HOMOGENEOUS NUCLEOPHILE EXCHANGE .2. SILVER-FREE DIRECT SYNTHESIS OF PRIMARY ALKYL SULFONATES FROM ALKYL-HALIDES
HOMOGENEOUS NUCLEOPHILE EXCHANGE .2. SILVER-FREE DIRECT SYNTHESIS OF PRIMARY ALKYL SULFONATES FROM ALKYL-HALIDES
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DOI：
10.1021/jo00259a035
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发表时间：
1988-11-25
影响因子：
3.6
通讯作者：
TOMPKINS, J
中科院分区：
文献类型：
--
作者：
HAHN, RC;TOMPKINS, J
最近，在发现均相的季铵盐催化的烷基卤化物交换1从未被系统探索的基础上，我们利用这一过程发展了一种快速、简单、无溶剂的方法来进行溴-氯、氯-碘和溴-碘的交换，并将其应用于某些-杂二卤化物的高产率合成。2实现可逆的氯-碘交换的能力鼓励我们尝试将卤代烷前所未有的均相转化为烷基磺酸盐；在此报告了一些初步的成功。尽管在历史上，磺酸盐离子的主要作用是在SN1或SN2类型的过程中离开基团，但泽菲罗夫最近指出，像Swain-Scott标度这样的亲核性标度“完全忽略了……的亲核性质”。如对甲苯磺酸离子这样的典型的核疏水作用“。事实上，Kevin 4已经证明了芳基磺酸盐离子(作为四丁基铵盐)能够以SN2的方式与三甲基和三乙氧基氧离子、三氟酸甲酯和高氯酸甲酯反应，而麦克唐纳已经报告了甲苯磺酸盐氧化辅助置换碘的能力。5然而，以前还没有证明过磺酸盐离子对卤离子的非辅助SN2型置换。合成上，烷基磺酸盐通常是由相应的醇或卤化物通过磺酸银的作用制成的。6在我们的卤化物-磺酸盐交换方法中，使用了两个来自氯-碘交换的观察：需要较高的温度才能获得实用的速率(>；160℃，对于氯-i)，并且必须选择性地蒸馏出方程式1中的R‘X(1)(A)Schwesinger，R.；Fritz，H.；伯尔。1979年，112,3318.(B)Sasson，Y.；Yonovich-weas，MJ Mol.卡塔。1981年，10,357年。(C)Bidd，I.；Whiting，M.C.四面体Lett。1984，25,5949.(2)Hahn，R.C.J.Org.化学。(3)Zefirov，N.S.；Koz‘min，A.S.ACC。化学。研究结果1985，18,154(4)(A)Kevin，Dn；Lin，G.ML；Bahari，M.S.J.Chem.SoC。帕金·特伦斯。2 1981，49和其中的参考文献，(B)Kevin，DN；Anderson，S.W.；Fujimoto，E.K.in Neciphility·，Harris，J.M.，McManus，S.P.，编辑；AdvancedChemical Series 215；American Chemical Society：Washington，DC，1987；第19章。(5)MacDonald，TL；Narasimhan，NJ Org。化学。1985年，50,5000。(6)(A)埃蒙斯，WD；费里斯，AF J.Am化学。SoC。1953、75、2257(B)霍夫曼、M.R.J.化学。SoC。1965年，1251年。C&T&LVST
Recently, on finding that homogeneous quaternary am-monium halide catalyzed alkyl halide exchange1 never had been systematically explored, we used this process to de-velop a rapid, simple, solvent-free method for bromide-chloride, chloride-iodide, and bromide-iodide exchange and applied it to high-yield syntheses of certain,-hetero dihalides. 2 The ability to achieve, in particular, reversible chloride-iodide exchange encouraged us to attempt the unprecedented homogeneous conversion of alkyl halides to alkyl sulfonates; some initial successes are reported herein. Although, historically, the major role of sulfonate ions has been as leaving groups in SN1 or SN2 type processes, Zefirov noted recently3 that nucleophilicity scales such as the Swain-Scott scale “completely ignore the nucleophilic properties of... such a typical nucleofuge as the p-toluenesulfonate ion”. Indeed, Kevill4 has demonstrated the ability of arenesulfonate ions (as tetrabutylammonium salts) to reactin SN2 fashion with trimethyl-and tri-ethyloxonium ion, methyl triflate, and methyl perchlorate, and MacDonald has reported oxidatively assisted displacement of iodide by tosylate. 5 However, unassisted SN2 type displacement of halideions by sulfonate ions has not been previously demonstrated. Synthetically, alkyl sulfonates usually are made from the correspondingalcohols or from halides through the agency of silver sulfonates. 6 In our approach to halide-sulfonate exchange, two ob-servations from Cl-I exchange were used: High temper-atures were needed to achieve practical rates (> 160 C for Cl-I), and R'X in eq 1 had to be selectively distilled out (1)(a) Schwesinger, R.; Fritz, H.; Prinzbach, H. Chem. Ber. 1979, 112, 3318.(b) Sasson, Y.; Yonovich-Weias, MJ Mol. Catal. 1981, 10, 357.(c) Bidd, I.; Whiting, M. C. Tetrahedron Lett. 1984, 25, 5949.(2) Hahn, R. C. J. Org. Chem. 1988, 53, 1331.(3) Zefirov, N. S.; Koz’min, A. S. Acc. Chem. Res. 1985, 18, 154.(4)(a) Kevill, DN; Lin, G. ML; Bahari, M. S. J. Chem. Soc. Perkin Trans. 2 1981, 49 and references therein,(b) Kevill, DN; Anderson, S. W.; Fujimoto, E. K. In Nucleophilicity·, Harris, J. M., McManus, S. P., Eds.; AdvancedChemistry Series 215; American Chemical Society: Washington, DC, 1987; Chapter 19.(5) MacDonald, TL; Narasimhan, NJ Org. Chem. 1985, 50, 5000.(6)(a) Emmons, WD; Ferris, AF J. Am. Chem. Soc. 1953, 75, 2257.(b) Hoffmann,. M. R. J. Chem. Soc. 1965, 1251. c&t&lvst