Photoinduced Ligand-to-Metal Charge Transfer (LMCT) of Fe Alkoxide Enabled C-C Bond Cleavage and Amination of Unstrained Cyclic Alcohols

Photoredox Iron-Catalyzed Decarboxylative Radical Cyclization for the Synthesis of Oxindoles and Chroman-4-ones

A sustainable, photocatalytic approach for the synthesis of oxindoles and chroman-4-ones was developed using carboxylate salts as radical precursors and FeCl3 as a catalyst. The reaction proceeds via a decarboxylative radical cyclization mechanism triggered by ligand-to-metal charge transfer under visible light irradiation, operating efficiently at room temperature. This method demonstrates excellent substrate scope, including the use of various alkyl carboxylates, and functional group tolerance and offers a scalable pathway for gram-scale synthesis, highlighting its practical application.

Catalysis in the Excited State: Bringing Innate Transition Metal Photochemistry into Play

Transition metal catalysis is an indispensable tool for organic synthesis that has been harnessed, modulated, and perfected for many decades by careful selection of metal centers and ligands, giving rise to synthetic methods with unparalleled efficiency and chemoselectivity. Recent developments have demonstrated how light irradiation can also be recruited as a powerful tool to dramatically alter the outcome of catalytic reactions, providing access to innovative pathways with remarkable synthetic potential. In this context, the adoption of photochemical conditions as a mainstream strategy to drive organic reactions has unveiled exciting opportunities to exploit the rich excited-state framework of transition metals for catalytic applications. This Perspective examines advances in the application of transition metal complexes as standalone photocatalysts, exploiting the innate reactivity of their excited states beyond their common use as photoredox catalysts. An account of relevant examples is dissected to provide a discussion on the electronic reorganization, the orbitals involved, and the associated reactivity of different types of excited states. This analysis aims to provide practitioners with fundamental principles and guiding strategies to understand, design, and apply light-activation strategies to homogeneous transition metal catalysis for organic synthesis.

Photocatalyzed Dehydration of 1-Aryl-1,2-Ethanediols to Methyl Ketones Driven by Eosin Y Fragmentation Products

Herein, we report a mild photocatalytic redox-neutral dehydration of aryl-1,2-ethanediols forming the respective methyl ketones. In the proposed mechanistic cycle an initial hydrogen atom abstraction (HAT) is followed by a 1,2-spin center shift (SCS) as key steps. Interestingly, Eosin Y was found to act as a pre-catalyst dissociating into a catalytically active mixture under irradiation. To the best of our knowledge, this exemplifies the first synthetic utilization of Eosin Y degradation products. As a result, our reaction can be realized with a single organic photocatalyst and releases water as a sole by-product.

Ferric Nitrate as a Bifunctional Catalyst for Dehydration and Oxidative Cleavage-Esterification of Tertiary Alcohols

The selective oxidative cleavage and functionalization of C(OH)-C bonds in tertiary alcohols harbor immense feasibility in organic synthesis and enable the production of high value-added chemicals from renewable biomass. However, it remains a challenge, owing to the inherent kinetic inertness and thermodynamic stability of C(OH)-C bonds and the lack of Cα-H. Taking the huge potential and challenge of C(OH)-C bond activation and functionalization into consideration, herein, we show the first example of an inexpensive bifunctional ferric nitrate catalyst for catalytic direct oxidation of structurally distinct tertiary alcohols to esters with environmentally benign molecular oxygen as an oxidant and MeOH as a solvent, without the assistance of any additives. Detailed mechanistic studies reveal that this tandem catalytic oxidative process is initiated by the synergistic effects of an iron ion and nitrate ion, which serve as Lewis acids for dehydrating and a nitrogen dioxide radical precursor for inducing an oxidative cleavage, respectively.

Cobalt catalysed cross-dehydrogenative coupling of indoles: a photoinduced ligand to metal charge transfer process

We demonstrate the participation of cobalt in a photoinduced ligand-to-metal charge transfer process, which leads to the formation of ligand-based radical species and enables both homo and hetero cross-dehydrogenative coupling of indoles with decent yield at room temperature. This photo-induced LMCT process is substantiated by a series of mechanistic investigations.

