Technical articles
Experimental Selection Logic for Transition-Metal-Catalyzed C–H Functionalization: When It Is Worth Pursuing and How to Assess Site Selectivity and Conditions
Experimental Selection Logic for Transition-Metal-Catalyzed C–H Functionalization: When It Is Worth Pursuing and How to Assess Site Selectivity and Conditions
This article focuses on carbon-hydrogen (C–H) functionalization within the framework of transition-metal catalysis, and does not cover other types of C–H transformations such as radical, photoredox, or electrochemical processes. The central questions addressed here are: how to judge whether this route is worth pursuing, how selectivity can be achieved at the target site, which type of transformation corresponds to the desired product, how the sequence of condition screening should be arranged, and when it is more appropriate to revert to a prefunctionalization-based route.
The core value of transition-metal-catalyzed C–H functionalization lies in directly converting a C–H bond in a molecule into a carbon-carbon, carbon-nitrogen, carbon-oxygen, or carbon-halogen bond, thereby reducing the need for additional precursor preparation and bringing positions that are otherwise difficult to manipulate directly into the synthetic route. However, it is not the default first-choice strategy, because site selectivity, directing-group burden, the oxidation system, and substrate compatibility still often determine success or failure.
1. When to Give Priority to Transition-Metal-Catalyzed C–H Functionalization
Before screening specific methods, first determine whether this route is worth adopting. The key question is not simply whether C–H functionalization can be done, but whether direct modification at this site offers a shorter sequence, lower sample consumption, and a better fit with the structural features of the current substrate than a route that first prepares cross-coupling precursors such as halides or boronates and then converts them. When the goal is late-stage modification of complex molecules, local scaffold fine-tuning, or access to a target site that is not easily reached through conventional prefunctionalization, transition-metal-catalyzed C–H functionalization is often worth considering first. If the target precursor is itself easy to prepare, or if the reaction requires additional installation and removal of a directing group, the step economy of this route is often diminished.
Situation | Cases in Which Transition-Metal-Catalyzed C–H Functionalization Can Be Prioritized | Cases in Which Transition-Metal-Catalyzed C–H Functionalization Should Not Be Prioritized |
Target site | Conventional precursors are difficult to access, or the molecule already contains inherent positional bias | Precursors such as halides or boronates are readily available |
Stage of the molecule | The synthesis is already at a late stage and rebuilding the scaffold is undesirable | The synthesis is still at an early scaffold-construction stage, so route modification is low-cost |
Experimental objective | Late-stage modification, rapid analogue expansion, local scaffold fine-tuning | The task is simply to carry out a well-established coupling, and the conventional route is shorter |
Step burden | No additional installation and removal of auxiliary structures is required | A directing group must be installed and then removed in separate steps |
Process requirements | Small-scale screening and structural diversification are the main priorities | Scale-up, cost reduction, and simpler workup are the main priorities |
2. Screening Priorities for Different Substrate Types
Different substrate types require different screening priorities. In transition-metal-catalyzed C–H functionalization, arenes, heteroarenes, aliphatic sites, and late-stage modification of complex molecules often correspond to different modes of site control, common side reactions, and sequences of condition screening. Therefore, initial screening should first be organized according to substrate type: is selectivity at the target site mainly controlled by a directing group, or by electronic effects, steric differentiation, or pre-existing functional groups within the molecule? This step is especially important for aliphatic C(sp3)–H bonds. Compared with aromatic or vinylic C(sp2)–H bonds, aliphatic C(sp3)–H bonds are generally more difficult to functionalize regioselectively because there are often more competing sites and conformational effects are more pronounced. As a result, useful selectivity often has to be established through directing groups, auxiliary ligands, or specially designed reaction modes.
