Dual-gold(I)-generated trifluoromethylation of terminal alkynes with Togni’s reagent

Electrochemical trifluoromethylation of alkynes: the unique role of DMSO as a masking auxiliary

Recent advancements in eco-friendly radical fluoroalkylation have substituted traditional two-electron-based reactions. However, the radical trifluoromethylation of terminal alkynes remains a significant challenge, primarily due to the high reactivity of alkenyl radical intermediates, which predominantly engage in reactions other than the desired elimination. In this work, we have developed an electrochemical trifluoromethylation method for terminal alkynes, facilitating the efficient formation of CF3-alkynes. The success of this method centers on the use of DMSO as a "masking auxiliary", which effectively stabilizes the alkenyl radical intermediate, allowing the reaction to proceed smoothly under mild conditions. This approach is supported by extensive experimental and computational studies, which elucidate the unique mechanism and expand the potential applications of radical trifluoromethylation across chemical synthesis.

Fe-Catalyzed Radical Trifluoromethyl-Alkenylation of Alkenes or Alkynes with 2-Amino-1,4-naphthoquinones

The first Fe-catalyzed three-component radical trifluoromethyl-alkenylation of alkenes with 2-amino-1,4-naphthoquinones and CF₃SO₂Na is reported. The developed reaction enables the highly regioselective preparation of a variety of valuable CF₃-substituted 1,4-naphthoquinones in acceptable yields. In the light of the catalytic system, alkynes smoothly afford the corresponding three- or four-component trifluoromethyl-alkenylation products. This protocol features use of easily available and inexpensive reagents, broad substrate scope, and simple reaction conditions.

Silver-Mediated Perfluoroalkylation of Terminal Alkynes with Perfluoroalkyl Iodides

The incorporation of a perfluoroalkyl group (R_F) into drug candidates has become an increasingly important strategy in drug molecule design. In this study, the silver-mediated perfluoroalkylation reaction based on the addition-elimination process of terminal alkynes which was initiated by a perfluoroalkyl radical to form a C(sp)-R_F bond has been developed. The reaction proceeds under mild conditions using readily available, low-cost perfluoroalkyl iodides as the sources of the R_F group. This method allows access to a variety of perfluoroalkylated alkynes.

Dinuclear gold(i) complexes: from bonding to applications

The last two decades have seen a veritable explosion in the use of gold(i) complexes bearing N-heterocyclic carbene (NHC) and phosphine (PR₃) ligands.

A Tunable Trifluoromethyliodonium Reagent

Four complexes of MCl₄ (M=Ti, Zr, Hf) with the hypervalent trifluoromethyl iodine reagent trifluoromethyl-1,3-dihydro-3,3-dimethyl-1,2-benziodoxole (1,=L) are described. With TiCl₄ , an I-O bond cleavage occurs, leading to the formation of the trifluoromethyliodonium alcoholate complexes [Ti₂ Cl₆ (L)₄ ]Cl₂ (2 a) and Ti₂ Cl₈ (L) (2 b). Reactions with ZrCl₄ and HfCl₄ form the complexes ZrCl₄ (L)₂ (3) and HfCl₄ (L)₂ (4), respectively, wherein the original I-O bond is retained and elongated compared to that in free 1. Therefore, the reactivity of 1 can be easily and practically fine-tuned by addition of different metal chlorides, following the order ZrCl₄ /HfCl₄ <TiCl₄ <2 TiCl₄ . Complexes 2 a, 3, and 4 are remarkably bench-stable forms of activated reagent 1, while 2 b is readily accessible in situ. 2 a and 2 b represent the first "real" trifluoromethyliodonium reagents derived from iodanes, that is, with the I-O bond being completely cleaved. The new complexes were shown to be useful for the trifluoromethylation of para-toluenesulfonate under aprotic conditions.