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The recombination of CF3 and CHF2 radicals in a room-temperature bath gas was used to prepare vibrationally excited CF3CHF2* molecules with 101 kcal mol-1 of vibrational energy. The subsequent 1,2-H atom transfer and 1,1-HF and 1,2-HF elimination reactions were observed as a function of bath gas pressure by following the CHF3, CF3(F)C: and C2F4 product concentrations by gas chromatography using a mass spectrometer as the detector. The singlet CF3(F)C: concentration was measured by trapping the carbene with trans-2-butene. The experimental rate constants are 3.6 × 104, 4.7 × 104, and 1.1 × 104 s-1 for the 1,2-H atom transfer and 1,1-HF and 1,2-HF elimination reactions, respectively. These experimental rate constants were matched to statistical RRKM calculated rate constants to assign threshold energies (E0) of 88 ± 2, 88 ± 2, and 87 ± 2 kcal mol-1 to the three reactions. Pentafluoroethane is the only fluoroethane that has a competitive H atom transfer decomposition reaction, and it is the only example with 1,1-HF elimination being more important than 1,2-HF elimination. The trend of increasing threshold energies for both 1,1-HF and 1,2-HF processes with the number of F atoms in the fluoroethane molecule is summarized and investigated with electronic-structure calculations. Examination of the intrinsic reaction coordinate associated with the 1,1-HF elimination reaction found an adduct between CF3(F)C: and HF in the exit channel with a dissociation energy of ~5 kcal mol-1. Hydrogen-bonded complexes between HF and the H atom migration transition state of CH3(F)C: and the F atom migration transition state of CF3(F)C: also were found by the calculations. The role that these carbene-HF complexes could play in 1,1-HF elimination reactions is discussed. [ABSTRACT FROM AUTHOR]

A primary amine-catalyzed asymmetric formal aza-Diels-Alder reaction of trifluoromethyl hemiaminals with enones was developed via a chiral gem-diamine intermediate. This novel protocol allowed facile access to structurally diverse trifluoromethyl-substituted piperidine scaffolds with high stereoselectivity. The utility of this method was further demonstrated through a concise approach to biologically active 4-hydroxypiperidine. More importantly, a stepwise mechanism involving an asymmetric induction process was proposed to rationalize the positive correlation between the chirality of the gem-diamine intermediate and the formal aza-Diels-Alder product. [ABSTRACT FROM AUTHOR]

This work established an energetic guide for estimating the trifluoromethyl cation-donating abilities (TC+DA) of electrophilic trifluoromethylating reagents through computing X-CF3 bond (X = O, S, Se, Te, and I) heterolytic dissociation enthalpies. TC+DA values for a wide range of popular reagents were derived on the basis of density functional calculations (M06-2X). A good correspondence has been identified between the computed TC+DA values and the experimentally observed relative trifluoromethylating capabilities of the reagents. Substituent effects hold good linear free energy relationships on the TC+DAs of the most widely used reagents including Umemoto reagent, Yagupolskii-Umemoto reagent, and Togni reagents, which allow their trifluoromethylating capabilities to be rationally tuned by substituents and thus extend their synthetic utility. All the information disclosed in this work would contribute to future rational exploration of the electrophilic trifluoromethylation chemistry. [ABSTRACT FROM AUTHOR]

A self-catalyzed aza-Henry addition of ethyl nitroacetate on N-alkyl trifluoromethyl aldimines was reported to synthesize β-amino α-nitro trifluoromethyl esters, precursors of α,β-diamino acid derivatives. In the presence of a resident chiral center on the imine nitrogen, the use of a suitable Lewis acid leads to a good stereofacial control, always resulting from a nucleophilic unlike attack. By starting from optically pure N-protected trifluoromethyl aldimines or directly from N-α-amino ester trifluoromethyl aldimines, small ψ[CH(CF3)NH]-peptidomimetic backbones can be achieved in which a new primary amine function represents a possible center for synthetic extension. Finally, a very interesting, and never observed before, palladium-catalyzed syn β-elimination occurred, leading to the selective nitro group reduction reaction on the syn-α-amino ester functionalized aza-Henry adducts and obtaining more stable optically pure trifluoromethyl conjugated imines. [ABSTRACT FROM AUTHOR]