Iron-Catalyzed Aerobic Carbonylation of Methane via Ligand-to-Metal Charge Transfer Excitation

The integration of ligand-to-metal charge transfer (LMCT) catalytic paradigms with radical intermediates has transformed the selective functionalization of inert C-H bonds, facilitating the use of nonprecious metal catalysts in demanding transformations. Notably, aerobic C-H carbonylation of methane to acetic acid remains formidable due to the rapid oxidation of methyl radicals, producing undesired C1 oxygenates. We present an iron terpyridine catalyst utilizing LMCT to achieve exceptional C2/C1 selectivity through synergistic photoexcitation, methyl radical generation, and carbonylation. Mechanistic studies highlight the critical roles of Fe(II) and Fe-carbonyl complexes in bypassing methyl radical oxidation via a radical rebound-like pathway, unlocking unprecedented efficiency in methane aerobic carbonylation.

Photoinduced Lignin Cα-Cβ Bond Cleavage and Chemodivergent Functionalization via Iron Catalysis

The photocatalytic conversion of lignin into value-added chemicals especially those functionalized molecules represent one of the most important strategies for sustainable and environmental-friendly development. Cleavage of C-C bonds in lignin under mild photocatalytic conditions for refining lignin into useful molecules is meaningful but challenging. Meanwhile, the assembly of diverse functional groups into active lignin fragments during the depolymerization is of great challenging. Herein, using cheap iron catalysts under visible light irradiation, the highly selective and efficient cleavage of Cα-Cβ bond in lignin is realized via ligand-to-metal charge transfer (LMCT) and hydrogen atom transfer (HAT) processes. The subsequent divergent functionalization of generated lignin fragment-based radical intermediates enables an efficient formation of diverse functionalized molecules. This method is also effective for cleavage of Cα-Cβ bond in native lignin, yielding two identified benzaldehyde monomers in a total yield of 8.7 wt %.

Photochemical upcycling of polymers via visible light-driven C-H bond activation

The excessive use and improper disposal of plastics have placed a significant burden on the environment. To mitigate this impact, prioritizing the chemical upcycling of plastics is crucial. Unlike traditional thermochemical upcycling, which requires harsh conditions such as high temperatures and pressures, photochemical upcycling is viewed as a more environmentally friendly and cost-effective alternative. This includes using light to promote C-H bond activation to achieve the oxidative degradation of plastics, generating various valuable small molecules, or employing light-induced C-H bond activation for post-polymerization modification of post-consumer plastics to obtain polymers with enhanced properties. These methods are highly attractive approaches within the realm of chemical upcycling. This mini-review highlights the scientific breakthroughs in upcycling polymers through oxidative degradation and post-polymerization modification via visible light-driven C-H bond activation. In addition, the reaction mechanism compatibility as well as practical application have been emphatically discussed.

Dual ligand-enabled iron and halogen-containing carboxylate-based photocatalysis for chloro/fluoro-polyhaloalkylation of alkenes

Herein, we demonstrate a practical dual ligand-enabled iron photocatalysis paradigm-converting all kinds of halogen-containing carboxylates (C n X m COO-, X: F, Cl, Br) into C n X m radicals for the valuable chloro/fluoro-polyhaloalkylation of non-activated alkenes with easily available trichloroacetonitrile/Selectfluor as the electrophilic halogenation reagent. The modular in situ assembly of the effective iron and C n X m COO--based light-harvesting species using the two ligands-OMe/CF3-substituted bipyridine and acetonitrile/trichloroacetonitrile is evidenced by detailed mechanistic studies. The late-stage modification, low loading amount of iron (TON: 257) and feasible gram-scale synthesis show the utility of this protocol. We thus anticipate that the dual ligand-enabled iron photocatalysis paradigm may facilitate activation and transformation of inert bulk chemicals.

Photoinduced Deconstructive Alkylation Approach Enabled by Oxy-Radicals from Alcohols

Alcohols are the most commercially abundant, synthetically versatile and operationally convenient functional groups in organic chemistry. Therefore, a strategy that utilizes hydroxy-containing compounds to develop novel bond disconnection and formation process would achieve molecular diversity. Herein, a deconstructive strategy for the generation of quinoxalin-2(1H)-one derivatives has been developed from alcohol precursors via oxy-radical-induced β-fragmentation. Additionally, 1,5-HAT and deoxygenation by P(III) along with oxy-radical were demonstrated as alternative pathways for this transformation. Furthermore, with the deep-seated reorganization of a few terpenes carbon framework, a unique activity with inhibition against the growth of pathogenic fungi was observed.

