- Catalytic, contra-Thermodynamic Positional Alkene Isomerization
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The positional isomerization of C═C double bonds is a powerful strategy for the interconversion of alkene regioisomers. However, existing methods provide access to thermodynamically more stable isomers from less stable starting materials. Here, we report
- Occhialini, Gino,Palani, Vignesh,Wendlandt, Alison E.
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supporting information
p. 145 - 152
(2022/01/19)
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- Palladium-Catalyzed Markovnikov Hydroaminocarbonylation of 1,1-Disubstituted and 1,1,2-Trisubstituted Alkenes for Formation of Amides with Quaternary Carbon
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Hydroaminocarbonylation of alkenes is one of the most promising yet challenging methods for the synthesis of amides. Herein, we reported the development of a novel and effective Pd-catalyzed Markovnikov hydroaminocarbonylation of 1,1-disubstituted or 1,1,2-trisubstituted alkenes with aniline hydrochloride salts to afford amides bearing an α quaternary carbon. The reaction makes use of readily available starting materials, tolerates a wide range of functional groups, and provides a facile and straightforward approach to a diverse array of amides bearing an α quaternary carbon. Mechanistic investigations suggested that the reaction proceeded through a palladium hydride pathway. The hydropalladation and CO insertion are reversible, and the aminolysis is probably the rate-limiting step.
- Yang, Hui-Yi,Yao, Ya-Hong,Chen, Ming,Ren, Zhi-Hui,Guan, Zheng-Hui
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supporting information
p. 7298 - 7305
(2021/05/26)
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- Cobalt(II)-Catalyzed Stereoselective Olefin Isomerization: Facile Access to Acyclic Trisubstituted Alkenes
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Stereoselective synthesis of trisubstituted alkenes is a long-standing challenge in organic chemistry, due to the small energy differences between E and Z isomers of trisubstituted alkenes (compared with 1,2-disubstituted alkenes). Transition metal-catalyzed isomerization of 1,1-disubstituted alkenes can serve as an alternative approach to trisubstituted alkenes, but it remains underdeveloped owing to issues relating to reaction efficiency and stereoselectivity. Here we show that a novel cobalt catalyst can overcome these challenges to provide an efficient and stereoselective access to a broad range of trisubstituted alkenes. This protocol is compatible with both mono- and dienes and exhibits a good functional group tolerance and scalability. Moreover, it has proven to be a useful tool to construct organic luminophores and a deuterated trisubstituted alkene. A preliminary study of the mechanism suggests that a cobalt-hydride pathway is involved in the reaction. The high stereoselectivity of the reaction is attributed to both a π-πstacking effect and the steric hindrance between substrate and catalyst.
- Zhang, Sheng,Bedi, Deepika,Cheng, Lu,Unruh, Daniel K.,Li, Guigen,Findlater, Michael
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supporting information
p. 8910 - 8917
(2020/12/23)
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- Highly enantioselective and anti -diastereoselective catalytic intermolecular glyoxylate-ene reactions: Effect of the geometrical isomers of alkenes
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An efficient method for the synthesis of homoallylic alcohols with high enantioselectivities and anti-diastereoselectivities via an In(III)-catalyzed intermolecular glyoxylate-ene reaction has been developed. The geometrical isomers of alkenes were shown to have different reactivities. Only the isomers of the alkenes having a proton β-cis to the substituent reacted in this catalytic system.
- Zhang, Xiang,Wang, Min,Ding, Ran,Xu, Yun-He,Loh, Teck-Peng
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supporting information
p. 2736 - 2739
(2015/06/16)
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