Asymmetric Michael addition reactions catalyzed by a novel upper-rim functionalized calix[4]squaramide organocatalyst
作者:Ke Yang、Zhiyan Ma、Hong-Xiao Tong、Xiao-Qiang Sun、Xiao-Yu Hu、Zheng-Yi Li
DOI:10.1016/j.cclet.2020.02.057
日期:2020.12
Abstract A novel upper-rim functionalizedcalix[4]squaramide organocatalyst bearing bis-squaramide and cyclohexanediamine scaffolds was designed and prepared to catalyse a serial of asymmetric Michael addition of 1,3-dicarbonyl compounds to α,β-unsaturated carbonyl compounds in high yields (up to 99 %) and good to excellent enantiomeric excesses (up to 99% ee). The comparative experiments indicated
Some novel prolinal dithioacetal derivatives have been synthesized and applied as the organocatalysts for the direct Michaeladdition of ketones and aldehydes to nitroalkenes. High enantioselectivities and diastereoselectivities have been obtained in both organic and aqueous media (dichloromethane, water, or brine).
Visible-light-enabled denitrative carboxylation of β-nitrostyrenes: a direct photocatalytic approach to cinnamic acids
作者:Shubhangi Tripathi、Lal Dhar S. Yadav
DOI:10.1039/c7nj04578f
日期:——
The first workable application of β-nitrostyrenes and CBr4 as coupling partners for a highly stereoselective synthesis of (E)-cinnamic acids under visible light photoredox catalysis is reported. The reaction involves a radical denitrative tribromomethylation/hydrolysis cascade to afford (E)-cinnamic acids in excellent yields at room temperature in a one-pot procedure. Moreover, the implementation of
Preparation of Pyrrolidine-Based PDE4 Inhibitors via Enantioselective Conjugate Addition of α-Substituted Malonates to Aromatic Nitroalkenes
作者:Paul J. Nichols、John A. DeMattei、Bradley R. Barnett、Nicole A. LeFur、Tsung-Hsun Chuang、Anthony D. Piscopio、Kevin Koch
DOI:10.1021/ol060398p
日期:2006.3.1
[reaction: see text] The enantioselective conjugateaddition of alpha-substituted malonates to aromatic nitroalkenes generates a stereocenter at the carbon bearing the aromatic group and an adjacent prochiral center from the alpha-substituted malonate. Nitro reduction followed by diastereoselective cyclization provides pyrrolidinones with two contiguous stereocenters, one of which is quaternary. This
4-Trifluoromethanesulfonamidyl prolinol tert-butyldiphenylsilyl ether as a highly efficient bifunctional organocatalyst for Michael addition of ketones and aldehydes to nitroolefins
作者:Chao Wang、Chun Yu、Changlu Liu、Yungui Peng
DOI:10.1016/j.tetlet.2009.02.211
日期:2009.5
4-Trifluoromethanesulfonamidyl prolinol tert-butyldiphenylsilyl ether bifunctionalorganocatalyst 3a is a highly efficient catalyst for the asymmetric Michaeladdition reactions of ketones and aldehydes to nitrostyrenes, leading to syn-selective adducts with excellent yields (>99%), high diastereoselectivities (up to 99:1 dr) and excellent enantioselectivities (up to 99% ee). Control experiments suggested that the