Ring Transformation of Cyclopropenes to Benzo-Fused Five-Membered Oxa- and Aza-Heterocycles via a Formal [4+1] Cyclization

In the context of the growing importance of heterocyclic compounds across various disciplines, numerous strategies for their construction have emerged. Exploiting the distinctive properties of cyclopropenes, this study introduces an innovative approach for the synthesis of benzo-fused five-membered oxa- and aza-heterocycles through a formal [4+1] cyclization and subsequent acid-catalyzed intramolecular O- to N- rearrangement. These transformations exhibit mild reaction conditions and a wide substrate scope. The applications in the late-stage modification of complex molecules and in the synthesis of a potential PD-L1 gene down-regulator, make this method highly appealing in related fields. Combined experimental mechanistic studies and DFT calculations demonstrate Rh(III)-mediated sequential C─H coupling/π-allylation/dynamically favorable O-attack route.

Iron-Catalyzed Electrophotochemical α-Functionalization of a Silylcyclobutanol

Four-membered ring structure is important in organic chemistry, and selective cleavage and functionalization of these strained rings are of great interest. However, direct α-functionalization of cyclobutanols is rarely reported because of the high O-H bond dissociation energy and the occurrence of β-scission of C-C bonds in these alcohols. Recently, transition-metal catalysis has facilitated alkoxy radical generation. Herein, we report a method for electrophotochemical α-functionalization of a silylcyclobutanol via visible-light-induced LMCT reactions of M-alkoxy complexes. Introduction of the silyl group into the cyclobutanol structure favored fast [1,2]-silyl transfer over ring opening, thus allowing the generation of α-functionalized products.

Iron-Catalyzed Multicomponent C-H Alkylation of in Situ Generated Imines via Photoinduced Ligand-to-Metal Charge Transfer

Herein, we describe a novel photoinduced iron-catalyzed strategy for multicomponent C-H alkylation of in situ generated imines. By utilizing the alkyl radicals generated through iron-mediated photocatalytic C-H activation, the imines formed in situ are further subjected to addition reactions, resulting in the synthesis of various secondary and tertiary amine products. This method is simple to operate and does not require additional oxidants. It is applicable to inert alkane substrates such as cyclic alkanes, cyclic ethers, toluene, and ketones. The reaction is also compatible with various aromatic amines, alkyl amines, halogenated aromatic amines, as well as aromatic aldehydes, alkyl aldehydes, and cinnamaldehyde, among other different types of aldehydes.

Light-induced ligand-to-metal charge transfer of Fe(III)-OR species in organic synthesis

Light-induced ligand-to-metal charge transfer (LMCT) has been utilized as a powerful strategy in various organic reactions. First-row transition metals, especially iron complexes, show good applications in this process. Fe(III)-Cl and Fe(III)-OR species are two key intermediates involved in the LMCT of iron complexes. This review highlights studies on LMCT of Fe(III)-OR species, including carboxylate-iron and alkoxy-iron species, in organic transformations. Reaction conditions, substrate scope and related mechanisms are discussed.

Photoinduced Ligand-to-Metal Charge Transfer in Base-Metal Catalysis

The absorption of light by photosensitizers has been shown to offer novel reactive pathways through electronic excited state intermediates, complementing ground state mechanisms. Such strategies have been applied in both photocatalysis and photoredox catalysis, driven by generating reactive intermediates from their long-lived excited states. One developing area is photoinduced ligand-to-metal charge transfer (LMCT) catalysis, in which coordination of a ligand to a metal center and subsequent excitation with light results in the formation of a reactive radical and a reduced metal center. This mini review concerns the foundations and recent developments in ligand-to-metal charge transfer in transition metal catalysis focusing on the organic transformations made possible through this mechanism.

Synergistic use of photocatalysis and convergent paired electrolysis for nickel-catalyzed arylation of cyclic alcohols

The merging of transition metal catalysis with electrochemistry has become a powerful tool for organic synthesis because catalysts can govern the reactivity and selectivity. However, coupling catalysts with alkyl radical species generated by anodic oxidation remains challenging because of electrode passivation, dimerization, and overoxidation. In this study, we developed convergent paired electrolysis for the coupling of nickel catalysts with alkyl radicals derived from photoinduced ligand-to-metal charge-transfer of cyclic alcohols and iron catalysts, providing a practical method for site-specific and remote arylation of ketones. The synergistic use of photocatalysis with convergent paired electrolysis can provide alternative avenues for metal-catalyzed radical coupling reactions.

