REACTION OF DIENES WITH CHLOROSULFONYL ISOCYANATE
REACTION OF DIENES WITH CHLOROSULFONYL ISOCYANATE
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DOI：
10.1021/jo00818a025
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发表时间：
1971-01-01
影响因子：
3.6
通讯作者：
MEYER, WC
中科院分区：
文献类型：
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作者：
MORICONI, EJ;MEYER, WC
氯磺酰基异氰酸酯（CSI）可能作为2组分在与T2 a体系的协同反应中起反相作用。它在低温下加成到共轭二烯如1，3-丁二烯、异戊二烯、2，3-二甲基-1，3-丁二烯、顺式，铁-1，3-戊二烯混合物和铁-1，3-和反式，反式-2，4-己二烯中。β-内酰胺产物是马尔可夫尼科夫取向的1，2-环加合物，其中CSI已添加到末端双键。在任何情况下都没有观察到对称性允许的T4 S + T2 a反应。这些最初形成的N-氯磺酰基-β-内酰胺热重排为N-和0-1，4环加合物。提出了可供选择的逐步协调机制。N-氯磺酰基-β-内酰胺在丙酮-水中的碱性水解通常得到NH 2-氮杂环丁酮。在甲醇中，溶剂参与碱性水解导致环断裂和N-氨基（N-磺酸）羧酸的双酯的形成。由于这两个水解过程可能都是通过OH-取代Cl-开始的，中间体磺酸必须被甲醇作为磺酸酯捕获。在2-氮杂环丁烷酮的NMR谱中，观察到NH和C-3质子之间的四键耦合。在4-取代的2-氮杂环丁烷酮中，J的大小对于C-3质子反式到C-4取代基是最大的，而在4，4-二取代的2-氮杂环丁烷酮中，C-3质子反式到C-4处的较大取代基具有更大的J值，并且也比顺式质子出现更远的低场。氯磺酰基异氰酸酯（CSI）与某些不饱和体系的热允许T2 a + T2 a3环加成反应45是CSI与共轭二烯之间形成1，2环加成物。6连接到CSI中累积双键的极性氯磺酰基增强异氰酸酯基团的反应性，使得碳原子是强亲电的。6因此，CSI应该与烯酮一样有利地构成，以在与T2 a组分的协同反应中发挥反作用。
Chlorosulfonyl isocyanate (CSI) may play an antarafacial role as the 2 component in concerted reactions with T2a systems. It does so in additions at low temperature to such conjugated dienes as 1, 3-butadiene, isoprene, 2, 3-dimethyl-l, 3-butadiene, the cis, irons-1, 3-pentadiene mixture, and irons-1, 3-and trans, trans-2, 4-hexadiene. The/3-lactam products are Markovnikov-oriented 1, 2-cycloadducts in which CSI has added to the terminal double bond. In no instance was the symmetry-allowed T4S+ T2a reaction observed. These initially formed N-chlorosulfonyl-^-lactams thermally rearrange to N-and 0-1, 4 cycloadducts. Alternative stepwise and concerted mechanisms are proffered. Alkaline hydrolysis of the N-chlorosulfonyl-/3-lactams in acetone-water conventionally afford NH 2-azetidinones. In methanol, solvent participation in the alkaline hydrolysis led to ring cleavage and the formation of bis esters of/3-amino (A7-sulfonic acid) carboxylie acids. Since both hydrolytic processes probably commence by displacement of Cl- by OH-, the intermediate sulfonic acid must be trapped by the methanol as the sulfonate ester. In the nmr spectra of 2-azetidinones, four-bond coupling was observed between NH and C-3 protons. In 4-substituted 2-azetidinones, the magnitude of J was largest to the C-3 proton trans to the C-4 substituent, while, in 4, 4-disubstituted 2-azetidinones, the C-3 proton trans to the larger substituent at C-4 has the greater J value and also appears further downfield than the cis proton.Among the compelling pieces of evidence for the (near) concerted, thermally allowed T2a+ T2a3 cyclo-addition of chlorosulfonyl isocyanate (CSI) to certain unsaturated systems4 5is the formation of 1, 2 cycloadducts between CSI and conjugated dienes. 6 The polar chlorosulfonyl group attached to the cumulative double bond in CSI enhances the reactivity of the isocyanate group such that the carbon atom is strongly electrophilic. 6 Thus CSI should be just as favorably constituted as ketenes toplay an antarafacial role as the T2a component in concerted reactions with