Flash generation and borylation of 1-(trifluoromethyl)vinyllithium toward synthesis of α-(trifluoromethyl)styrenes

Thermally unstable (3,3,3-trifluoroprop-1-en-2-yl)lithium was generated by lithiation of 2-bromo-3,3,3-trifluoroprop-1-ene and successively underwent borylation in a flow microreactor system. Direct use of the 1-(trifluoromethyl)vinylborate thus formed for the Suzuki–Miyaura coupling in a batch system afforded α-(trifluoromethyl)styrenes in high yields

Ni-Catalyzed Synthesis of Fluoroarenes via [2+2+2] Cycloaddition Involving α-Fluorine Elimination

A method for direct synthesis of tetrasubstituted fluoroarenes via nickel-catalyzed [2+2+2] cycloaddition is presented. The reaction combines one molecule of 1,1-difluoroethylene with two molecules of alkynes and involves sequential cleavage of the C[BOND]F and C[BOND]H bonds in difluoroethylene. The catalytic cycle is established by reduction of the intermediary NiII fluoride with a triethylborane-based borate

Nickel-Catalyzed Allylic C(sp³)–F Bond Activation of Trifluoromethyl Groups via β‑Fluorine Elimination: Synthesis of Difluoro-1,4-dienes

The nickel-catalyzed defluorinative coupling of 2-trifluoromethyl-1-alkenes and alkynes with the aid of Et₃SiH provides 1,1-difluoro-1,4-dienes under mild reaction conditions. This reaction involves selective allylic C­(sp³)–F bond activation via β-fluorine elimination from nickelacyclopentenes

Platform for Ring-Fluorinated Benzoheterole Derivatives: Palladium-Catalyzed Regioselective 1,1-Difluoroallylation and Heck Cyclization

The synthesis of difluoromethylene-containing heterocycles was achieved via the palladium-catalyzed 1,1-difluoroallylation of heteronucleophiles followed by intramolecular Heck reaction. The allylic substitution of 3-bromo-3,3-difluoropropene was regioselectively accomplished by heteronucleophiles without rearrangement to give the corresponding 1,1-difluoroallylated compounds whose Heck cyclization proceeded in a 5-<i>exo</i> manner to afford ring-difluorinated indolines and dihydrobenzofurans. Their defluorinative allylic substitution further provided 2-fluoroindoles and 2-fluorobenzofurans