Highly Enantioselective Construction of Trifluoromethylated All-Carbon Quaternary Stereocenters via Nickel-Catalyzed Friedel–Crafts Alkylation Reaction
A highlyenantioselectiveFriedel-Craftsalkylation reaction of indoles with β-CF(3)-β-disubstituted nitroalkenes was achieved using a Ni(ClO(4))(2)-bisoxazoline complex as a catalyst, which afforded indole-bearing chiral compounds with trifluoromethylated all-carbon quaternary stereocenters in good yields with excellent enantioselectivities (up to 97% ee). The transformation of one of the products
Access to Chiral GABA Analogues Bearing a Trifluoromethylated All-Carbon Quaternary Stereogenic Center through Water-Promoted Organocatalytic Michael Reactions
作者:Jae Hun Sim、Jin Hyun Park、Pintu Maity、Choong Eui Song
DOI:10.1021/acs.orglett.9b02320
日期:2019.9.6
dithiomalonates. Under on-water conditions, the reaction rates were remarkably accelerated as a result of enforced hydrophobic interactions between catalysts and reactants. Takemoto-type thiourea catalysts are very effective for this transformation, affording highly enantioenriched Michael adducts that provide simple access to chiral γ-aminobutyric acid (GABA) analogues with a β-trifluoromethylated quaternary
Catalytic highly enantioselective transfer hydrogenation of β-trifluoromethyl nitroalkenes. An easy and general entry to optically active β-trifluoromethyl amines
An easy, general and highly enantioselective entry to optically active β-trifluoromethyl amines via organocatalytic transfer hydrogenation of β-trifluoromethyl nitroalkenes is presented.
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
Catalytic asymmetric synthesis of enantioenriched β-nitronitrile bearing a C-CF<sub>3</sub>stereogenic center
作者:Ajay Jakhar、Prathibha Kumari、Mohd Nazish、Noor-ul H. Khan、Rukhsana I. Kureshy、Sayed H. R. Abdi、E. Suresh
DOI:10.1039/c6ra00093b
日期:——
all-carbon quaternary stereogenic center have been synthesized via asymmetric cyanation reaction. In situ generated chiral TiIV salen complexes were used as catalysts for asymmetric addition of TMSCN to nitroolefins containing a trifluoromethylated prochiral center in the β-position, to afford the corresponding β-nitronitriles in excellent yield (up to 93%) with good enantioselectivity (up to 99%)
通过不对称氰化反应合成了具有全碳季立体中心的CF 3取代的β-腈。原位生成的手性Ti IV salen络合物用作催化剂,用于将TMSCN不对称加成到在β位上含有三氟甲基化手性中心的硝基烯烃中,从而以良好的对映选择性(良好的产率(高达93%))提供相应的β-腈(高达99%)。这种新开发的催化方案导致有效合成但有用的手性α,α'-二取代的β-氨基酸。