Kinetic study of trifluoromethylation with s-(trifluoromethyl) dibenzothiophenium salts

An ab initio and DFT study of trifluoromethylation using Umemoto's reagent

Theoretical calculations revealed that trifluoromethylation using Umemoto's reagent would occur through the ionic backside mechanism.

An Energetic Guide for Estimating Trifluoromethyl Cation Donor Abilities of Electrophilic Trifluoromethylating Reagents: Computations of X-CF3 Bond Heterolytic Dissociation Enthalpies

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.

Trifluoromethylation of alkenes with concomitant introduction of additional functional groups

The trifluoromethyl group is found in many synthetic bioactive compounds, and the difunctionalization of a C=C bond, as a powerful strategy for the construction of compounds with various functional groups, has been intensively investigated. Therefore, the difunctionalizing trifluoromethylation of alkenes has attracted growing interest because of the potential of the products as building blocks for bioactive molecules. In this review, we focus on recent advances in the trifluoromethylation of alkenes with concomitant introduction of additional functional groups.

Is universal, simple melting point prediction possible?

An investigation of the melting points of 520 organic 1:1 salts is presented with the aim of developing a universal, simple, physically well-founded prediction scheme. The general reliability and reproducibility of the recorded experimental data are discussed with respect to purity, phase behavior, disorder and thermal history of a given substance. Additionally, mistakes, systematic errors, or lack of conventions can lead to considerable differences in the experimental measurements. A rough error bar for the reproducibility of the melting points of organic salts of ±5 to ±15 °C can be assigned. With this restraint, we developed two simple, semiempirical, five- and nine-parameter schemes with easy-to-calculate quantities. With these, we could predict the melting temperature of a given organic salt in the temperature range of -25 to +300 °C with an average error of 33.5 °C and a relative error of 9.3%. All calculated quantities are assessed with the help of conventional DFT, COSMO and COSMO-RS calculations, and are currently implemented into the IL-Prop module of the upcoming version of COSMOtherm. These prediction schemes are suitable for high-throughput computational screening of substances in the context of "computer-aided synthesis". Therefore, they are valuable tools to find a compound with a suitable melting point before its first synthesis.