Nickel-Catalyzed Cross-Electrophile Ring Opening/gem-Difluoroallylation of Aziridines

Abstract

Herein we report a nickel-catalyzed regioselective cross-electrophile ring opening reaction of sulfonyl-protected aziridines with trifluoromethyl-substituted alkenes as the gem-difluoroallylating agents, providing a new and efficient entry to prepare gem-difluorobishomoallylic sulfonamides. Moreover, the scaffold of 6-fluoro-1,2,3,4-tetrahydropyridine can be constructed starting from the ring opening products via NaH-mediated intramolecular defluorinative nucleophilic vinylic substitution.

Magic Blue-Initiated SN2-Type Ring Opening of Activated Aziridines: Friedel–Crafts-Type Alkylation of Electron-Rich Arenes/Heteroarenes

“…The ring-opening transformation of aziridines is another way to prepare arylethylamines. Various catalytic ring-opening reactions have been developed including transition metal-catalyzed C-arylations of aziridines, Cu(I)-catalyzed/NaHMDS-mediated ring opening of aziridine with pyridyl Grignard/ketene silyl acetals/2-azaallyl anion nucleophiles, ,, Cu(I)-catalyzed enantioselective Friedel–Crafts alkylation of indoles with activated aziridines, cooperative Brønsted/Lewis acid-catalyzed ring opening of aziridine with organotrifluoroborates, Pd(II)-/Ni(II)-catalyzed reductive cross-coupling with aryl boronic acids/aryl iodides, Pd/NHC-catalyzed Suzuki–Miyaura arylation, and Ni(II)-catalyzed Negishi alkylations/cross-electrophilic ring opening of aziridines. Photoredox, C–H activation, electrochemical approach, and some transition metal-free approaches for the ring opening of aziridines have also been developed by various groups.…”

Visible Light‐Mediated Defluorination to Access 1,1‐Difluoro‐1,3‐Enynes

“…[11][12] For example, the addition of the radicals produced from diverse precursors to alkenes containing CF 3 , followed by the β-F elimination is one of the efficient methods. [13][14][15][16][17][18][19][20][21][22][23][24] However, the scope of alkenes was mainly concentrated on aryl alkenes.…”

Nickel-catalyzed hydrodefluorination/deuterodefluorination of CF3-alkenes with formic acid

“…Defluorinative reactions of more easily available CF 3 -substituted alkenes via anionic S N 2′-type 5,6 and radical-type 7–10 substitution offer a unique approach to access gem -difluoroalkenes. Compared to other nucleophilic reagents (carbon, boron, and nitrogen), replacing fluorine with hydrogen (known as hydrofluorination) is more challenging due to competing multiple defluorination or hydrogenation side reactions.…”