Substrate type | Method entry point to examine first | Common sources of site control | What to check first at the start of screening | Common challenges |
Arenes | Directed systems or nondirected arene functionalization | Directing groups, steric effects, electronic effects, ligand control | Whether ortho direction is feasible; in nondirected cases, whether steric differentiation is sufficient | Competition among multiple sites; over-functionalization |
Heteroarenes | Direct arylation, borylation, amination, oxidation, etc. | Intrinsic electronic distribution of the ring, heteroatom coordination, steric effects | Whether the heteroatom assists site control or instead causes catalyst deactivation | Strong coordination suppresses catalysis; regioselectivity shifts |
Aliphatic C(sp3)–H sites | Directed proximal functionalization, transient directing strategies, or systems controlled by specialized ligands | Directing groups, conformational constraints, ligand control | Which site can form a stable metallacycle, and whether the substrate can tolerate the conditions | Small differences among sites, low conversion, numerous side reactions |
Late-stage modification of complex molecules | Late-stage functionalization systems under mild conditions | Existing functional groups within the molecule, local steric and electronic differences | Which position is most likely to undergo single-site modification without damaging the remaining functional groups | Poor functional-group compatibility, precious sample, narrow reaction window |
For arene systems, the first question is often whether a usable directing group is present. If the substrate contains coordinating functional groups such as amides, pyridines, quinolines, or imines, ortho-selective or other proximal directed systems are usually examined first. If the substrate lacks a clear directing element, the next question is whether steric and electronic effects are sufficient to support a nondirected transformation. For heteroarenes, it is necessary to judge additionally whether the heteroatom in the ring helps control the site of reaction or instead coordinates too strongly to the metal and deactivates the catalyst.
Condition screening for aliphatic C(sp3)–H sites cannot simply follow the logic used for arene systems. The first step is to determine whether the target site can form a viable activation pathway through a directing group, conformational constraint, or neighboring functional group, and only then to fine-tune the catalyst, ligand, and reaction conditions. For late-stage modification of complex molecules, the first priorities are whether substrate quantity is limited, whether other functional groups in the molecule can tolerate the reaction conditions, and whether the reaction must occur exclusively at the target site. In such projects, the primary objective is usually not the highest yield, but rather a modification result with usable chemoselectivity and site selectivity on limited material.
3. How Selectivity Is Achieved at the Target Site
In transition-metal-catalyzed C–H functionalization, site selectivity usually arises from four types of factors: (1) proximal selectivity generated through coordination of a directing group; (2) transient direction or reversible in situ coordination; (3) the substrate’s own electronic effects and steric differentiation; and (4) inherent positional bias provided by pre-existing functional groups in complex molecules. One should first determine whether selectivity at the target site mainly derives from a directing group, from the substrate’s intrinsic electronic and steric features, or from selectivity shaped by the ligand and catalytic system; on this basis, the metal, ligand, and oxidation system can then be selected.
Source of site selectivity | Applicable situations | Key point to assess |
Directing-group coordination | The substrate already contains a coordinating functional group | Whether the directing ability is sufficient, and whether the geometry supports activation at the target site |
Transient directing strategy | The substrate has no fixed directing group, but can form a reversible coordinating species in situ | Whether in situ formation is sufficiently stable, and whether it introduces additional side reactions |
Electronic effects and steric differentiation | Arenes or heteroarenes lacking a clear directing group | Whether the steric and electronic differences are sufficient to provide usable selectivity |
Inherent positional bias within the molecule | Complex molecules or drug-like molecules | Which position is most likely to undergo single-site modification while preserving the main scaffold |
If the origin of site selectivity itself cannot be clearly defined, then simply changing the metal, increasing the temperature, or switching the solvent will usually not solve the underlying problem. In most failed cases, the issue is not that the catalyst is “not powerful enough,” but that the target site never had a reliable basis for selectivity in the first place.
4. The Desired Product Determines Which Type of C–H Transformation to Examine First
Once the site has been identified, the next step is to determine which type of C–H transformation is needed to reach the desired product. In practice, three broad situations are common. One is to convert the target site first into an intermediate that can be further derivatized, for example through C–H borylation. Another is to convert the target site directly into a new carbon-carbon bond for scaffold editing or fragment introduction. A third is to install nitrogen-, oxygen-, or halogen-containing functionality at the target site in order to adjust polarity, reactivity, or the scope for subsequent transformations.
