Fluoride-Catalyzed Cross-Coupling of Silylamides to CF3-Acrylates: Access to Highly Functionalized Trifluoromethylated and Quaternary Fluorinated Molecular Architectures

A direct and simple catalytic coupling of nonfluorinated and fluorinated silylbutenamides with β-CF3 α,β-unsaturated esters mediated by fluoride ion was carried out. The transformation proceeded with excellent yields to afford new, highly functionalized trifluoromethylated and quaternary fluorinated products.

SCpRh(III)-Catalyzed Asymmetric C-H Trifluoromethylalkylation of N-Methoxybenzamides with β-Trifluoromethyl-α,β-Unsaturated Ketones

Asymmetric C-H trifluoromethylalkylation represents a novel and straightforward synthetic method for the construction of chiral CF3-containing compounds. However, the reported examples remain limited, given the challenges of reactivity and enantioselective control. Herein, we report a SCpRh(III)-catalyzed asymmetric aryl and alkenyl C-H trifluoromethylalkylation reaction with β-trifluoromethyl-α,β-unsaturated ketones. The chiral CF3-bearing adducts were obtained in moderate to good yields with high enantioselectivity (up to 81% yield and 96% ee). The reaction features mild conditions and broad substrate scope. The chiral CF3-bearing products could undergo diverse functional group transformations.

Diverse Synthetic Transformations Using 4-Bromo-3,3,4,4-tetrafluorobut-1-ene and Its Applications in the Preparation of CF2 CF2 -Containing Sugars, Liquid Crystals, and Light-Emitting Materials

Organic molecules with fluoroalkylene scaffolds, especially a tetrafluoroethylene (CF2 CF2 ) moiety, in their molecular structures exhibit unique biological activities, or can be applied to functional materials such as liquid crystals and light-emitting materials. Although several methods for the syntheses of CF2 CF2 -containing organic molecules have been reported to date, they have been limited to methods using explosives and fluorinating agents. Therefore, there is an urgent need to develop simple and efficient approaches to synthesize CF2 CF2 -containing organic molecules from readily available fluorinated substrates using carbon-carbon bond formation reactions. This personal account summarizes the simple and efficient transformation of functional groups at both ends of 4-bromo-3,3,4,4-tetrafluorobut-1-ene and discusses its synthetic applications to biologically active fluorinated sugars and functional materials, such as liquid crystals and light-emitting molecules.

Visible-Light-Promoted Synthesis of Fluoroalkylated Oximes

A method has been developed for the synthesis of fluoroalkylated oximes, potential fluoroalkyl building-blocks for the synthesis of various organofluorine compounds, from easily available amino substrates and fluoroalkylated alkenes. tBuONO was utilized both as a diazotizing agent and as a NO radical source for the oxime synthesis in the process, and the use of a photocatalyst under visible-light irradiation increased the efficiency of the reaction. Various fluoroalkylated oximes were prepared by a tandem process of aryl radical addition to fluoroalkylated alkene and consecutive oxime generation process, albeit in moderate yields. This differentiated approach, transferring an aromatic system into an electron-deficient fluoroalkylated alkene, expands the scope of substrates where electron-poor aromatic systems could be utilized.

Design, synthesis and evaluation of new fluorinated liquid crystals bearing a CF2CF2 fragment with negative dielectric anisotropy

We designed unique negative dielectric molecules, which were tricyclic compounds with a 5,5,6,6-tetrafluorocyclohexa-1,3-diene moiety in the mesogen, and then for the first time developed an effective synthetic protocol from commercially available 4-bromo-3,3,4,4-tetrafluorobut-1-ene. We also evaluated their physical properties for new mesogenic compounds, such as birefringence, dielectric anisotropy and shear viscosity, which are important characteristics for flat LC display device applications. The molecules clearly showed not only a large negative dielectric anisotropy and birefringence but also high viscosity.

Asymmetric [4+2] annulations to construct norcamphor scaffolds with 2-cyclopentenone via double amine–thiol catalysis

A double catalytic system combining chiral amine and 2-mercaptobenzoic acid is applied for α′,β-regioselective [4+2] annulations of 2-cyclopentenone with diverse activated alkenes.

Copper-Catalyzed Asymmetric Borylation: Construction of a Stereogenic Carbon Center Bearing Both CF3 and Organoboron Functional Groups

Copper-catalyzed borylation of β-trifluoromethyl-α,β-unsaturated ketones was efficiently achieved by means of bis(pinacolato)diboron (B₂pin₂), affording the enantioenriched products in good yields with high enantioselectivities. CuI and (R,S)-Josiphos consist of the most efficient catalyst system under mild conditions. In the absence of the chiral ligand, the reactions could be performed more efficiently to form β-ketone derivatives which were directly borylated and indirectly trifluoromethylated at the β-carbon atom of the α,β-unsaturated ketone substrates. The present protocol provides a promising method to access a stereogenic carbon center bearing both CF₃ and organoboron functional groups.

Copper-catalysed enantioselective Michael addition of malonic esters to β-trifluoromethyl-α,β-unsaturated imines

A diastereo- and enantioselective Michael addition of methyl malonate to β-trifluoromethyl unsaturated imines is presented.

Construction of Furan Derivatives with a Trifluoromethyl Stereogenic Center: Enantioselective Friedel-Crafts Alkylations via Formal Trienamine Catalysis

An asymmetric Friedel-Crafts alkylation reaction of 2-furfuryl ketones with β-trifluoromethyl enones has been developed via formal trienamine catalysis of a bifunctional primary amine-thiourea substance derived from L-tert-leucine, delivering the furan derivatives incorporating a stereogenic trifluoromethyl (CF₃) group in good to high yields with excellent enantioselectivity.

Simple access to β-trifluoromethyl-substituted ketones via copper-catalyzed ring-opening trifluoromethylation of substituted cyclopropanols

Tertiary cyclopropanols react rapidly with Togni reagent in methanol at room temperature in the presence of catalytic amounts (3 mol%) of CuCl affording β-trifluoromethyl ketones in 65-73% isolated yields. Ring opening in 1,2-dialkylsubstituted cyclopropanols gives a mixture of isomeric β-trifluoromethyl ketones in about 50% combined yield.

Rhodium(iii)-catalyzed sp2 C–H bond addition to CF3-substituted unsaturated ketones

Rhodium(iii)-catalyzed conjugate addition of sp² C–H bonds to β-trifluoromethyl-α,β-unsaturated ketones was efficiently achieved.

Copper-catalyzed enantioselective conjugate addition of grignard reagents to methyl 4,4,4-trifluorocrotonate: synthesis of enantioenriched trifluoromethylated compounds

Copper-catalyzed enantioselective 1,4-conjugate addition of methyl 4,4,4-trifluorocrotonate with aliphatic Grignard reagents to access an asymmetric tertiary carbon center attached with a trifluoromethyl group was achieved under mild reaction conditions. The desired products could be obtained in reasonable yields and good enantioselectivities.

Catalytic asymmetric conjugate addition of terminal alkynes to β-trifluoromethyl α,β-enones

The first enantioselective conjugate alkynylation of β-trifluoromethyl α,β-enones using terminal alkynes and a taniaphos–Cu(i) complex as catalyst is described.