Iron-Catalyzed Photoredox Alcohol α-C-H Alkylation and Tandem Intramolecular Cyclization: Facile Access to Multisubstituted 2,3-Dihydrofurans and γ-Butyrolactones

Multisubstituted furans occupy a pivotal position within the realms of synthetic chemistry and pharmacological science due to their distinctive chemical configurations and inherent properties. We herein introduce a tandem difunctionalization protocol of alcohols for the efficient synthesis of multisubstituted 2,3-dihydrofurans and γ-butyrolactones through the combination of photocatalysis and iron catalysis under mild conditions. Photoredox alcohol α-C(sp3)-H activation and Pinner-type intramolecular cyclization are two key processes. This method features significant convenience, economic benefits, and environmental friendliness.

Organophotocatalytic Remote Thiocyanation Reaction via Ring-Opening Functionalization of Cycloalkanols

The remote C(sp3)-SCN bond formation via ring-opening functionalization of cycloalkanols with N-thiocyanatosaccharin as the precursor of SCN radicals and pyrylium salt as the organic photocatalyst under visible light has been developed. Thus, various terminal keto thiocyanates were prepared without transition metals and oxidants in moderate to good yields. The simplicity, wide substrate scope and mild conditions feature its synthetic application capability.

Photoelectrochemical Fe/Ni cocatalyzed C-C functionalization of alcohols

The simultaneous activation of reactants on the anode and cathode via paired electrocatalysis has not been extensively demonstrated. This report presents a paired oxidative and reductive catalysis based on earth-abundant iron/nickel cocatalyzed C-C functionalization of ubiquitous alcohols. A variety of alcohols (i.e., primary, secondary, tertiary, or unstrained cyclic alcohols) can be activated at very low oxidation potential of (~0.30 V vs. Ag/AgCl) via photoelectrocatalysis coupled with versatile electrophiles. This reactivity yields a wide range of structurally diverse molecules with broad functional group compatibility (more than 50 examples).

Ultrafast Events of Photoexcited Iron(III) Chloride for Activation of Benzylic C-H Bonds

The usage of rare-earth-metal catalysts in the synthesis of organic compounds is widespread in chemical industries but is limited owing to its environmental and economic costs. However, recent studies indicate that abundant-earth metals like iron(III) chloride can photocatalyze diverse organic transformations using blue-light LEDs. Still, the underlying mechanism behind such activity is debatable and controversial, especially in the absence of ultrafast spectroscopic results. To address this urgent challenge, we performed femtosecond time-resolved electronic absorption spectroscopy experiments of iron(III) chloride in selected organic solvents relevant to its photocatalytic applications. Our results show that the long-lived species [Fe(II) ← Cl•]* is primarily responsible for both oxidizing the organic substrate and reducing molecular oxygen through the diffusion process, leading to the final product and regenerating the photocatalyst rather than the most widely proposed free chloride radical (Cl•). Our study will guide the rational design of efficient earth-abundant photocatalysts.

Iron-Catalyzed Photochemical Synthesis of Sulfinamides from Aliphatic Hydrocarbons and Sulfinylamines

An iron-catalyzed photochemical sulfinamidation of hydrocarbons with N-sulfinylamines has been developed. The merger of ligand-to-metal charge transfer (LMCT) of FeCl3 with hydrogen atom transfer (HAT) process is the key for the generation of alkyl radicals from hydrocarbons, and the resultant alkyl radicals were readily trapped by N-sulfinylamines to produce structurally diverse sulfinamides. Contrary to traditional methods that inevitably use sensitive organometallic reagents and prefunctionalized substrates, our approach features simple operation and the wide availability of starting materials. Gratifyingly, the reaction is scalable, and the obtained sulfinamides can be conveniently converted to highly functionalized sulfur(VI) derivatives.

