- Bisoxazoline-pincer ligated cobalt-catalyzed hydrogenation of alkenes
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The efficient and atom economical hydrogenation of alkenes using a novel bisoxazoline ligated cobalt complex has been developed. The hydrogenation of a variety of alkenes containing electron neutral and electron-donating groups proceeds in high yield, whi
- Ritz, Mikhaila D.,Parsons, Astrid M.,Palermo, Philip N.,Jones, William D.
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- 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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p. 10484 - 10488
(2020/04/29)
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- Reaction of Piperidine with Carbonyl Compounds Over Alumina
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A mixture of a carbonyl compound with piperidine dissolved in benzene, when passed over alumina at 420 deg C gives 3-alkylpyridine in 10-40percent yield.Mechanism of the reaction is discussed.
- Jayamani, M.,Ananthan, S.,Pillai, C.N.
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p. 131 - 132
(2007/10/02)
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- Reactions of 1,4-Bis(trimethylsilyl)-1,4-dihydropyridines with Carbonyl Compounds: A New Method for Regioselective Synthesis of 3-Alkylpyridines
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A new method for the alkyl group introduction at the 3-position of pyridines is described: Reductive disilylation of pyridine, its 2-methyl, 3-methyl, and 4-methyl derivatives affords the corresponding 1,4-disilyl-1,4-dihydropyridines.Tn the presence of a catalytic amount of tetrabutylammonium fluoride, these dihydropyridines smoothly react with a variety of aldehydes and ketones to give 3-alkylpyridines.
- Tsuge, Otohiko,Kanemasa, Shuji,Naritomi, Toshio,Tanaka, Junji
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p. 1497 - 1504
(2007/10/02)
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- REGIOSELECTIVE ALKYL GROUP INTRODUCTION AT THE 3-POSITION OF PYRIDINE VIA 1,4-BIS(TRIMETHYLSILYL)-1,4-DIHYDROPYRIDINE
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The reaction of 1,4-bis(trimethylsilyl)-1,4-dihydropyridine with aldehydes and ketones in the presence of tetrabutylammonium fluoride offers a convenient method for the preparation of 3-alkylpyridines.
- Tsuge, Otohiko,Kanemasa, Shuji,Naritomi, Toshio,Tanaka, Junji
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p. 1255 - 1258
(2007/10/02)
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