Pd-catalyzed divergent trifluoroethylation and arylation of arylboronic acids by aryl(2,2,2-trifluoroethyl)iodonium triflates.

Highly electrophilic aryl(2,2,2-trifluoroethyl)iodonium triflates have been used for the first time as trifluoroethyl and aryl transfer reagents in Pd-catalyzed functionalization of arylboronic acids. Electron-rich arylboronic acids reacted with aryl(2,2,2-trifluoroethyl)iodonium triflates (2a-b) in CH3CN in the presence of Pd2(dba)3 and K3PO4 at room temperature to provide trifluoroethyl arenes in up to 82% yield, while the reactions of both electron-rich and -poor arylboronic acids with 2a-b in DMF in the presence of Pd[P(t-Bu)3]2 and Cs2CO3 at 40 °C afforded arylation products in up to 99% yield. This tunable protocol allows access to trifluoroethyl arenes or biaryls in good to excellent yields under mild conditions and without the addition of extra ligands.

Organic Photoredox-Catalyzed Decarboxylative Trifluoromethylselenolation of Aliphatic Carboxylic Acids with [Me4N][SeCF3].

Oxidative decarboxylation/trifluoromethylselenolation of primary, secondary, and tertiary aliphatic carboxylic acids with the nucleophilic [Me4N][SeCF3] salt and an organic photocatalyst is described. The reaction proceeds smoothly at room temperature under transition-metal-free conditions and affords the corresponding trifluoromethylselenolated products in good yields. Advantages of the method include good functional group tolerance, without preactivation of the acids, and late-stage functionalization of the complex drug molecules. This protocol represents the first decarboxylative trifluoromethylselenolation of carboxylic acids to trifluoromethyl selenoethers.

TfOH-Promoted Transition-Metal-Free Cascade Trifluoroethylation/Cyclization of Organic Isothiocyanates by Phenyl(2,2,2-trifluoroethyl)iodonium Triflate.

An efficient and transition-metal-free method for the synthesis of the structurally diversified trifluoroethylthiol phenanthridines and 3,4-dihydroisoquinolines is described. Various 2-isothiocyanobiaryls and aryl alkyl isothiocyanates reacted with phenyl(2,2,2-trifluoroethyl)iodonium triflate in CH2Cl2 in the presence of trifluoromethanesulfonic acid at 40 °C to form the corresponding trifluoroethylation/cyclization products in good to quantitative yields. This work represents the first construction of trifluoroethylthiol phenanthridine and isoquinoline derivatives from isothiocyanates in the absence of transition-metal catalysts by a one-pot procedure.