化脱溴反应

应用相转移催化或加入共溶剂的技术,全氟伯溴代烷及α,ω-二溴代烷均可在水溶液中与Na_2S_2O_4-NaHCO_3反应,生成相应的全氟亚磺酸盐及二亚磺酸盐,产率66～97％。     

亚磺化脱卤研究 X: 全氟及多氟溴代烷的反应研究

本文报道溴代全氟烷和α,ω-二溴代全氟烷在亚磺化脱卤反应体系中与烯烃的反应及其与相应的碘代全氟烷的区别. 合成了全氟仲溴代烷CF3CFBrOCF2CF(CF3)O(CF2)2SO2F(7), 它与烯烃反应可得到1:1的加成物. 7的水解产物CF3CFBrOCF2CF(CF3)O(CF2)2SO3Na(11)与连二亚硫酸钠反应只得到氢化脱溴产物. 多氟溴化物CF3CBr2X(13X=F; 14X=Cl; 15X=Br)经亚磺化脱溴可得到相应的亚磺酸钠盐CF3CBrXSO2Na(16X=F; 17X=Cl; 18X=Br), 其中间体多氟烷自由基可用烯烃捕集, 得到高产率的1:1加成产物.     

Studies on sulfinatodehalogenation: III. The sulfinatodeiodination of primary perfluoroalkyl iodides and α,ω-perfluoroalkylene diiodides by sodium dithionite

Using P. T. C. or cosolvents, both perfluoroalkyl iodides such as Cl(CF₂),_nI (n=2, 4, 6, 1a-1c), H(CF₂)₈I (1d), CF₃(CF₂)_nI (n=3, 5, 7, 1e-1g), and α. ω-perfluoroalkylene diiodides such as (ICF₂CF₂)₂O (4a), I (CF₂)_nI (n=6, 8, 10, 4b-4d) reacted smoothly with sodium dithionite in aqueous solution under mild conditions to give the corresponding perfluoroalkanesulfinates Cl(CF₂)_nSO₂Na (n=2, 4, 6, 2a-2c), H(CF₂)₈SO₂Na (2d), CF₃(CF₂)nSO₂Na (n=3, 5, 7, 2e-2g), α, ω-perfluoroalky-lenedisulfinates O (CF₂CF₂SO₂K)₂ (5a), and KO₂S(CF₂)_nSO₃K (n=6, 8, 10, 6b-6d) in moderate to high yields. These sulfinates were converted to the corresponding sulfonyl chlorides by reacting with chlorine in the usual way. Thus the discovery of the new reagent renders sulfinatodeiodination a practical method for the synthesis of perfluorosulfinic and perfluorosulfonic acids and their derivatives from the corresponding perfluoroalkyl iodides.     

One-step synthesis of epoxy(perfluoroalkyl)alkenes

Epoxy(perfluoroalkyl)alkenes were synthesized in one step by reaction of perfluoroalkyl iodides with 2-(allyloxymethyl)oxirane and 2-(oct-7-en-1-yl)oxirane in the presence of sodium dithionite and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) under mild conditions.     

Studies on sulfinato-dehalogenation: XII. Sodium dithionite-initiated addition of N,N-diethyliododifluoroacetamide to multiple bonds

N, N-deithyl-iododifluoroacetamide 1 reacted with alkenes, alkynes in aqueous acetonitrile solutions of sodium dithionite and sodium hydrogen carbonate at room temperature to give the corresponding adducts, thus constituting a new method for introducing the CF₂ group into organic molecules. Compound 1 reacted with conjugated olefins 2b, c to afford the iodine-free adducts 7b, c. The adducts 3d—f, from addition of 1 to alkenes 2d—f, could be converted into α,α-difluoro-γ-lactones 5d—f by treatment with silica gel. Compound 1 reacted with ethyl vinyl ether 2i to give aldehyde 8, and perfluoroalkyl or polyfluoroalkyl iodides reacted similarly. A radical mechanism was proposed for the addition reaction. Under the same condition, N,N-diethyl-bromodifluoroacetamide produced only the corresponding sulfinate Et₂NC(O)CF₂SO₂Na.     

