Enantioselective organocatalytic oxa-Michael addition of oximes to β-CF<sub>3</sub>-β-disubstituted nitroalkenes: efficient synthesis of β-amino-α-trifluoromethyl alcohols
We report the first asymmetric sulfa-Michael addition (SMA) reactions using chiral N-heterocycliccarbene (NHC) as a non-covalent organocatalyst. We demonstrate that a triazolium salt derived NHC functions as an excellent...
Highly Enantioselective Aza‐Michael Reaction between Alkyl Amines and β‐Trifluoromethyl β‐Aryl Nitroolefins
作者:Leming Wang、Jiean Chen、Yong Huang
DOI:10.1002/anie.201508371
日期:2015.12.14
aza‐Michael addition reaction is a vital transformation for the synthesis of functionalized chiral amines. Despite intensive research, enantioselective aza‐Michael reactions with alkyl amines as the nitrogen donor have not been successful. We report the use of chiral N‐heterocyclic carbenes (NHCs) as noncovalent organocatalysts to promote a highly selective aza‐Michael reaction between primary alkyl
Highly enantioselective construction of CF3-bearing all-carbon quaternary stereocenters: Chiral spiro-fused bisoxazoline ligands with 1,1′-binaphthyl sidearm for asymmetric Michael-type Friedel-Crafts reaction
作者:Robert Li-Yuan Bao、Lei Shi、Kang Fu
DOI:10.1016/j.cclet.2021.10.062
日期:2022.5
A novel class of chiral spiro-fused bisoxazolineligands possessing a deep chiral pocket was prepared. The developed ligands have been employed in the nickel-catalyzed highly enantioselective Michael-type Friedel-Crafts reaction, affording the products bearing a trifluoromethylated all-carbon quaternary stereocenter with moderate to excellent yields (up to 99%) and good to excellent enantioselectivies
制备了一类具有深手性口袋的新型手性螺稠合双恶唑啉配体。开发的配体已用于镍催化的高对映选择性迈克尔型傅克反应,提供具有中等至优异产率(高达 99%)和良好至优异对映选择性(高达> 99.9% ee )。此外,提出的手性口袋模型表明,吲哚从β - CF 3 - β-二取代硝基烯烃的Re-面进攻是有利的。
The squaramide-catalyzed asymmetric Michael/cyclization tandem reaction for the synthesis of chiral trifluoromethylated hydroxyimino tetrahydrobenzofuranones
An enantioselective synthesis of trifluoromethylated hydroxyimino tetrahydrobenzofuranones has been developed. 1,3-Dicarbonyl carbocyclic compounds react with β-CF3-β-disubstituted nitroalkenes in the presence of a chiral squaramide catalyst, providing efficient access to diverse hydroxyimino tetrahydrobenzofuranones featuring a trifluoromethyl group at the C3-position of an all-carbon quaternary stereocenter