An unprecedented organocatalyzed aerobic oxidative Robinson annulation of 2-isocyanochalcones with active methylene ketones was developed for the expedientsynthesis of phenanthridines and hydrophenanthridinones in high to excellent yields.
An efficient reductive cyclization of o-nitrocinnamoyl compounds was achieved by employing a Hantzsch 1,4-dihydropyridine ester as a biomimetic reducing agent in the presence of catalytic palladium on carbon. This approach was successfully applied to the synthesis of substitutedquinolines. quinolines - reductive cyclization - Hantzsch ester - biomimetic reducing agent
Visible-Light Induction/Brønsted Acid Catalysis in Relay for the Enantioselective Synthesis of Tetrahydroquinolines
作者:Wenhui Xiong、Shan Li、Bo Fu、Jinping Wang、Qiu-An Wang、Wen Yang
DOI:10.1021/acs.orglett.9b01354
日期:2019.6.7
An efficient method merging Brønsted acid catalysis with visible-light induction for the highly enantioselectivesynthesis of tetrahydroquinolines has been developed. This mild process directly transforms 2-aminoenones into 2-substituted tetrahydroquinolines with excellent enantioselectivities through a relay visible-light-induced cyclization/chiral phosphoric acid-catalyzed transfer hydrogenation
s with Zn/NH4Cl gave the corresponding quinoline N‐oxides in 80–90% yields. The reaction initiated the reduction of nitro group to afford the corresponding hydroxylamine, which intramolecularly condensed and followed by dehydration to give quinoline N‐oxide. Although treatment of 2‐nitrochalcone with Zn/NH4Cl in EtOH/H2O resulted in the formation of quinoline N‐oxide in low yield, the reaction of 2‐nitrochalcone
DIPEA-Promoted Reaction of 2-Nitrochalcones with Elemental Sulfur: An Unusual Approach to 2-Benzoylbenzothiophenes
作者:Thanh Binh Nguyen、Pascal Retailleau
DOI:10.1021/acs.orglett.7b02321
日期:2017.9.15
DIPEA was found to be an excellent sulfur activator to promote the reaction of 2-nitrochalcones with elementalsulfur. A wide range of 2-benzoylbenzothiophenes was obtained as a result of a cascade of alkene C═C bond thiolation, aromatic sulfur-denitration.