CHROMOUS CHLORIDE PROMOTED CYCLIZATION OF OLEFINIC N-CHLORO AMIDES - SYNTHESIS OF NITROGEN-HETEROCYCLES
CHROMOUS CHLORIDE PROMOTED CYCLIZATION OF OLEFINIC N-CHLORO AMIDES - SYNTHESIS OF NITROGEN-HETEROCYCLES
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DOI：
10.1021/jo00413a027
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发表时间：
1978-01-01
影响因子：
3.6
通讯作者：
WAEGELL, B
中科院分区：
文献类型：
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作者：
LESSARD, J;COTE, R;WAEGELL, B
比较了氯化铬促进了各种烯烃n -氯- iv -甲基羧酰胺的环化反应与类似的n -氯- iv -烯基乙酰酰胺的环化反应。除了一种情况外，其他情况下，前者的收益率都高于后者。IV-chloro-JV-methylcycloheptenecarboxamide （13b）的高环化率（95%）值得注意，因为它形成了一个六元环，与类似的N-chloro-IV-cycloheptenylacetamide （16b）的环化失败形成对比。许多氮杂环化合物以优异的收率合成，包括偶氮金刚烷衍生物28和偶氮金刚烷衍生物30和31。以iv -氯羧酰胺26b为原料制备azatwistanone衍生物的尝试失败。与几种iv -氯酰胺的光化学和过氧化环化反应的比较表明，氯化铬法通常能获得更好的收率。从以下几个方面对反应机理进行了探讨：比较了四氯羧胺和四氯乙酰胺的反应活性；分子内双键加成和分子内烯丙基氢抽离反应中酰胺自由基（未络合或未络合）相对反应活性的比较立体化学;自由基链式反应转移步骤的性质。
The chromous chloride promoted cyclization of a variety of olefinic N-chloro-lV-methyl carboxamides was com-pared to the cyclization of the analogous N-chloro-IV-alkenylacetamides. In all cases but one, the yields were higher with the former thanwith the latter. The high yield of cyclization (95%) of IV-chloro-JV-methylcycloheptenecarboxamide (13b) is noteworthy since a six-membered ring is formed and contrasts with the failure of the analogous N-chloro-IV-cycloheptenylacetamide (16b) to cyclize. A number of nitrogen heterocycles were synthesized in good to excellent yields, including the azahomoadamantanone derivative 28 and the azaadamantane derivatives 30 and 31. An attempt to prepare an azatwistanone derivative from IV-chloro carboxamide 26b failed. Comparison with photo-chemical and peroxide cyclizations of a few IV-chloro amides showed that better yields were usually obtained with the chromous chloride method. The reaction mechanism is discussed from the following points of view: comparison of reactivity of the IV-chloro carboxamides and IV-chloro acetamides; comparison of the relative reactivity of amido radicals (complexed or not) in intramolecular addition to double bonds and intramolecular allylic hydrogen ab-straction; stereochemistry; nature of the transfer step of the radical chain reaction.