Water facilitated photolysis of perfluoroalkyl iodidesviahalogen bonding

Abstract

Sigma (σ)-hole effect of perfluoroalkyl iodide, an interaction between the σ* orbitals of C-I bond and a Lewis base, has proven efficient for the generation of perfluoroalkyl radicals via single...

Late‐Stage Photocatalytic Fluoroalkylation of Aromatic Crown Ethers in Aqueous Media

“…In this context, a water facilitated photolysis of perfluoroalkyl iodides via halogen bonding has been recently reported. [33] To demonstrate the scalability of the methodology herein reported, the fluoroalkylation of DB24 C8 was carried out on a gram-scale affording 65 % (0,98 g) isolated yield of product 16 (see SI for details). The utility of the methodology is further highlighted by the post-synthetic fluoroalkylation of a mechanically interlocked molecule (MIM) [34] such as [2]rotaxane 20.…”

Radical Perfluoroalkylation of Aliphatic Substrates

“…122 It has been confirmed that water facilitates the iodoperfluoroalkylation reaction of alkenes and alkynes via the formation of an EDA complex between water and the iodoperfluoroalkane, which upon excitation by visible light delivers the fluoroalkyl radical efficiently. 40 Very recently, Wang, Chen, Beller, and colleagues 44 disclosed the activation of R F −I bonds in the presence of KOH to generate R F radicals, which subsequently perform an ATRA reaction on alkenes and alkynes. The scope of the reaction is illustrated in Scheme 33A.…”

“…The iodoperfluoroalkylation reaction has also been performed in water by direct irradiation of perfluoroalkyl iodides in the presence of alkenes and alkynes, or more recently by Rose Bengal photocatalysis . It has been confirmed that water facilitates the iodoperfluoroalkylation reaction of alkenes and alkynes via the formation of an EDA complex between water and the iodoperfluoroalkane, which upon excitation by visible light delivers the fluoroalkyl radical efficiently …”

“…Perfluoroalkyl iodides R F –I, which have a deep σ-hole, form electron donor–acceptor complexes (EDA complexes) with Lewis bases (LB) via halogen bonding (XB); , upon visible light irradiation, an electron transfer (SET) process is induced from the LB electron pair to the σ*-antibonding orbital of R F –I, giving the corresponding R F radicals. Small organic molecules or ionic species such as amines, enamines, carbonyl compounds, , phosphines, , phosphates, hydroquinones, chloride ions, or even H 2 O , can serve as organic catalysts that form EDA complexes with perfluoroalkyl iodides. − Very recently, bases such as K t OBu and HO – were shown to activate R F –I bonds very conveniently to produce R F radicals upon illumination Chart illustrates an EDA complex-driven photoinitiation that delivers the reacting radical upon the decomposition of the respective radical anion (A = R F –I).…”

Expanding Reaction Profile of Allyl Carboxylates via 1,2-Radical Migration (RaM): Visible-Light-Induced Phosphine-Catalyzed 1,3-Carbobromination of Allyl Carboxylates

“…Nevertheless, DFT and TD-DFT calculations revealed that (i) the formation of the dppm– 2a complex ( I ) is enthalpically favored by −3.6 kcal/mol and is endergonic by only 6.6 kcal/mol (Figure H) and (ii) different conformers of complex I and their Na 2 CO 3 adducts have absorptions extending into the visible light region (Figures S14–S16). , These conformers and adducts are higher in energy and may exist at concentrations outside the detection limit of the UV–Vis spectrometer.…”