Trifluoromethylation of heterocycles via visible light photoredox catalysis

Iqbal, Naeem; Choi, Sungkyu; Ko, Euna; Cho, Eun Jin

doi:10.1016/j.tetlet.2012.02.032

Cited by 197 publications

(72 citation statements)

References 49 publications

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“…Given that radical species could be generated from trifluoromethanesulfonyl chloride [19] or aryl diazolium salt [20] under visible-light photoredox conditions, it is possible to realize trifluoromethylation and arylation based on our proposed mechasim (Scheme 2). Indeed, trifluoromethylation of enamides could be achieved under slightly modified standard conditions.…”

Section: Resultsmentioning

confidence: 99%

Direct CH Functionalization of Enamides and Enecarbamates by Using Visible‐Light Photoredox Catalysis

Jiang

Huang

Guo

et al. 2012

Chemistry A European J

181

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Direct C-H functionalization of various enamides and enecarbamates was realized through visible-light photoredox catalyzed reactions. Under the optimized conditions using [Ir(ppy)(2)(dtbbpy)PF(6)] as photocatalyst in combination with Na(2)HPO(4), enamides such as N-vinylpyrrolidinone could be easily functionalized by irradiation of the reaction mixture overnight in acetonitrile with visible light. The scope of the reaction with respect to enamide and enecarbamate substrates by using diethyl 2-bromomalonate for the alkylation reaction was explored, followed by an investigation of the scope of alkylating reagents used to react with the enamides and enecarbamates. The results indicated that reaction takes place with quite broad substrate scope, however, tertiary enamides with an internal C=C double bond in the E configuration could not be alkylated. Alkylation of N-vinyl tertiary enamides and enecarbamates gave monoalkylated products exclusively in the E configuration. Alkylation of N-vinyl secondary enamides gave doubly alkylated products. Double bond migration was observed in the reaction of electron-deficient bromides such as 3-bromoacetyl acetate with N-vinylpyrrolidinone. A mechanism is proposed for the reaction that is different from reported reactions of SOMOphiles with a nonfunctionalized C=C double bond. Further tests on the trifluoromethylation and arylation of enamides and enecarbamates under similar conditions showed that the reactions could serve as a mild, practical, and environmentally friendly approach to various functionalized enamides and enecarbamates.

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Section: Resultsmentioning

confidence: 99%

Direct CH Functionalization of Enamides and Enecarbamates by Using Visible‐Light Photoredox Catalysis

Jiang

Huang

Guo

et al. 2012

Chemistry A European J

181

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“…A variety of reagents, such as CF 3 I, 50,[55][56][57]59,62,66,67 silver trifluoroacetate, triflyl chloride (CF 3 SO 2 Cl), 49,64 the Langlois reagent, the Togni reagent, 51,53,54,60,65 the Umemoto reagent, 48,52,58,63,65 and the Shibata reagent, 61 can act as trifluoromethyl radical (•CF 3 The excited catalyst can reduce the R f X source (oxidative quenching pathway), regeneration of the catalyst follows by means of an electron donor or else, the photoexcited catalyst could be reduced by an electron donor to a one-electron reduced species that transfers an extra electron to the R f X source (reductive quenching pathway).…”

Section: Introductionmentioning

confidence: 99%

“…: [Ru(bpy) 3 ] 2+ and facIr(ppy) 3 (bpy = 2,2´-bipyridine and ppy = 2-phenylpyridinate), can induce both oxidative 48,49,51,54,58,60,[63][64][65] and reductive 50,[55][56][57]59,62 quenching cycles, owed to the positive driving forces for electron transfer to typical perfluoroalkyl halides. 7 The competition of the two pathways precludes the elucidation of the molecular parameters of the catalysis.…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic fluoroalkylation reactions of organic compounds

2015

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“…In particular, trifluoromethylated compounds are characterized by superior metabolic stability, binding selectivity, bioavailability and lipophilicity compared with those of their nontrifluoromethylated analogues, and these characteristics have stimulated the intensive development of new pharmaceutical and agrochemical agents bearing this moiety [3][4][5] . In general, transition-metal-catalysed cross-coupling reactions (for example, those involving Cu, Pd, Ru or Ir) are regarded as state-of-the-art methods for C-CF 3 bond formation [6][7][8][9][10][11][12][13][14][15][16][17][18] . However, these transition-metal-catalysed reactions pose their own challenges.…”

mentioning

confidence: 99%

Hydrotrifluoromethylation and iodotrifluoromethylation of alkenes and alkynes using an inorganic electride as a radical generator

et al. 2014

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The trifluoromethyl (CF 3 ) group is a staple synthon that can alter the physical and chemical properties of organic molecules. Despite recent advances in trifluoromethylation methods, the development of a general synthetic methodology for efficient and selective trifluoromethylation remains an ongoing challenge motivated by a steadily increasing demand from the pharmaceutical, agrochemical and materials science industries. In this article, we describe a simple, efficient and environmentally benign strategy for the hydrotrifluoromethylation of unactivated alkenes and alkynes through a radical-mediated reaction using an inorganic electride, [Ca 2 N] þ Á e À , as the electron source. In the transformation, anionic electrons are transferred from [Ca 2 N] þ Á e À electrides to the trifluoromethylating reagent CF 3 I to initiate radical-mediated trifluoromethylation. The role of ethanol is pivotal in the transformation, acting as the solvent, an electron-releasing promoter and a hydrogen atom source. In addition, iodotrifluoromethylation of alkynes proceeds selectively upon the control of electride amount.

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Trifluoromethylation of heterocycles via visible light photoredox catalysis

Cited by 197 publications

References 49 publications

Direct CH Functionalization of Enamides and Enecarbamates by Using Visible‐Light Photoredox Catalysis

Direct CH Functionalization of Enamides and Enecarbamates by Using Visible‐Light Photoredox Catalysis

Photocatalytic fluoroalkylation reactions of organic compounds

Hydrotrifluoromethylation and iodotrifluoromethylation of alkenes and alkynes using an inorganic electride as a radical generator

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