Recently, Smith and co-workers reported an interesting work that provides a facile approach to access substituted trifluoromethyl dihydropyranones with two contiguous stereocenters by utilizing the a,β-unsaturated trifluoromethyl ketones as a substrate for NHC-catalyzed [4 + 2] cycloadditions. The most significant point of this reaction lies in the capability of introducing substituents to the C(5) position of the dihydropyranones. In the present study, we performed detailed DFT investigations toward the catalytic mechanism of this reaction, and determined origins of the diastereo- and enatioselectivities through analyses on distortion energies of two key stationary species and on components of Gibbs free energy barriers of elementary steps in which the stereocenters are generated. The theoretically predicted configuration of the main product was well-consistent with the experimental results, and the excellent correlation between the relative free energy barriers (ΔΔG2980) with the relative enthalpy barriers (ΔΔH2980) indicates that the stereoselectivity should originate from differences of enthalpy barriers rather than distinctions of the entropy item (-TΔS2980) changes. The systematic study of the substituent effect affords conclusive evidence for the catalytic mechanism we proposed but failed to give any clue to how the various electronic properties of substituents act on the experimental yields. [ABSTRACT FROM AUTHOR]

Recently, Smith and co-workers reported an interesting work that provides a facile approach to access substituted trifluoromethyl dihydropyranones with two contiguous stereocenters by utilizing the α,β-unsaturated trifluoromethyl ketones as a substrate for NHC-catalyzed [4 + 2] cycloadditions. The most significant point of this reaction lies in the capability of introducing substituents to the C(5) position of the dihydropyranones. In the present study, we performed detailed DFT investigations toward the catalytic mechanism of this reaction, and determined origins of the diastereo- and enatioselectivities through analyses on distortion energies of two key stationary species and on components of Gibbs free energy barriers of elementary steps in which the stereocenters are generated. The theoretically predicted configuration of the main product was well-consistent with the experimental results, and the excellent correlation between the relative free energy barriers (ΔΔG2980) with the relative enthalpy barriers (ΔΔH2980) indicates that the stereoselectivity should originate from differences of enthalpy barriers rather than distinctions of the entropy item (-TΔS2980) changes. The systematic study of the substituent effect affords conclusive evidence for the catalytic mechanism we proposed but failed to give any clue to how the various electronic properties of substituents act on the experimental yields. [ABSTRACT FROM AUTHOR]

The photoinduced perfluoroalkylation of anthracene has been shown to provide 9,9′,10,10′-tetrahydro-10,10′-diperfluoroalkyl-9,9′-bianthracenes in over 70% yields, each perfluoroalkyl iodide producing three diastereomers. The structures of all three diastereomers (cis, cis, cis, trans, and trans, trans isomers) have been elucidated by both NMR and X-ray crystallographic analyses. Most notably, an X-ray crystallographic analysis has revealed that the trans, trans diastereomer having the two trifluoromethyl groups in 10,10′-positions adopts a 74° twisted relationship of the two dihydroanthracene rings. Furthermore, each of the two trans, trans isomers 2a,b has been shown to exist as a mixture of new types of atropisomers and the energy barrier for the interconversion of the two atropisomers has been estimated to be 12 kcal/mol by variable-temperature NMR analysis. [ABSTRACT FROM AUTHOR]

Cp*Rh(III) complexes have been applied as efficient catalysts for the C-H activation and trifluoromethylthiolation of indoles functionalized with a heterocycle. With N-trifluoromethylthiosaccharin being an electrophilic SCF3 reagent, this C-S coupling occurred selectively at the 2-position with good functional group tolerance. [ABSTRACT FROM AUTHOR]

