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
Bianthryl-based organocatalysts for the asymmetric Henry reaction of fluoroketones
作者:Jan Otevrel、David Svestka、Pavel Bobal
DOI:10.1039/c9ob00884e
日期:——
catalytic system based on bianthrylbis(thiourea) for the asymmetric Henry reaction of fluoroketones and nitroalkanes that resulted from the screening of a library containing 31 chiral non-racemic organocatalysts. The corresponding adducts were isolated in up to 6 times shorter reaction time in comparison with the previously published organocatalysts. High levels of stereocontrol have been generally observed
Asymmetric Construction of Pyrrolidines Bearing a Trifluoromethylated Quaternary Stereogenic Center via Cu<sup>I</sup>
-Catalyzed 1,3-Dipolar Cycloaddition of Azomethine Ylides with β-CF<sub>3</sub>
-β,β-Disubstituted Nitroalkenes
convenient method has been developed for the synthesis of opticallyactivepyrrolidines bearing a quaternary stereogenic center containing a CF3 group at the C‐3 position of the pyrrolidine ring. The synthesis system, CuI/Si‐FOXAP‐catalyzed exo‐selective 1,3‐dipolar cycloaddition of azomethine ylides with β‐CF3‐β,β‐disubstituted nitroalkenes, provides pyrrolidines with high diastereoselectivities (up to
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。
Enantioselective Organocatalytic Reduction of β-Trifluoromethyl Nitroalkenes: An Efficient Strategy for the Synthesis of Chiral β-Trifluoromethyl Amines
β‐trifluoromethyl‐substituted nitroalkenes, mediated by 3,5‐dicarboxylic ester‐dihydropyridines (Hantzsch ester type), has been successfully developed. A multifunctional thiourea‐based (S)‐valine derivative was found to be the catalyst of choice, promoting the reaction in up to 97 % ee. The methodology has been applied to a wide variety of substrates, leading to the formation of differently substituted precursors