A visible-light-induced decarboxylative trifluoromethylation of alpha,beta-unsaturatedcarboxylicacids, which uses the Togni reagent as the CF3 source is disclosed. The corresponding trifluoromethylated alkenes were obtained in moderate to high yields with excellent functional group tolerance at ambient temperature. Preliminary mechanistic analyses suggest a radical-type mechanism.
(<i>Z</i>)- or (<i>E</i>)-Selective Hydrogenation of Potassium (3,3,3-Trifluoroprop-1-yn-1-yl)trifluoroborate: Route to Either Isomer of β-Trifluoromethylstyrenes
vinylborate in >98% purity is described. The initially formed (Z)-isomer of the alkene is transformed to the (E)-isomer with time, irrespective of the catalyst used; coupling with bromo- and iodoarenes provides a variety of (Z)- or (E)-β-trifluoromethylstyrenes. Also, a safe synthesis of the alkynyltrifluoroborate from HFC-245fa and BF3·OEt2 has been described.