A method for the synthesis of fluorinated β'-amino β-dicarbonyl compounds using a Zr-catalyzed Mannich-type reaction has been developed, starting from N-protected trifluoromethyl aldimines and cyclic or acyclic β-keto esters bearing different ester residues. The in situ generated metallic complex reacted with optically pure trifluoromethyl aldimine derived from (R)-α-methylbenzylamine, giving a highly diastereoselective asymmetric Mannich-type addition with formation of a chiral quaternary center. The absolute configuration at the new chiral centers was assigned through two-dimensional nuclear Overhauser effect spectroscopic analysis coupled with computational studies. [ABSTRACT FROM AUTHOR]

Measured DMSO pKa values for a series of rigid tricyclic adamantane-like triols containing 0-3 trifluoromethyl groups (i.e., 3(0)-3(3)) are reported. The three compounds with CF3 substituents are similar or more acidic than acetic acid (pKa = 13.5 (3(1)), 9.5 (3(2)), 7.3 (3(3)) vs 12.6 (HOAc)), and the resulting hydrogen bond network enables a remote γ-trifluoromethyl group to enhance the acidity as well as one located at the α-position. Catalytic abilities of 3(0)-3(3) were also examined. In a nonpolar environment a rate enhancement of up to 100-fold over flexible acyclic analogs was observed presumably due to an entropic advantage of the locked-in structure. Gas-phase acidities are found to correlate with the catalytic activity better than DMSO pKa values and appear to be a better measure of acidities in low dielectric constant media. These trends are reduced or reversed in polar solvents highlighting the importance of the reaction environment. [ABSTRACT FROM AUTHOR]

Trifluoromethanesulfonic acid (HOTf) promoted cross-coupling of ortho-[2-(4-methoxylphenyl)-alkynyl]acetophenones with ortho-alkynylbenzaldehydes affording chrysene derivatives has been developed. The present cascade reaction provides a facile one-pot synthesis of multisubstituted chrysenes as well as naked chrysene under mild conditions. The mechanism experimental results demonstrate isochromenylium is a key intermediate for this transformation. [ABSTRACT FROM AUTHOR]

A mild and practical protocol for manganese-catalyzed aerobic oxytrifluoromethylation of olefinic bonds of styrene derivatives using CF3SO2Na (Langlois' reagent) as the CF3 source is described. A distinguishing feature of this method is the generation of trifluoromethyl radicals from CF3SO2Na using the simple manganese salt/O2 system. The reaction proceeds under ambient conditions, free of added peroxide initiators, and provides moderate to good selectivities for alcohol versus ketone product. [ABSTRACT FROM AUTHOR]

This paper presentsthe first microwave spectroscopic investigation on hexafluoroisopropanol(HFIP). A pulsed nozzle Fourier transform microwave spectrometer hasbeen used to determine the rotational constants for HFIP as A= 2105.12166(18) MHz, B= 1053.99503(12)MHz, and C= 932.33959(13) MHz. In addition, fiveisotopologues of HFIP have been observed experimentally to determinethe accurate structure of HFIP. The observed spectrum could be assignedto the most stable conformer of HFIP, called antiperiplanar. Availablespectroscopic information and ab initio calculations on five prototypemolecules helped in exploring the torsional behavior of moleculeshaving a CF3–C–CF3group. Two-dimensionalpotential energy surfaces have been analyzed for all molecules, whichexplained the presence/absence of doubling in the rotational transitions.With the help of natural bond orbital (NBO) analysis, reasons forthe conformational preference of HFIP have been explained. [ABSTRACT FROM AUTHOR]

The enantioselective N-heterocyclic carbene-catalyzed [4 + 2] cyclocondensation of a-chloroaldehydes and trifluoromethyl N-Boc azadienes was developed, giving the corresponding 3,4-disubstituted-6-trifluoromethyldihydropyridin-2(1H)-ones in good yields with exclusive cis-selectivities and excellent enantioselectivities. [ABSTRACT FROM AUTHOR]

