| 铑催化的1,6-烯炔环异构化反应研究（英文） |
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| 作者姓名： | 童晓峰 张兆国 张绪穆 |
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| 作者单位： | 中国科学院上海有机化学研究所金属有机化学国家重点实验室，上海 200032 |
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| 摘 要： | 对铑催化的1,6-烯炔环异构化反应进行了研究，这类反应具有较广的底物适应范围，在转化过程中，卤素发生了分子内转移。这类反应提供了一条新的立体选择性合成具有α-氯烯基结构的丁内酯、丁内酰胺、四氢呋喃、吡喃以及五元碳环等分子的方法。发展了两种不同的催化剂体系，即阳离子催化剂体系和中性催化剂体系。阳离子催化剂体系仅能催化顺式烯炔底物的环异构化，相反中性催化剂体系不但能催化顺反烯炔底物的环异构化，而且具有更广的底物适应范围。利用各种烯炔异构体，通过合适的控制实验对反应机理进行了研究。提出了涉及π-烯丙基铑中间体的可能机理，并且利用该机理对一些反应现象进行了解释。最后利用Suzuki偶联反应对产物进行了衍生。
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| 关 键 词： | 铑催化 6-烯炔环异构化 分子内卤素迁移 |
Rhodium-Catalyzed Cycloisomerization of 1,6-Enynes with an Intramolecular Halogen Shift |
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| Authors: | TONG Xiao-Feng ZHANG Zhao-Guo ZHANG Xu-Mu |
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| Institution: | State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Science, 354 Fenglin Rd., Shanghai 200032, China and Department of Chemistry, the Pennsylvania State University, University Park, PA 16801, USA |
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| Abstract: | A Rhodium(I)-species catalyzed cycloisomerization reaction of a wide spectrum of 1,6-enynes with an unusual intramolecular halogen shift was investigated. This Rh-catalyzed enyne cyclization reaction represents a new process for the synthesis of stereodefined α-halomethylene-γ-butyrolactones, lactams, tetrahydrofurans, pyrrolidines and cyclopentanes. Coordinatively unsaturated rhodium species (Rh(COD)Cl]2 + dppb + AgSbF6) only catalyzes the reaction with enyne substrates bearing a Z-form double bond. While neutral rhodium species (RhCl(PPh3)3) could catalyze enyne substrates bearing a Z- or E-form double bond to form the desired products and has a wider substrate scopes. The mechanism of the reaction was studied by the employment of control experiments with different enyne isomers and a π-allyl rhodium intermediate was suggested to explain the formation of the cyclic products with intramolecular halogen shift. Further transformation of the halo-alkenyl species can be readily achieved through transition metal-catalyzed Suzuki cross-coupling reactions. |
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| Keywords: | Rhodium-catalyzed Cycloisomerization of 1 6-enynes Intramolecular Halogen Shift |
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