REACTIONS OF TRIALKOXYSULFURANES (ORTHOSULFINATES) WITH TRIFLUOROMETHANESULFONIC ACID - 1ST ISOLATION OF A DIALKOXYSULFONIUM SALT AND MECHANISMS OF DECOMPOSITION OF SUCH SALTS
REACTIONS OF TRIALKOXYSULFURANES (ORTHOSULFINATES) WITH TRIFLUOROMETHANESULFONIC ACID - 1ST ISOLATION OF A DIALKOXYSULFONIUM SALT AND MECHANISMS OF DECOMPOSITION OF SUCH SALTS
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DOI：
10.1021/ja00455a031
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发表时间：
1977-01-01
影响因子：
15
通讯作者：
MARTIN, JC
中科院分区：
文献类型：
--
作者：
ASTROLGES, GW;MARTIN, JC
合成了三烷氧基呋喃La、Lb和Lc。它们与三氟甲磺酸(三氟酸)反应，分别得到三氟酸酯2a和2b和三氟化二烷氧基硫酸盐10c，这是第一个分离的二烷氧基硫磺酸盐。根据氧-18标记研究和反应的相对速率，提出了高能氟化碳离子在硫代离基电离反应中生成三氟酸酯2a和2b的速率控制机制。与其他硫烷和烷氧基硫的化学进行了比较，最近报道了二烷氧基和三烷氧基硫烷与双功能试剂反应的有趣的差异。1在这里，我们描述了三氟甲磺酸(三氟甲磺酸)与几个尝试的烷氧基呋喃的反应，并将其与三氟甲磺酸与杂环2和环3二烷氧基呋喃反应中所见的烷氧基硫离子的形成进行了对比。虽然烷氧基硫酸盐也可以很容易地通过亚硫醚的烷基化反应来制备，但最近才在溶液5中检测到4个二烷氧基硫离子是热不稳定的氟磺酸盐或在高浓度三氟甲酸甲酯存在下稳定的三氟离子。在这里，我们首次分离出一种二烷氧基硫酸盐，并研究了其他被认为是三烷氧基硫-呋喃与三氟酸反应的中间产物的二烷氧基硫离子的分解机理。
Trialkoxysulfuranes la, lb, and lc are synthesized. Their reactions with trifluoromethanesulfonic (triflic) acid give, respectively, triflate esters 2a and 2b and dialkoxysulfonium triflate 10c, the first isolated dialkoxysulfonium salt. From oxy-gen-18 labeling studies and relative rates of reactions, a mechanism involving rate-determining formation of high energy fluo-rinated carbonium ions, in an ionization reaction involving a sultine leaving group, is proposed for the formation of triflate es-ters 2a and 2b. Comparisons with other sulfuraneand alkoxysulfonium chemistry are advanced.Interesting differences between the reactions of dialkoxy-and trialkoxysulfuranes with bifunctional reagents have re-cently been reported. 1 Here we describe the reactions of tri-fluoromethanesulfonic acid (triflic acid) with several trial-koxysulfuranes and constrast this to the alkoxysulfonium ion formation seen in the reactions of triflic acid with acyclic2 and cyclic3 dialkoxysulfuranes. While alkoxysulfonium salts can also easily be prepared by alkylation of sulfoxides, 4 dialkoxysulfonium ions have only recently been detected in solution5 as thermally unstable fluorosulfonates or as triflates stable in the presence of a high concentration of methyl triflate. Here we report the first isolation of a dialkoxysulfonium saltand the mechanism of decomposition of other dialkoxysulfonium ions postulated to be intermediates in reactions of trialkoxysul-furanes with triflic acid.