Herein is reported a study of asymmetric decarboxylative Mannich addition reactions between (Ss)-N-t-butylsulfinyl-3,3,3-trifluoroacetaldimine and Schiff bases derived from various aldehydes and lithium 2,2-diphenylglycinate. These reactions proceed with excellent diastereoselectivities and good chemical yields, providing a practical method for preparation of trifluoromethyl-containing vicinal diamines. The procedures can be conducted under convenient conditions, rendering this approach of high synthetic value. [ABSTRACT FROM AUTHOR]

The synthesis of a series of α-trifluoromethylcyclohexanols and analogous trimethylsilyl ethers by addition of the Ruppert-Prakash reagent to substituted cyclohexanones is presented. A method for the assignment of configuration of such compounds, of related α-trifluoromethylcyclohexylamines and of quaternary trifluoromethyl-substituted carbons is described based on the determination of the ³JCH coupling constant between the fluorine-decoupled 13CF3 resonance and the vicinal hydrogens. This method is dubbed fluorine-decoupled carbon spectroscopy and abbreviated FDCS. The method is also applied to the configurational assignment of substances bearing mono-, di-, and perfluoroalkyl rather than trifluoromethyl groups. The configuration of all substances was verified by either 19F-¹H heteronuclear Overhauser spectroscopy (HOESY) or X-ray crystallography. The relative merits of FDCS and HOESY are compared and contrasted. ²JCH, ³JCH, and 4JCH coupling constants to 19F decoupled CF3 groups in alkenes and arenes have also been determined and should prove to be useful in the structural assignment of trifluoromethylated alkenes and arenes. [ABSTRACT FROM AUTHOR]

A practical and efficient method for preparation of highly enantiomerically enriched 3-cyano-3-aminooxindoles and 3-trifluoromethyl-3-aminooxindoles with up to 99% optical purity by a Lewis acid promoted diastereoselective Strecker reaction and trifluoromethylation of isatin-derived N-tert-butanesulfinyl ketimines has been developed. This protocol allows direct use of N-free isatin substrates under mild conditions. [ABSTRACT FROM AUTHOR]

The application of ab initio and DFT computational methods at six different levels of theory (MP2/cc-pVDZ, MP2/aug-cc-pVTZ, B3LYP/cc-pVDZ, B3LYP/aug-cc-pVTZ, M06/cc-pVDZ, and M06/aug-cc-pVTZ) to meta- and para-substituted fluoro- and trifluoromethylbenzene derivatives and to 1-fluoro- and 1-trifluoromethyl-2-substituted trans-ethenes allowed the study of changes in the electronic and geometric properties of F- and CF3-substituted systems under the impact of other substituents (BeH, BF2, BH2, Br, CFO, CHO, Cl, CN, F, Li, NH2, NMe2, NO, NO2, OH, H, CF3, and CH3). Various parameters of these systems have been investigated, including homodesmotic reactions in terms of the substituent effect stabilization energy (SESE), the π and σ electron donor-acceptor indexes (pEDA and sEDA, respectively), the charge on the substituent active region (cSAR, known earlier as qSAR), and bond lengths, which have been regressed against Hammett constants, resulting mostly in an accurate correspondence except in the case of p-fluorobenzene derivatives. Moreover, changes in the characteristics of the ability of the substituent to attract or donate electrons under the impact of the kind of moiety to which the substituent is attached have been considered as the indirect substituent effect and investigated by means of the cSAR model. Regressions of cSAR(X) versus cSAR(Y) for any systems X and Y allow final results to be obtained on the same scale of magnitude. [ABSTRACT FROM AUTHOR]

