Organophosphine-Catalyzed Difluoroalkylation of Alkenes

Zhao, Liang; Huang, Yang; Wang, Ze; Zhu, Erlin; Mao, Ting; Jia, Jia; Gu, Jiwei; Li, Xiaofei; He, Chun‐Yang

doi:10.1021/acs.orglett.9b02314

Cited by 53 publications

(23 citation statements)

References 51 publications

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“…In the latter case, the formation of a halogen bond between the electron-deficient perfluoroalkyl iodide and a suitable Lewis base results in homolytic bond cleavage upon irradiation of visible light. Amines [28][29][30][31][32][33], phenols [34], ketones [35,36], as well as phosphines [37][38][39][40][41] have been reported for this purpose in either stoichiometric or catalytic quantities.…”

Section: Introductionmentioning

confidence: 99%

Visible Light-Induced Homolytic Cleavage of Perfluoroalkyl Iodides Mediated by Phosphines

et al. 2020

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In an effort to explain the experimentally observed variation of the photocatalytic activity of t Bu 3 P, n Bu 3 P and (MeO) 3 P in the blue-light regime [Helmecke et al., Org. Lett. 21 (2019) 7823], we have explored the absorption characteristics of several phosphine– and phosphite–IC 4 F 9 adducts by means of relativistic density functional theory and multireference configuration interaction methods. Based on the results of these computational and complementary experimental studies, we offer an explanation for the broad tailing of the absorption of t Bu 3 P-IC 4 F 9 and (MeO) 3 P-IC 4 F 9 into the visible-light region. Larger coordinate displacements of the ground and excited singlet potential energy wells in n Bu 3 P-IC 4 F 9 , in particular with regard to the P–I–C bending angle, reduce the Franck–Condon factors and thus the absorption probability compared to t Bu 3 P-IC 4 F 9 . Spectroscopic and computational evaluation of conformationally flexible and locked phosphites suggests that the reactivity of (MeO) 3 P may be the result of oxygen lone-pair participation and concomitant broadening of absorption. The proposed mechanism for the phosphine-catalyzed homolytic C–I cleavage of perfluorobutane iodide involves S1 ← S0 absorption of the adduct followed by intersystem crossing to the photochemically active T 1 state.

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Section: Introductionmentioning

confidence: 99%

Visible Light-Induced Homolytic Cleavage of Perfluoroalkyl Iodides Mediated by Phosphines

et al. 2020

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“…However, the transformation of demanding alkenes or terminal alkynes was not substantially improved. Only in the case of phenylacetylene (Table 1, entry 4) a better yield was obtained by by changing the Lewis acid from B(C 6 F 5 ) 3 (2) to B(2,6-F 2 C 6 H 3 ) 3 (21). With respect to the phosphine catalyst partner, we found that only t Bu 3 P (1) promoted the reaction efficiently.…”

Section: Scheme 5 Flp-catalyzed Iodoperfluoroalkylation Of Alkenes Inmentioning

confidence: 87%

“…27 We assumed that this formation of a stable [ t Bu 3 PH][PhC≡CB(C 6 F 5 )] intermediate might be a faster and more efficient process than the iodoperfluoroalkylation of the alkyne. To overcome this problem of potential catalyst deactivation and potentially improving tolerance towards heteroatoms, electronically tuned boranes such as tris(2,6-difluorophenyl)borane (21) and the more water-stable (2,3,6-trichlorophenyl)bis(2,3,6trifluorophenyl)borane (22) were investigated ( Table 1 and Table 2). However, the transformation of demanding alkenes or terminal alkynes was not substantially improved.…”

Section: Scheme 5 Flp-catalyzed Iodoperfluoroalkylation Of Alkenes Inmentioning

confidence: 99%

“…Zhao, Li and He developed a difluoroalkylation of alkenes by using organophosphine reagents (DPPM) at higher temperature. 21 Zhang and co-workers presented the phosphine-catalyzed difluoroalkylation of arenes and heterocycles by using visible light. 22 The group of Dilman successfully developed the iododifluoromethyla-tion of alkenes by utilizing (phosphonio)-difluoromethyl radical cations.…”

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confidence: 99%

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Metal-Free Iodoperfluoroalkylation: Photocatalysis versus Frustrated Lewis Pair Catalysis

Helmecke

Spittler²,

Schmidt³

et al. 2020

Synthesis

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A comparison of two catalytic, metal-free iodoperfluoroalkylation protocols is presented. Frustrated Lewis pairs [ t Bu3P/B(C6F5)3] or phosphines/phosphites under visible light irradiation efficiently mediate the functionalization of non-activated alkenes and alkynes. A comprehensive account of the corresponding substrate scopes as well as insights into the mechanistic details of both reaction pathways are provided.

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“…Very recently, non-covalent interaction initiated fluoroalkylation reaction has emerged as an attractive strategy [37][38][39][40][41][42][43][44][45][46][47]. Inspired by our previous studies in this field [48][49][50][51], we envision that if the solvent can serve as an electron donor compound, the reactions would be simpler. Here, we demonstrate a…”

Section: Introductionmentioning

confidence: 99%

Visible-light Promoted Atom Transfer Radical Addition−Elimination (ATRE) Reaction for the Synthesis of Fluoroalkylated Alkenes Using DMA as Electron-donor

Wang

Mao

et al. 2020

Molecules

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Here, we describe a mild, catalyst-free and operationally-simple strategy for the direct fluoroalkylation of olefins driven by the photochemical activity of an electron donor−acceptor (EDA) complex between DMA and fluoroalkyl iodides. The significant advantages of this photochemical transformation are high efficiency, excellent functional group tolerance, and synthetic simplicity, thus providing a facile route for further application in pharmaceuticals and life sciences.Molecules 2020, 25, 508 2 of 8 mild, catalyst-free and operationally-simple strategy for the direct fluoroalkylation of olefins driven by the photochemical activity of electron donor−acceptor (EDA) complex between DMA and fluoroalkyl iodides. The significant advantages of this photochemical transformation are high efficiency, excellent functional group tolerance, and synthetic simplicity [52].

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Organophosphine-Catalyzed Difluoroalkylation of Alkenes

Cited by 53 publications

References 51 publications

Visible Light-Induced Homolytic Cleavage of Perfluoroalkyl Iodides Mediated by Phosphines

Visible Light-Induced Homolytic Cleavage of Perfluoroalkyl Iodides Mediated by Phosphines

Metal-Free Iodoperfluoroalkylation: Photocatalysis versus Frustrated Lewis Pair Catalysis

Visible-light Promoted Atom Transfer Radical Addition−Elimination (ATRE) Reaction for the Synthesis of Fluoroalkylated Alkenes Using DMA as Electron-donor

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