Exoselective 1,3-dipolar [3 + 6] cycloaddition of azomethine ylides with 2-acylcycloheptatrienes: stereoselectivity and mechanistic insight.
Exoselective 1,3-dipolar [3 + 6] cycloaddition of azomethine ylides with 2-acylcycloheptatrienes: stereoselectivity and mechanistic insight.
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DOI：
10.1021/acs.orglett.5b00011
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发表时间：
2015-02
期刊：
影响因子：
5.2
通讯作者：
Zhao-Lin He;F. Sheong;Qing‐Hua Li;Zhenyang Lin;Chun‐Jiang Wang
中科院分区：
文献类型：
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作者：
Zhao-Lin He;F. Sheong;Qing‐Hua Li;Zhenyang Lin;Chun‐Jiang Wang
以Cu（I）/（S，R（p））-PPF-NHMe配合物为催化剂，实现了偶氮甲碱叶立德与2-酰基环庚三烯的高外选择性1，3-偶极[3 + 6]环加成反应，以良好的产率和优异的立体选择性控制得到了多种具有多官能团的桥联哌啶。理论计算表明，这种外选择性的[3 + 6]成环的逐步机制，这占了显着的特点，这种成环：所有较大的取代基占据轴向位置的六元椅状构象的哌啶环。
A highly exo-selective 1,3-dipolar [3 + 6] cycloaddition of azomethine ylides with 2-acylcycloheptatrienes was realized with a Cu(I)/(S,R(p))-PPF-NHMe complex as the catalyst, leading to a diverse range of bridged piperidines with multiple functionalities in good yield with excellent stereoselectivity control. Theoretical calculations indicated a stepwise mechanism for this exo-selective [3 + 6] annulation, which accounts for the remarkable feature of this annulation: all of the larger substituent groups occupy the axial positions in the six-membered chairlike conformation of the piperidine ring.