The first example of a copper(I)-catalyzed intramolecular aminotrifluoromethylation of unactivated alkenes using (TMS)CF3 (trimethyl(trifluoromethyl)silane) as the CF3 source is described. A broad range of electronically and structurally varied substrates undergo convenient and step-economical transformations for the concurrent construction of a five- or six-membered ring and a C-CF3 bond toward different types of trifluoromethyl azaheterocycles. The methodology not only circumvents use of expensive electrophilic CF3 reagents or the photoredox strategy but also expands the scope to substrates that are difficult to access by the existing methods. Mechanistic studies are conducted, and a plausible mechanism is proposed. [ABSTRACT FROM AUTHOR]

A sequential oxidative radical alkoxycarbonylation and aromatization of 2-isocyanobiphenyl with carbazates was developed to furnish phenanthridine-6-carboxylates. Various functional groups such as methoxy, chloro, fluoro, trifluoromethoxy, and trifluoromethyl groups were tolerated well under the reaction conditions. The sequential radical addition-cyclization strategy represents a practical route to access phenanthridine-6-carboxylates. [ABSTRACT FROM AUTHOR]

A method has been developed for the synthesis of α-trifluoromethyl ketones via the Cu-catalyzed trifluoromethylation of silyl enol ethers with an electrophilic trifluoromethylating agent, which produces a trifluoromethyl radical. [ABSTRACT FROM AUTHOR]

We present a survey and theoreticalinterpretation of the experimentalresults on trifluoromethylation of fullerenes. A thermodynamic modelhas been developed to describe the C60/70(CF3)ncondensed phase mixtures capable offree exchange of addends and, consequently, of isomerization and changingthe degrees of addition. It was found that the purely thermodynamicmodel affords at least satisfactory prediction of composition of productseven for apparently nonequilibrium syntheses. Special cases can beidentified by means of detailed kinetic modeling based on the BEPapproach, which includes stepwise energetic analysis of the possibletrifluoromethylation sequences. This analysis reveals two types ofreactions with remarkable difference in rates: direct trifluoromethylationand rearrangements of the CF3groups. Whenever a particulargroup of compounds is interrelated through direct addition/abstractionof CF3groups, it is more or less safe to assume that thesaid group is in equilibrium describable by the thermodynamic model.In the same time, the slower migration of addends is controlled kinetically,and interference of the sublimation processes frequently preventsits equilibration. Among the most illustrative examples of hinderedformation via rearrangements in absence of sufficiently favorabledirect trifluoromethylation pathways are certain isomers of the C3v–C60(CF3)18, C70(CF3)18, and C70(CF3)20compounds. [ABSTRACT FROM AUTHOR]

A palladium-catalyzed tandem Suzuki/C--H arylation reaction of N-aryltrifluoroacetimidoyl chlorides with arylboronic acids has been developed. A variety of 6-(trifluoromethyl)phenanthridines were prepared in moderate to excellent yields from N-(2-bromophenyl)trifluoroacetimidoyl chlorides which can be conveniently prepared from 2-bromoaniline derivatives. [ABSTRACT FROM AUTHOR]

Incorporation of a trifluoromethyl group into the structure of 4-(alkoxycarbonyl)vinyldiazocarbonyl compounds greatly decreases the tendency of the carbenoid intermediates formed during Rh(II)-catalyzed reactions to undergo intermolecular processes. Instead, they are prone to experience intramolecular [1,5]- and [1,3]-electrocyclizations to produce reactive cyclopropenes and furans, and these are capable of further transformations. [ABSTRACT FROM AUTHOR]

By utilizing Rh catalysts ligated by the P-chirogenic ligands QuinoxP* and DuanPhos, 3,3,3-trifluoroprop-1-en-2-yl acetate could be hydroformylated and subsequently oxidized to yield enantiomerically pure 2-trifluoromethyllactic acid. [ABSTRACT FROM AUTHOR]