Experimental objective | Reaction class to screen first | Main use |
Install a handle first, then transform further | C–H borylation | Convert an inert site into a derivatizable handle for downstream transformations |
Direct scaffold modification | Arylation, alkenylation, alkylation | Direct formation of a new carbon-carbon bond |
Introduce heteroatoms or adjust polarity | Amination, oxidation, hydroxylation, halogenation | Direct installation of nitrogen-, oxygen-, or halogen-containing functionality |
Generate a series of analogues or perform late-stage modification of complex molecules | Choose specific transformations such as borylation, arylation, alkenylation, amination, oxidation, or halogenation according to the target functionality | Rapidly compare how changes in substituents affect properties |
C–H borylation is often prioritized as a “handle-installation” entry point because the resulting organoboron intermediates can subsequently be converted into alcohols, amines, aryl groups, or halides. For simple nondirected arenes, regiocontrol in iridium-catalyzed C–H borylation is usually dominated by steric factors; for heteroarenes or substrates bearing substituents capable of interacting with the catalytic system, steric and electronic effects often jointly influence regioselectivity. If the goal is direct scaffold modification, arylation, alkenylation, and alkylation are more closely aligned with the task itself. If the goal is to adjust polarity, alter hydrogen-bonding capacity, or leave a functional handle for downstream derivatization, amination, hydroxylation, and halogenation are more direct choices.
5. The Order of Condition Screening in Transition-Metal-Catalyzed C–H Functionalization
For condition screening in transition-metal-catalyzed C–H functionalization, the reaction framework should be established first, and the specific parameters fine-tuned afterward. A commonly used sequence is as follows: first determine whether reliable site selectivity can be established at the target position; then determine which class of C–H transformation is involved and which catalytic mode corresponds to it; next screen ligands, additives, and the oxidation system; and finally adjust solvent, concentration, temperature, and order of addition. The reason for arranging the process in this way is that site control and catalytic mode determine whether the reaction is viable at all. If these two aspects have not been established, simply expanding the catalyst or condition matrix often only increases unproductive screening.
Order | Question to answer first |
Step 1 | Why should the target site be selected? |
Step 2 | What type of bond is being formed in this transformation? |
Step 3 | Which catalytic mode matches the metal system? |
Step 4 | How should the ligand, additives, and oxidation system be combined? |
Step 5 | How should solvent, concentration, temperature, and order of addition be adjusted? |
Ligands, additives, and the oxidation system should not be treated as background conditions. In many systems, what truly determines conversion, regioselectivity, and whether overreaction occurs is the ligand environment, acid-base additives, silver salts, or other oxidants, rather than the metal precursor itself. Once the site-selection logic and reaction class are in place, further adjustment of solvent, concentration, temperature, and order of addition usually makes it easier to obtain reproducible results. In nondirected systems, heteroarene systems, or systems that depend heavily on a particular ligand and additive environment, the metal, ligand, additives, and solvent often also need to be screened in parallel, rather than being optimized strictly along a single sequential path.
6. Common Failure Modes and Directions for Adjustment
When an experiment fails, the most common outcomes can generally be grouped into five categories: scrambled site selectivity, low conversion, overreaction, substrate decomposition, and cases that work on small scale but perform poorly upon scale-up. When such problems arise, it is usually more effective to identify the problem type first from the observed experimental outcome, and then separately examine site control, the catalytic system, the oxidation conditions, and substrate tolerance in order to define an adjustment strategy.
Experimental observation | Common cause | Direction for adjustment |
Multiple sites react simultaneously | Site differentiation is too small, directing effect is insufficient, ligand is mismatched | Strengthen the site-controlling element, switch to a directed system, or revert to a prefunctionalization route |
Conversion is very low | The target site itself is unreactive, the substrate strongly coordinates and deactivates the catalyst, or the coupling partner/oxidation system is mismatched | Change the reaction class first, then adjust the metal and additives |
Over-functionalization | The product is more reactive than the starting material, or the oxidation conditions are too strong | Limit the extent of reaction, weaken the oxidation conditions, and modify the mode of addition |
Clear substrate decomposition | The substrate contains acid-sensitive, oxidation-sensitive, reduction-sensitive, or strongly coordinating sites | Switch to a milder system, and if necessary abandon this type of route |
Performance deteriorates upon scale-up | Problems associated with precious metals, silver salts, oxidants, and heat/mass transfer become amplified | Assess process burden early and do not directly extrapolate small-scale results |
The situation that most needs to be recognized early is when the underlying site-selection logic is not valid. If multiple similar sites are present, if the substrate contains strongly coordinating heteroatoms, or if the directing group itself requires two extra steps to remove, continued fine-tuning within the same method family will often only consume more sample.
