Visible-light-mediated trifluoroethylation of 2-isocyanobiaryl with trifluoroethyl iodide: Synthesis of 6-trifluoroethyl-phenanthridines

Synthesis of 6-Trichloromethylphenanthridines by Transition Metal-Free Radical Cyclization of 2-Isocyanobiphenyls

“…It has been reported that the addition of bases has a positive impact on the cyclization of 2-isocyanobiphenyls. ,,,,,, Consequently, the effect of base was investigated. A slight decrease of the yield was observed in the absence of a base (Table , entry 7) as well as the use of NaOH and NaHCO 3 (Table , entries 8 and 9).…”

“…Recently, an efficient synthetic approach to C6 functionalized phenanthridines has been developed based on the strategy of radical addition and subsequent cyclization of 2-isocyanobiphenyl species. In this context, many radical precursors have been reported, such as boronic acids, trifluoromethylating reagents, difluoromethyl sources, fluorinated sulfones, fluorinated alkyl iodides, aldehydes, acyl or alkyl peroxides, simple alkanes, halides, diarylphosphine oxides, aryl sulfonyl chlorides, α-oxocarboxylic acids, hydrazines, disulfides, thiols, ethers, amines, unsaturated ketoximes, and N -alkyl amides . Among them, the transition-metal-free procedure is more favorable owing to the strict restriction on the residual amount of heavy metals in pharmaceutical industry.…”

Recent Advances in the Trifluoromethylation Reactions of Isonitriles To Construct CF3-Substituted N-Heterocycles

“…Fu, Zou, and co-workers also in 2014 reported that the visible-light-induced, iridium-catalyzed reaction of 2-isocyanobiphenyls with 2,2,2-trifluoroethyl iodide the pres-ence of fac-Ir(ppy) 3 photocatalyst gave 6-(2,2,2-trifluoroethyl)phenanthridine derivatives. 16 In 2013, Zhou and co-workers used the Ruppert-Prakash reagent in the synthesis of 6-(trifluoromethyl)phenanthridines (Scheme 6). 17 This efficient transitionmetal-free approach from 2-isocyanobiphenyls with TM-SCF 3 mediated the oxidative cyclization using PhI(OAc) 2 , NaOAc as a base, and catalytic benzoquinone (BQ) to give 6-(trifluoromethyl)phenanthridines in 41-87% yields.…”

Photocatalytical and Photochemical Generation of Imidoyl Radicals: Synthetic Applications

“…73 Similarly, again in 2014, Fu et al described Ircatalysed isocyanide insertion reaction of 2-biphenyl isocyanides 1 with trifluoroethyl iodide 102 to afford 6-trifluoroethyl-phenanthridine derivatives 103 under the visible-light irradiation (Scheme 23). [60] A variety of trifluoroethylated scaffolds were obtained in good to excellent yields with high functional group tolerance under mild reaction conditions. The mechanism of the reaction remained essentially similar to the one shown in Scheme 22.…”