Intramolecular Hydroamination/Cyclization of Aminoallenes Catalyzed by Organolanthanide Complexes. Scope and Mechanistic Aspects
Intramolecular Hydroamination/Cyclization of Aminoallenes Catalyzed by Organolanthanide Complexes. Scope and Mechanistic Aspects
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DOI：
10.1021/om981037j
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发表时间：
1999-05
期刊：
影响因子：
2.8
通讯作者：
V. Arredondo;F. McDonald;T. Marks
中科院分区：
文献类型：
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作者：
V. Arredondo;F. McDonald;T. Marks
通用型有机稀土络合物Cp‘2LnCH(Tms)2(Cp’=η5-Me5C5；Ln=La，Sm，Y，Lu；tms=SiMe3)是通式为RCHCCH(CH2)NCHR‘NH2的氨基烯快速、区域选择性和高非对映选择性分子内氢胺化/环化反应的有效预催化剂，以生成相应的杂环(R=CH3，n-C3H7，n-C5H11；R’=H，CH3，n-C4H9，CH2CHCCH2；n=2，3)。生成的单取代和双取代的吡咯烷和哌啶具有α-烯基官能团，可用于进一步的合成操作。动力学和力学数据平行于有机稀土介导的分子内氨基烯烃和氨基炔氢胺化/环化反应，这意味着在Ln−N键中插入翻转限制的联烯，随后生成的Ln−C键快速质子化。在3个或3个以上的半衰期内，反应速率在[氨基烯]中为零级，在[催化剂]中为一级。单取代氨基联烯(R=H；R‘=H，CH3；n=1)的氢胺化/环化反应.
Organolanthanide complexes of the general type Cp‘2LnCH(TMS)2 (Cp‘ = η5-Me5C5; Ln = La, Sm, Y, Lu; TMS = SiMe3) serve as effective precatalysts for the rapid, regioselective, and highly diastereoselective intramolecular hydroamination/cyclization (IHC) of aminoallenes having the general formula RCHCCH(CH2)nCHR‘NH2 to yield the corresponding heterocycles (R = CH3, n-C3H7, n-C5H11; R‘ = H, CH3, n-C4H9, CH2CHCH2CH2; n = 2, 3). The mono- and disubstituted pyrrolidines and piperidines produced bear an α-alkenyl functionality available for further synthetic manipulation. Kinetic and mechanistic data parallel organolanthanide-mediated intramolecular aminoalkene and aminoalkyne hydroamination/cyclization, implying turnover-limiting allene insertion into the Ln−N bond followed by rapid protonolysis of the resulting Ln−C bond. The reaction rate is zero-order in [aminoallene] and first-order in [catalyst] over 3 or more half-lives. Hydroamination/cyclization of monosubstituted aminoallenes (R = H; R‘ = H, CH3; n = 1...