Pd(0)-Catalyzed Asymmetric 7-Endo Hydroacyloxylative Cyclization of 1,6-Enyne Enabled by an Anion Ligand-Directed Strategy,Journal of the American Chemical Society

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Pd(0)-Catalyzed Asymmetric 7-Endo Hydroacyloxylative Cyclization of 1,6-Enyne Enabled by an Anion Ligand-Directed Strategy
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2023-01-13 , DOI: 10.1021/jacs.2c12756
Ming Dong _{1,

2} , Linjun Qi ₁ , Jinlong Qian ₁ , Shuling Yu ₁ , Xiaofeng Tong _{1,

2}

Affiliation

Despite diversity in reaction mechanisms, the palladium-catalyzed cyclization of 1,6-enyne generally proceeds in a 5-exo manner. Herein, we report the development of a Pd(0)-catalyzed hydroacyloxylative cyclization of 1,6-enyne in either 7-endo-trig or 6-exo-trig fashion when paired with an appropriate dihaloacetic acid reactant, such as F₂HCCO₂H and Cl₂HCCO₂H. Using the combination of Pd₂(dba)₃ and a chiral phosphine ligand, the hydroacyloxylative cyclization of 1,6-enyne bearing a 1,1-disubstituted alkene moiety readily gives highly enantiopure seven-membered heterocycles while the reaction of those having a 1,2-disubstituted alkene affords six-membered rings with moderate enantioselectivity. Preliminary experimental studies suggest a reaction mechanism featuring an unusual E-to-Z vinyl-Pd(II) isomerization and alkene trans-oxypalladation, which is proven to be governed by the rationally selected carboxylate.

中文翻译：

Pd(0)-催化的 1,6-烯炔的不对称 7-Endo Hydroacyloxylative 环化由阴离子配体导向策略实现

尽管反应机制多种多样，但钯催化的 1,6-烯炔环化通常以 5-外切方式进行。在此，我们报告了在与适当的二卤乙酸反应物（例如 F ₂ HCCO ）配对时，Pd(0) 催化的 1,6-烯炔以 7-内-触发或 6-外-触发方式的加氢酰氧基化环化的发展₂ H和Cl ₂ HCCO ₂ H.结合使用Pd ₂ (dba) ₃和手性膦配体，带有 1,1-二取代烯烃部分的 1,6-烯炔的加氢酰氧基化环化很容易得到高度对映体纯的七元杂环，而具有 1,2-二取代烯烃的那些反应提供六元环具有适度的对映选择性。初步实验研究表明，反应机制具有不寻常的E -to- Z乙烯基-Pd (II) 异构化和烯烃反式氧钯化反应，这被证明是由合理选择的羧酸盐控制的。

更新日期：2023-01-13

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