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首页> 外文期刊>Chemistry: A European journal >The Hetro-Diels-Alder Adition of Sulfur Dioxide to 1-Fluorobuta-1,3-dienes: The Sofa Conformations Preferred by 6-Fluorosultines (6-Fluoro-3,6-dihydro-1,2-oxathiin-2-oxides) Fnjoy Enthalpic and Conformational Anomeric Effects
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The Hetro-Diels-Alder Adition of Sulfur Dioxide to 1-Fluorobuta-1,3-dienes: The Sofa Conformations Preferred by 6-Fluorosultines (6-Fluoro-3,6-dihydro-1,2-oxathiin-2-oxides) Fnjoy Enthalpic and Conformational Anomeric Effects

机译：二氧化硫与1-Fluorobuta-1,3-dienes的Hetro-Diels-Alder加成：6-Fluorosultines（6-Fluoro-3,6-dihydro-1,2-oxathiin-2-oxides）首选的沙发构型Fnjoy焓和构象端基效应

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摘要

The reactivity of (E)-and (Z)-1-fluorobuta-1,3-diene ((E)-and (Z)-11), 2-fluorobutadiene (12), (E)-and (Z)-1-(fluoromethylidene)-2-methylidenecyclohexane ((E)-and (Z)-13) toward SO_2 has been explored and compared with that of (Z)-and (E)-1-(fluoromethylidene)-2-methylidene-3,4-dihydronaphthalaene ((Z)-8 nd (E)-8). In agreement with quantum calcultions. 12 is unreactive toward SO_2 (no cycloaddition, only polymerization), whereas (E)-1-fluoro-1,3-dienes react more rapidly than their (Z)-isomers to give the corresponding 6-fluorosultines following the endo (Alder rule) mode to hetero-Diels-Alder addition. No sulfolene has been observed following the cheletropic mode of addition with the fluorodienes, in contrat to other substituted dienes. In agreement with the calculations, cis-2-fluoro-3,4-oxathiabenzobicyclo[4.4.0]dec-1(6),9-diene-4-oxide (cis-9, the sultine obtiaend by SO_2 addition to (Z)-8 under conditions of kinetic control) adopts a sofa conformatin with the oxygen atom of the ring lying in the average plane of the four carbon atoms of its sultine moiety when it is in the crystlaline state at -100deg c. A similar sofa conformation was found for its trans-isomer, trns-9, obtained by isomerization of cis-9 or by hetero-Diels-Alder addition of SO_2 to (E)-8. Experiments (equilibrium constant for hetero-Diels-Alder additions, bond lengths, and bond angles in crystalline fluorosultines cis-9 and trans-9) and high-levle quantum calculations on cis-and trans-6-fluoro-3,6-dihydro-1,2-oxathiin-2-oxide (cis-and trans-20) confirm the existenece of a stabilizing, enthalpic, anomeric (gem-disubstitution by sulfinyloxy and fluoro groups)_ effect, which is itnerpreted in terms of (loene pair) n(O1)->#sigma#~*(C-F) hyperconjugative interactions. This efect is strongest in the ment of the #sigma#(O1,S2) and #sigma#(C6,F) bonds. The calculations suggest also that n(O1)->#sigma#~*(S2,O2'), #pi#~*(S=O), and n(S2)->#sigma#~*(O1,C6) interactions intervene and affect the relatie stability of the conformers (sofa, boat, pseudochair) found for 6-fluorosultines cis-and trans-20.
机译：（E）和（Z）-1-氟丁1,3-二烯（（E）和（Z）-11），2-氟丁二烯（12），（E）和（Z）-的反应性已经研究了针对SO_2的1-（氟亚甲基）-2-亚甲基环己烷（（E）-和（Z）-13）并与（Z）-和（E）-1-（氟亚甲基）-2-亚甲基- 3,4-二氢萘（（Z）-8和（E）-8）。与量子力学一致。 12对SO_2无反应（无环加成，仅聚合），而（E）-1-氟-1,3-二烯的反应比其（Z）异构体反应更快，遵循内切法给出相应的6-氟磺嘌呤（Alder规则） ）模式添加到杂项Diels-Alder加法。与其它取代的二烯相反，在与氟代二烯的增溶加成模式下未观察到环丁砜。与计算结果一致，顺式-2-氟-3,4-氧杂噻吩并双环[4.4.0] dec-1（6），9-二烯-4-氧化物（顺式9，通过SO_2加入到（Z ）-8在动力学控制的条件下）采用一种沙发保形素，其环的氧原子在-100℃下处于晶硅酸盐状态时，处于其磺酰部分的四个碳原子的平均平面内。对于其反式异构体trns-9，发现了类似的沙发构象，该构型是通过顺式9的异构化或通过将SO_2杂Diels-Alder加至（E）-8而获得的。实验（结晶氟磺胺类顺式9和反式9中杂Diels-Alder的平衡常数，键长和键角）和顺式和反式-6-氟-3,6-二氢的高能级量子计算-1,2-氧杂ath啶-2-氧化物（顺式和反式20）证实存在稳定，焓，异头物（亚磺酰氧基和氟基团引起的宝石二取代）_效应，根据（烯对） ）n（O1）->＃sigma＃〜*（CF）超共轭相互作用。这种影响在＃sigma＃（O1，S2）和＃sigma＃（C6，F）键的作用中最强。该计算还表明n（O1）->＃sigma＃〜*（S2，O2'），＃pi＃〜*（S = O）和n（S2）->＃sigma＃〜*（O1，C6 ）的相互作用会干预并影响6-氟磺胺类顺式和反式20顺式异构体（沙发，船，假椅）的相对稳定性。

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