Iron-Catalyzed Csp2-Csp3 Cross-Coupling via Double Decarboxylation: One Step Synthesis of Remote Polar Alkenes

Herein, we report an efficient photoinduced iron-catalyzed strategy for cross-couplings of alkyl carboxylic and acrylic acids, which provides a powerful tool for the synthesis of a variety of alkenes with polar functional groups. This novel synthetic methodology can also be applied to the preparation of ketones by using α-keto acids. Mechanistic experiments revealed preliminary mechanistic details. Diverse functionalization could be achieved, which may help streamline the synthesis of complex analogues for drug discovery.

Selective α-oxidation of amides via visible-light-driven iron catalysis

Hydroxyl radicals (˙OH) as one of the highly reactive species can react unselectively with a wide range of chemicals. The ˙OH radicals are typically generated under harsh conditions. Herein, we report hydroxyl radical-induced selective N-α C(sp3)-H bond oxidation of amides under greener and mild conditions via an Fe(NO3)3·9H2O catalyst inner sphere pathway upon irradiation with a 30 W blue LED light strip (λ = 455 nm) using NaBrO3 as the oxidant. This protocol exhibited high chemoselectivity and excellent functional group tolerance. A preliminary mechanism investigation demonstrated that the iron catalyst afforded hydroxyl radicals via the visible-light-induced homolysis (VLIH) of iron complexes followed by a hydrogen atom transfer (HAT) process to realize this transformation.

Photoredox and NHC Enabled Deoxygenative Alcohol Homologation via Formal 1,2-Addition

A highly efficient photoinduced iron-catalyzed method has been developed for the direct use of alcohols as surrogates for organometallic reagents in the synthesis of tertiary alcohols. This method can be applied to both primary and secondary alcohols with diverse structures, enabling their reaction with aryl ketones under mild conditions. A variety of functional groups, including those that are typically reactive under conventional tertiary alcohol synthesis conditions, are compatible. Mechanistically, this reaction proceeds through the direct addition of the radical to the carbonyl pathway.

Amidative β-Scission of Alcohols Enabled by Dual Catalysis of Photoredox Proton-Coupled Electron Transfer and Inner-Sphere Ni-Nitrenoid Transfer

The photoredox/Ni dual catalysis is an appealing strategy to enable unconventional C-heteroatom bond formation. While significant advances have been achieved using this system, intermolecular C(sp3)-N bond formation has been relatively underdeveloped due to the difficulty in C(sp3)-N reductive elimination. Herein, we present a new mechanistic approach that utilizes dioxazolones as the Ni(II)-nitrenoid precursor to capture carbon-centered radicals by merging proton-coupled electron transfer (PCET) with nickel catalysis, thus forming synthetically versatile N-alkyl amides using alcohols. Based on mechanistic investigations, the involvement of (κ2-N,O)Ni(II)-nitrenoid species was proposed to capture photoredox PCET-induced alkyl radicals, thereby playing a pivotal role to enable the C(sp3)-N bond formation.

Photoinduced Difunctionalization of Diazenes Enabled by N-N Radical Coupling

In this study, a metal-free difunctionalization strategy for diazenes was developed using a range of bifunctionalization reagents. This strategy involves a unique N(sp3)-N(sp2) radical coupling between the hydrazine radical and the imine radical. More than 30 triazane core motifs were constructed by installing imines and various functional groups, including alkyl, phenyl, cyanoalkyl, and sulfonyl groups, on both ends of the nitrogen-nitrogen bond of diazenes in an efficient manner.

Iron Photoredox Catalysis-Past, Present, and Future

Photoredox catalysis of organic reactions driven by iron has attracted substantial attention throughout recent years, due to potential environmental and economic benefits. In this Perspective, three major strategies were identified that have been employed to date to achieve reactivities comparable to the successful noble metal photoredox catalysis: (1) Direct replacement of a noble metal center by iron in archetypal polypyridyl complexes, resulting in a metal-centered photofunctional state. (2) In situ generation of photoactive complexes by substrate coordination where the reactions are driven via intramolecular electron transfer involving charge-transfer states, for example, through visible-light-induced homolysis. (3) Improving the excited-state lifetimes and redox potentials of the charge-transfer states of iron complexes through new ligand design. We seek to give an overview and evaluation of recent developments in this rapidly growing field and, at the same time, provide an outlook on the future of iron-based photoredox catalysis.