A feasible nucleophilic trifluoromethylating protocol has been developed using trifluoroacetaldehyde hydrate as an atom-economical trifluoromethyl source. The reaction was found to be applicable to the nucleophilic trifluoromethylation of a broad spectrum of carbonyl compounds with satisfactory yields in general. DFT calculations have been performed to provide mechanistic insight into the present and related reactions employing 2,2,2-trifluoro-1-methoxyethanol and hexafluoroacetone hydrate. [ABSTRACT FROM AUTHOR]

Herein, we present a comparative study of the thermophysicalpropertiesof two homologous ionic liquids, namely, trimethyl-sulfonium bis[(trifluoromethyl)sulfonyl]imide,[S111][TFSI], and trimethyl-ammonium bis[(trifluoromethyl)sulfonyl]imide,[HN111][TFSI], and their mixtures with propylene carbonate,acetonitrile, or gamma butyrolactone as a function of temperatureand composition. The influence of solvent addition on the viscosity,conductivity, and thermal properties of IL solutions was studied asa function of the solvent mole fraction from the maximum solubilityof IL, xs, in each solvent to the puresolvent. In this case, xsis the compositioncorresponding to the maximum salt solubility in each liquid solventat a given temperature from 258.15 to 353.15 K. The effect of temperatureon the transport properties of each binary mixture was then investigatedby fitting the experimental data using Arrhenius’ law and theVogel–Tamman–Fulcher (VTF) equation. The experimentaldata shows that the residual conductivity at low temperature, e.g.,263.15 K, of each binary mixture is exceptionally high. For example,conductivity values up to 35 and 42 mS·cm–1were observed in the case of the [S111][TFSI] + ACN and[HN111][TFSI] + ACN binary mixtures, respectively. Subsequently,a theoretical approach based on the conductivity and on the viscosityof electrolytes was formulated by treating the migration of ions asa dynamical process governed by ion–ion and solvent–ioninteractions. Within this model, viscosity data sets were first analyzedusing the Jones–Dole equation. Using this theoretical approach,excellent agreement was obtained between the experimental and calculatedconductivities for the binary mixtures investigated at 298.15 K asa function of the composition up to the maximum solubility of theIL. Finally, the thermal characterization of the IL solutions, usingDSC measurements, showed a number of features corresponding to differentsolid–solid phase transitions, TS–S, with extremely low melting entropies, indicating a strong organizationalstructure by easy rotation of methyl group. These ILs can be classifiedas plastic crystal materials and are promising as ambient-temperaturesolid electrolytes. [ABSTRACT FROM AUTHOR]

Unambiguous evidence for the engagement of CF3groupin N–H···F–C hydrogen bond in a low polaritysolvent, the first observation of its kind, is reported. The presenceof such weak molecular interactions in the solution state is convincinglyestablished by one and two-dimensional 1H, 19F, and natural abundant 15N NMR spectroscopic studies.The strong and direct evidence is derived by the observation of through-spacecouplings, such as, 1hJFH, 1hJFN, and 2hJFF, where the spin polarization is transmittedthrough hydrogen bond. In an interesting example of a molecule containingtwo CF3groups getting simultaneously involved in hydrogenbond, where hydrogen bond mediated couplings are not reflected inthe NMR spectrum, 19F–19F NOESY experimentyielded confirmatory evidence. Significant deviations in the strengthsof 1JNH, variable temperature,and the solvent induced perturbations yielded additional support.The NMR results are corroborated by both DFT calculations and MD simulations,where the quantitative information on different ways of involvementof fluorine in two and three centered hydrogen bonds, their percentageof occurrences, and geometries have been obtained. The hydrogen bondinteraction energies have also been calculated. [ABSTRACT FROM AUTHOR]

A simple, mild method for the oxidation of α-trifluoromethyl alcohols to trifluoromethyl ketones (TFMKs) using the oxoammonium salt 4-acetylamino-2,2,6,6-tetrame-thylpiperidine-1-oxoammonium tetrafluoroborate (1) is described. Under basic conditions, oxidation proceeds rapidly and affords good to excellent yields of TFMKs, without concomitant formation of the hydrate. The byproduct of the oxidation, 4-acetylamino-2,2,6,6-tetramethyl-1-piperidinyloxy (1c), is easily recovered and can be conveniently reoxidized to regenerate the oxoammonium salt. [ABSTRACT FROM AUTHOR]

