Selective Debromination and α-Hydroxylation of α-Bromo Ketones Using Hantzsch Esters as Photoreductants
作者:Jaehun Jung、Jun Kim、Gyurim Park、Youngmin You、Eun Jin Cho
DOI:10.1002/adsc.201500734
日期:2016.1.7
Two transformations initiated by photoinduced one‐electrontransfer to α‐bromo ketones have been demonstrated. Hantzsch esters donate one electron to α‐bromo ketones under photoirradiation, promotingreductive debromination. Subsequent reactions of the resulting radical species of the ketones with molecular oxygen and Hantzsch esters lead to α‐hydroxylation or debromination, respectively. The relative
1-Methylimidazolium trifluoroacetate [Hmim]Tfa: Mild and efficient Brønsted acidic ionic liquid for Hantzsch reaction under microwave irradiation
作者:JEMIN R AVALANI、DEVJI S PATEL、DIPAK K RAVAL
DOI:10.1007/s12039-012-0306-5
日期:2012.9
Onepotsynthesis of 1,4-dihydropyridine derivatives was achieved via condensation of various β-ketoesters with aromatic/aliphatic aldehydes and ammonium acetate. The reaction was catalysed by a stable and reusable Brønsted acidic ionic liquid (IL), 1-methyl-imidazolium trifluoroacetate ([Hmim]Tfa), undermicrowave (MW) irradiation. The synergistic combination of MW with IL can potentially go a long
Laccase-catalyzed oxidation of Hantzsch 1,4-dihydropyridines to pyridines and a new one pot synthesis of pyridines
作者:Heba T. Abdel-Mohsen、Jürgen Conrad、Uwe Beifuss
DOI:10.1039/c2gc35950b
日期:——
laccase-catalyzed oxidation of 1,4-dihydropyridines to pyridines using aerial O2 as the oxidant exclusively delivers pyridines with yields up to 95% under mild reaction conditions. Combination of the Hantzsch 1,4-dihydropyridine synthesis with the newly developed laccase-catalyzed oxidation forms the basis of a facile and environmentally benign method for the synthesis of pyridines in one pot.
Donor–Acceptor Complex Enables Alkoxyl Radical Generation for Metal‐Free C(sp
<sup>3</sup>
)–C(sp
<sup>3</sup>
) Cleavage and Allylation/Alkenylation
作者:Jing Zhang、Yang Li、Ruoyu Xu、Yiyun Chen
DOI:10.1002/anie.201707171
日期:2017.10.2
The alkoxyl radical is an essential and prevalent reactive intermediate for chemical and biological studies. Here we report the first donor–acceptor complex‐enabled alkoxyl radical generation under metal‐free reaction conditions induced by visible light. Hantzsch ester forms the key donor–acceptor complex with N‐alkoxyl derivatives, which is elucidated by a series of spectrometry and mechanistic experiments