Catalytic Dicyanative 5‐exo‐ and 6‐endo‐Cyclization Triggered by Cyanopalladation of Alkynes
Catalytic Dicyanative 5‐exo‐ and 6‐endo‐Cyclization Triggered by Cyanopalladation of Alkynes
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DOI：
10.1002/adsc.200900813
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发表时间：
2010-03
影响因子：
5.4
通讯作者：
S. Arai;Yuka Koike;A. Nishida
中科院分区：
文献类型：
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作者：
S. Arai;Yuka Koike;A. Nishida
研究了不同烯炔的立体选择性双氰5-外环和6-内环化反应。环化的模式由底物的结构严格控制。例如，N-烯丙基衍生物优选5-外环化，而甲基丙烯酰胺通过6-内环化转化为在α位具有四取代碳的相应内酰胺。这两种反应都包括在初始步骤中顺式氰基钯化为碳-碳三键，并且在一个操作中依次环化然后还原消除使得能够构建高度官能化的氮杂环。合适的基板和提出的机制的范围也进行了描述。
A stereoselective dicyanative 5-exo- and 6-endo-cyclization using various enynes has been investigated. The mode of cyclization is critically controlled by the structure of the substrates. For example, N-allyl derivatives prefer 5-exo-cyclization, while methacryloyl amides are transformed to the corresponding lactams with tetra-substituted carbons at the alpha-position via 6-endo-cyclization. Both reactions include syn-cyanopalladation to carbon≡carbon triple bonds in the initial step, and sequential cyclization followed by reductive elimination in one operation enables the construction of the highly functionalized nitrogen heterocycles. The scope of suitable substrates and a proposed mechanism are also described.