Synthesis and Regioselective N‐2 Functionalization of 4‐Fluoro‐5‐aryl‐1,2,3‐NH‐triazoles

Abstract

A new efficient synthetic route to 4‐fluoro‐5‐aryl‐1,2,3‐NH‐triazoles was elaborated. The reactions of NaN3 with aryl‐substituted α‐fluoronitroalkenes resulted in the domino construction of the target fluorinated triazoles. Sulfamic acid is an effective promoter for this heterocyclization. The subsequent functionalization reactions of the obtained triazoles proceed highly regioselectively at the N‐2 position. The observed regioselectivity was supported by DFT calculations.

Green, Catalyst‐Free Reaction of Indoles with β‐Fluoro‐β‐nitrostyrenes in Water

“…The starting 2‐fluoro‐2‐nitrostyrenes were prepared according to the reported procedures ,. [8f] Compounds 1a , 1b , 1e , 1f , 1g , and 1h are known compounds.…”

“…Similarly to their non‐fluorinated analogues, β‐fluoro‐β‐nitrostyrenes have a very polar C–C double bond due to the presence of a strongly electron‐withdrawing nitro group. These molecules are very attractive Michael acceptors that can be used to construct molecules with one fluorine atom in the structure . This study is devoted to the reaction of β‐fluoro‐β‐nitrostyrenes with various indoles.…”

Fluorinated 1,2,3-Triazoles from α-Fluoronitroalkenes as Surrogates of α-Fluoroalkynes via Regioselective Cycloaddition Reactions with Organic Azides

“…Spectroscopic data for 1-SM-d are consistent with previously reported data for this compound. [17] 1-(2-Bromo-2-fluorovinyl)-4-(tert-butyl)benzene (1-SM-e): 4-(tert-Butyl)benzaldehyde (500 mg, 3.08 mmol), PPh3 (2.43 g, 9.25 mmol) and CFBr3 (0.39 mL, 4.01 mmol). The product was purified by flash column chromatography using petroleum ether as an eluent to afford 1-SM-e in (0.67 g, E/Z = 60:40) 84% yield as a colorless liquid.…”

“…Spectroscopic data for 1 are consistent with previously reported data for this compound. [17] Fe(NO 3 ) 3 . Spectroscopic data for 1a are consistent with previously reported data for this compound.…”

“…Spectroscopic data for 1b are consistent with previously reported data for this compound. [17] (Z)-4-(2-Fluoro-2-nitrovinyl)benzonitrile (1c): 4-(2-bromo-2-fluorovinyl)benzonitrile (500 mg, 2.2 mmol), tris(nitrooxy)iron nonahydrate (2.6 g, 6.6 mmol) The product was purified by column chromatography (EtOAc/Petroleum Ether = 9:1 as eluent) affording 1c (0.38 g, 89% yield) as an off white solid. .…”