Improved Synthesis of Cyclohexane-Backbone Iridium-Complexes of Quinoline-Phosphine and Their Applications in Asymmetric Hydrogenation
摘要:
The iridium-complexes 3 and 4 with cyclohexane-backbone derived from quinoline were easily synthesized. The key step is cis/trans stereoselective reduction of 2-(quinolin-2-yl)cyclohexanone 5 to trans-2-(quinolin-2-yl)cyclohexanol 6 using Al(Oi-Pr)(3)/i-PrOH and the following diastereomeric optical resolution of racemic 6 using 0.50 equiv (S)-mandelic acid in EtOAc. These complexes were used in the asymmetric hydrogenation of (E)-1,2-diphenylpropene with up to 13% ee/48% cony. using 3 and 35% ee/9% cony. using 4. For the hydrogenation of (2H-chromen-3-yl)methanol, up to 80% ee/95% yield and 72% ee/96% yield were achieved. The same configuration of the products by using 3 and 4 suggested that the absolute configuration was controlled by the configuration of the stereogenic quinolinyl-bearing carbon of the complexes.
Intramolecular Desulfitative Coupling: Nickel-Catalyzed Transformation of Diaryl Sulfones into Biaryls via Extrusion of SO<sub>2</sub>
作者:Fumiya Takahashi、Keisuke Nogi、Hideki Yorimitsu
DOI:10.1021/acs.orglett.8b02972
日期:2018.10.19
As a new transformation of organosulfur compounds, intramolecular desulfitative coupling of diaryl sulfones to the corresponding biaryls has been developed with the aid of nickel–NHC catalysts. This catalytic elimination of SO2 was also applicable to alkenyl aryl sulfone to furnish the corresponding alkenyl arene.
Reductive Cyclization of <i>o</i>-Nitrophenyl Propargyl Alcohols: Facile Synthesis of Substituted Quinolines
作者:Matthew J. Sandelier、Philip DeShong
DOI:10.1021/ol0710921
日期:2007.8.1
Reduction of secondary and tertiary o-nitrophenyl propargyl alcohols followed by acid-catalyzed Meyer-Schuster rearrangement gave 2-substituted and 2,4-disubstituted quinolines, respectively. Tertiary propargyl alcohols gave excellent yields of the quinoline derivative, while the yields of quinolines were slightly reduced when secondary propargyl alcohol derivatives were utilized.
A rapid and efficient SnCl2·2H2O mediated synthesis of quinolines and indazoles has been developed using A3-coupling followed by reductive cyclization. The key highlights are the formation of quinoline in a one-pot fashion and indazole through N–N bond formation.