Decarboxylative sulfoximination of benzoic acids enabled by photoinduced ligand-to-copper charge transfer

Sulfoximines are synthetically important scaffolds and serve important roles in drug discovery. Currently, there is no solution to decarboxylative sulfoximination of benzoic acids; although thoroughly investigated, limited substrate scope and harsh reaction conditions still hold back traditional thermal aromatic decarboxylative functionalization. Herein, we realize the first decarboxylative sulfoximination of benzoic acids via photo-induced ligand to copper charge transfer (copper-LMCT)-enabled decarboxylative carbometalation. The transformation proceeds under mild reaction conditions, has a broad substrate scope, and can be applied to late-stage functionalization of complex small molecules.

Iron/Photosensitizer Hybrid System Enables the Synthesis of Polyaryl-Substituted Azafluoranthenes

Photosensitization of organometallics is a privileged strategy that enables challenging transformations in transition-metal catalysis. However, the usefulness of such photocatalyst-induced energy transfer has remained opaque in iron-catalyzed reactions despite the intriguing prospects of iron catalysis in synthetic chemistry. Herein, we demonstrate the use of iron/photosensitizer-cocatalyzed cycloaddition to synthesize polyarylpyridines and azafluoranthenes, which have been scarcely accessible using the established iron-catalyzed protocols. Mechanistic studies indicate that triplet energy transfer from the photocatalyst to a ferracyclic intermediate facilitates the thermally demanding nitrile insertion and accounts for the distinct reactivity of the hybrid system. This study thus provides the first demonstration of the role of photosensitization in overcoming the limitations of iron catalysis.

Iron-catalyzed deconstructive alkylation through chlorine radical induced C-C single bond cleavage under visible light

Selective C-C single bond cleavage of simple compounds is a highly challenging and desired process. Herein, a chlorine radical-induced deconstructive C-C bond alkylation with alcohols and alkenes catalyzed by iron salts was reported for the first time. Readily available alcohols and various electron-deficient alkenes were tolerated. Late-stage and large-scale reactions proceed smoothly. This catalyst system shows potential for diversified deconstructive functionalization of simple C-C bonds.

Visible-Light-Induced Decarboxylative Fluorination of Aliphatic Carboxylic Acids Catalyzed by Iron

An efficient and inexpensive protocol for the direct decarboxylative fluorination of aliphatic carboxylic acids catalyzed with iron salts under visible light is presented. This new method allows the facile fluorination of a diverse array of carboxylic acids even on gram scale using a Schlenk flask without loss of efficiency. Mechanistic studies suggest that the photoinduced ligand-to-metal charge transfer process enables the generation of the key step to generate the carboxyl radical intermediates.

Electrophotochemical Ce-Catalyzed Ring-Opening Functionalization of Cycloalkanols under Redox-Neutral Conditions: Scope and Mechanism

Selective cleavage and functionalization of C-C bonds in alcohols is gaining increasing interest in organic synthesis and biomass conversion. In particular, the development of redox-neutral catalytic methods with cheap catalysts and clean energy is of utmost interest. In this work, we report a versatile redox-neutral method for the ring-opening functionalization of cycloalkanols by electrophotochemical (EPC) cerium (Ce) catalysis. The EPC-Ce-enabled catalysis allows for cycloalkanols with different ring sizes to be cleaved while tolerating a broad range of functional groups. Notably, in the presence of chloride as a counteranion and electrolyte, this protocol selectively leads to the formation of C-CN, C-C, C-S, or C-oxime bonds instead of a C-halide bond after β-scission. A preliminary mechanistic investigation indicates that the redox-active Ce catalyst can be tuned by electro-oxidation and photo-reduction, thus avoiding the use of an external oxidant. Spectroscopic characterizations (cyclic voltammetry, UV-vis, electron paramagnetic resonance, and X-ray absorption fine structure) suggest a Ce(III)/Ce(IV) catalytic pathway for this transformation, in which a Ce(IV)-alkoxide is involved.

Photoinduced Fe-Catalyzed Bromination and Iodination of Unstrained Cyclic Alcohols

We report a photoinduced iron catalysis for the efficient C─C bond cleavage and bromination or iodination of unstrained tertiary cycloalkanols with NBS/NIS. The reaction features good functional group tolerance and...

Hypervalent-iodine promoted selective cleavage of C(sp3)–C(sp3) bonds in ethers

A visible-light-promoted and radical-mediated strategy for the site-specific cleavage of C(sp3)–C(sp3) bonds in ethers is reported.