The sulfinatodehalogenation of primary polyfluoroalkyl iodides by sodium sulfite

Polyfluoroalkyl iodides, such as Cl(CF2)nI(n=4, 6, 8, 1b-1d) and F(CF2)nI (n=6, 8,1e-1f) reacted with sodium sulfite in neutral aqueous DMF solution to give the corresponding sulfinates Cl(CF2)nSO2Na (n=4, 6, 8, 2b-2d) and F(CF2)nSO2Na (n=6, 8, 2e-2f) in moderate yields. I(CF2)2O(CF2)2SO2F ( la ) reacted under the same condition to give 3-oxa-octafluoropentane-1,5-disulfinates (2a).     

Practical and efficient synthesis of perfluoroalkyl iodides from perfluoroalkyl chlorides via modified sulfinatodehalogenation

A novel two-step one pot synthesis of perfluoroalkyl iodides (α,ω-diiodoperfluoroalkanes) from perfluoroalkyl chlorides (α-chloro-ω-iodoperfluoroalkanes) has been developed by initial conversion to the corresponding sodium perfluoroalkanesulfinates with sodium dithionite and then subsequent oxidation by iodine.     

Reactions of [2-iodo-3-(perfluoroalkyl)propyl]glycidyl ethers with alcohols under basic conditions

On treatment with sodium alkoxides in the corresponding alcohols, [2-iodo-3-(perfluoroalkyl)propyl]glycidyl ethers are converted into 3-alkoxy-1-[3-(perfluoroalkyl)prop-2-enyloxy]-propan-2-ols in 56–78% yields, while its reaction with 2,2,2-trifluoroethanol and phenol under phase transfer conditions (NaOH, CH₂Cl₂-H₂O, Bu₄N⁺I⁻, 35–40 °C) gives 3-alkoxy1-[2-iodo-3-(perfluoroalkyl)propoxy]propan-2-ols (yields 45–72%).     

Fluoroalkylation of porphyrins: synthesis and reactions of beta-fluoroalkyltetraarylporphyrins

Treatment of 5,10,15,20-tetraarylporphyrins (1) with perfluoroalkyl iodides (2) in the presence of Na(2)S(2)O(4)/NaHCO(3) in DMSO-CH(2)Cl(2) at 30-40 degrees C for several hours gives the corresponding 2-perfluoroalkylporphyrins (3). Nucleophilic attack on 3 with dimethyl malonate, diethyl malonate, malonitrile, or cyano acetate (Nu) anion results in the formation of (E)-3-Nu-2-perfuoroalkyl(methylenyl)chlorins. Electrophilic substitution on 3 with NBS or NO(2) affords regioselectively the corresponding 12(or 13)-bromo- and 12,13-dibromo- or nitroporphyrins.     

Studies on sulfinatodehalogenation XXIII. A new sulfinatodehalogenation reagent: thihurea dioxide1

HSO₂^? generated from thiourea dioxide and sodium bicarbonate in aqueous CH₃CN at 35–45°C reacted with perfluoroalkyl iodides, polyfluoroalkyl bromide, 1,1,1-trichloro-2,2,2-tri-fluoroethane and carbon tetrachloride to give the corresponding sulfinates in good yield. Furthermore, it was shown that the reagent was able to initiate the addition of perfluoroalkyl iodide to olefins and alkynes at 30°C.     

Versatile synthesis of 3,5-disubstituted 2-fluoropyridines and 2-pyridones

5-bromo-2-fluoro-3-pyridylboronic acid (3) was prepared in high yield by ortho-lithiation of 5-bromo-2-fluoropyridine (1), followed by reaction with trimethylborate. Suzuki reaction of 3 with a range of aryl iodides gave 3-monosubstituted 5-bromo-2-fluoropyridines 4 in excellent yields. A second Suzuki reaction utilizing the bromo constituent of 4 with aryl and heteroaryl boronic acids provided 3,5-disubstituted 2-fluoropyridines 5, which in turn could be converted to the corresponding 2-pyridones 6.