- Photoenzymatic Hydrogenation of Heteroaromatic Olefins Using ‘Ene’-Reductases with Photoredox Catalysts
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Flavin-dependent ‘ene’-reductases (EREDs) are highly selective catalysts for the asymmetric reduction of activated alkenes. This function is, however, limited to enones, enoates, and nitroalkenes using the native hydride transfer mechanism. Here we demonstrate that EREDs can reduce vinyl pyridines when irradiated with visible light in the presence of a photoredox catalyst. Experimental evidence suggests the reaction proceeds via a radical mechanism where the vinyl pyridine is reduced to the corresponding neutral benzylic radical in solution. DFT calculations reveal this radical to be “dynamically stable”, suggesting it is sufficiently long-lived to diffuse into the enzyme active site for stereoselective hydrogen atom transfer. This reduction mechanism is distinct from the native one, highlighting the opportunity to expand the synthetic capabilities of existing enzyme platforms by exploiting new mechanistic models.
- Biegasiewicz, Kyle F.,Black, Michael J.,Chung, Megan M.,Hyster, Todd K.,Meichan, Andrew J.,Nakano, Yuji,Sandoval, Braddock A.,Zhu, Tianyu
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supporting information
p. 10484 - 10488
(2020/04/29)
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- Pyridine-directed asymmetric hydrogenation of 1 1-diarylalkenes
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Highly enantioselective pyridine-directed rhodium-catalyzed asymmetric hydrogenation of challenging 1 1-diarylalkenes is achieved by using [Rh(NBD)DuanPhos]BF4 as a precatalyst. Various types of 2-pyridine substituted 1 1-diarylalkenes could be hydrogenated with good to excellent enantioselectivities which provide an efficient route to the synthesis of pharmaceutically and biologically active compounds containing a 2-pyridyl ethane unit.
- Yang, Hailong,Wang, Erfei,Yang, Ping,Lv, Hui,Zhang, Xumu
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supporting information
p. 5062 - 5065
(2017/11/07)
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- Copper-catalysed oxidative Csp3-H methylenation to terminal olefins using DMF
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A copper-catalysed direct oxidative Csp3-H methylenation to terminal olefins using DMF as one carbon source was developed. In this reaction, various functional groups were well tolerated, thus providing a simple way to construct arylvinylketones and arylvinylpyridines. The preliminary mechanistic investigations revealed that CH2 was from DMF (N-CH3).
- Liu, Jianming,Yi, Hong,Zhang, Xin,Liu, Chao,Liu, Ren,Zhang, Guoting,Lei, Aiwen
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supporting information
p. 7636 - 7638
(2014/07/08)
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- Copper-catalyzed α-methylenation of benzylpyridines using dimethylacetamide as one-carbon source
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The direct α-methylenation of benzylpyridines was achieved using N,N-dimethylacetamide (DMA) as a one-carbon source under copper catalysis. An intermediary species was detected at an early stage, and a possible mechanism was proposed. Additionally, α-oxygenation and dimerization of benzylpyridines could also be performed efficiently.
- Itoh, Masaki,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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supporting information
p. 2050 - 2053
(2014/05/06)
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- An efficient coupling of N-tosylhydrazones with 2-halopyridines: Synthesis of 2-α-styrylpyridines endowed with antitumor activity
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The synthesis of 2-α-styrylpyridines has been carried out by using the coupling of polyoxygenated N-tosylhydrazones with various 2-halopyridines. We demonstrated that the use of a catalytic amount of PdCl2(MeCN) 2 in combination with a bidentate ferrocene DPPF or a monodentate alkyl phosphine tBu2MeP-HBF4 constitutes an efficient protocol for this coupling, providing 2-α-styrylpyridines 2 in satisfactory to good yields. Among several polyoxygenated derivatives 2 evaluated, compound 2aa was found to exhibit excellent antiproliferative and antimitotic activities comparable to that of the reference compound isoCA-4. The Royal Society of Chemistry 2013.
- Lawson, Marie,Hamze, Abdallah,Peyrat, Jean-Fran?ois,Bignon, Jér?me,Dubois, Joelle,Brion, Jean-Daniel,Alami, Mouad
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p. 3664 - 3673
(2013/06/26)
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