Rotational spectra for hexafluoroisobutene, and its 13C isotopologues, have been recorded between 8 and 16 GHzusing achirped pulse, Fourier transform microwave spectrometer. Notably,all spectra observed are doubled with separations between the doubletsbeing between 1 and 60 MHz. We propose that the bis-trifluoromethylgroups of the target molecule are staggered in the equilibrium configuration,and that a novel, out-of-phase rotation through a F-CCC-F planar configurationwith low barrier (<100 cm–1), leads to the observeddoubled rotational spectra. [ABSTRACT FROM AUTHOR]

Gaseous solubilities of carbon dioxide (1), hydrogensulfide (2),and their binary mixture (x2≈0.2, 0.5, 0.8) have been measured in the ionic liquid 1-octyl-3-methylimidazoliumbis(trifluoromethyl)sulfonylimide ([C8mim][Tf2N]) at temperatures ranging from (303.15 to 353.15) K and at pressuresunder 2 MPa. The observed PTxsolubility data wereused to obtain Henry's law constants and correlated by three models:(1) the simple Krichevsky–Kasarnovsky (KK) equation, (2) amodel comprised of the extended Henry's law and the Pitzer's virialexpansion for the excess Gibbs free energy, and (3) the generic Redlich–Kwong(RK) cubic equation of state proposed for gas–ionic liquidsystems. The correlations from the three models show quite good consistencywith the experimental data for IL/CO2and IL/H2S binary mixtures within experimental uncertainties. For IL/CO2/H2S ternary mixtures, the RK model shows the bestcorrelation with the experimental data. The comparison showed thatthe solubility of H2S is about two times as great as thatof CO2in the ionic liquid studied in this work. It wasfurther found, by comparison of the experimental data of this studywith those of previous reports, that the solubility of H2S in [Cnmim][Tf2N] ILs increasesas the number of carbon atoms in the alkyl substituent of methylimidazoliumcation, n, increases. In addition, quantum chemicalcalculations at DFT/B3LYP level of theory using 6-311(d) and 6-311(2d,2p)basis sets were performed on the isolated systems studied in thiswork to provide explanations from a molecular point of view for theobserved experimental trends. [ABSTRACT FROM AUTHOR]

Ethyl 2-diazo-4,4,4-trifluoro-3-oxobutanoate is a highly versatile intermediate for the synthesis of a wide range of trifluoromethyl heterocycles. With the use of rhodium(II) or copper(II) catalyzed carbene X-H insertion reactions as key steps, a diverse set of trifluoromethyl-oxaioles, -thiazoles, -imidazoles, -1,2,4-triazines, and -pyridines are available from the diazoketoester, either directly in a single step or with just one additional step. [ABSTRACT FROM AUTHOR]

Straightforward practical synthetic approaches to 3,4-bis-and 3,4,5-tris(trifluoromethyl)pyrazoles have been developed. The key step of the both syntheses is a transformation of the carboxylic group in a pyrazole core into the trifluoromethyl group by sulfur tetrafluoride. The elaborated synthetic protocols allow gram-scale preparation of the target products. The obtained compounds are comprehensively characterized by means of crystallographic analysis, determination of pKa values and fluorescence measurements. [ABSTRACT FROM AUTHOR]

A method for trifluoromethylation of alkenes has been developed employing visible light photoredox catalysis withCF3I, Ru(Phen)3Cl2, and DBU. This process works especially well for terminal alkenes to give alkenyl-CF3 products with only E-stereochemistry. The mild reaction conditions enable the trifluoromethylation of a range of alkenes that bear various functional groups. [ABSTRACT FROM AUTHOR]