7. When to Switch Back to a Route Based on Preparing a Precursor First and Transforming It Thereafter
Transition-metal-catalyzed C–H functionalization is generally suitable for late-stage fine-tuning of complex molecules, for handling sites whose conventional precursors are difficult to access directly, and for projects that require rapid generation of a series of analogues. If precursors corresponding to the target site, such as halides or boronates that can undergo further transformation, are already easy to prepare, or if additional installation and removal of a directing group is required in order to achieve C–H functionalization, then the step advantage of this route is often weakened. For projects in which scale-up, cost, and simplification of workup are major priorities, it is also necessary to assess the practical limitations associated with precious metals, external oxidants, and directing-group burden.
Scenario | Recommendation |
Local late-stage modification of complex molecules | Give priority to C–H functionalization |
Rapid generation of a series of analogues | Give priority to C–H functionalization |
The target site is difficult to access directly through conventional precursors | Give priority to C–H functionalization |
Precursors corresponding to the target site, such as halides or boronates, are readily available | A route based on preparing the precursor first and then transforming it may be considered first |
Installation and removal of the directing group introduces extra steps | A route based on preparing the precursor first and then transforming it may be considered first |
The substrate shows poor tolerance toward the metal or oxidation system | A route based on preparing the precursor first and then transforming it may be considered first |
The project is focused on scale-up, cost reduction, and simpler workup | A route based on preparing the precursor first and then transforming it should usually be evaluated first |
When conventional precursors to the target site are already easy to access, or when C–H functionalization requires additional investment in directing-group manipulations and condition screening, a route based on preparing a precursor first and then transforming it is often easier to implement.
8. Navigation Table of Representative Chemicals Related to Transition-Metal-Catalyzed C–H Functionalization (Choose Table 1–Table 4 by Research or Experimental Objective)
Research or experimental objective | Recommended table to consult first | Why start with this table | Suggested related table(s) to consult | Navigation notes |
You have already decided to carry out directed aromatic C–H functionalization and are selecting among palladium, rhodium, and ruthenium catalytic systems | Table 1 | Table 1 concentrates palladium, rhodium, and ruthenium catalysts and precatalysts, making it easier to establish an initial screening plan according to the metal system and reaction type | Tables 3 and 4 | First determine the metal system according to substrate type and target transformation, then refine the conditions in combination with the directing group and oxidation system |
You already have coordinating substrates such as amides, oximes, or heterocycles, and want to judge whether the directing group is sufficient or whether the directing design should be changed | Table 3 | Table 3 concentrates classical bidentate directing groups, transient directing group precursors, and commonly used auxiliary ligands, making it easier to judge the origin of site control | Tables 1 and 4 | First determine which directing mode the site selectivity depends on, then return to the corresponding metal system and oxidation conditions for combined screening |
The substrate does not contain a pre-existing strong directing group, and you want to try transient direction or auxiliary-ligand-assisted C–H activation | Table 3 | Table 3 corresponds to transient direction, weak-coordination assistance, and carboxylate-assisted activation pathways | Tables 1 and 4 | First evaluate whether reversible direction or assisted activation can be established, then decide whether to proceed to screening in palladium, ruthenium, or related systems |
The research focus is arene or heteroarene C–H borylation, and you want to establish a borylation entry first | Table 2 | Table 2 concentrates commonly used precatalysts, nitrogen ligands, and boron sources for iridium-catalyzed borylation, making it easier to set up the borylation system first | Use with Table 4 if needed | First identify the iridium source, ligand, and boron source in Table 2, then decide according to substrate reactivity whether oxidation or auxiliary systems also need to be consulted |
You want to convert an inert site first into an organoboron intermediate that can be further derivatized, and then carry out subsequent coupling or oxidation transformations | Table 2 | Table 2 directly serves the experimental route of “install a handle first, then transform further” | Table 1 | First establish the borylation entry, then decide according to the downstream objective whether to move into other transition-metal-catalyzed transformations |
You already have a preliminary result with a metal system, but the conversion is low and you want to adjust reactivity through a ligand or additive | Table 3 | Bipyridines, phenanthrolines, picolinic acid, and carboxylic acid additives in Table 3 often affect activation efficiency and site selectivity | Tables 1 and 4 | First determine whether the problem lies in site control or insufficient reactivity, then decide whether to adjust the ligand, the catalyst, or the oxidation system |
The reaction requires an external reoxidant, or you suspect that the oxidation system is affecting yield and side reactions | Table 4 | Table 4 concentrates persulfates, peroxides, hypervalent iodine reagents, silver salts, and copper salts, making it easier to compare different oxidation modes | Table 1 | First determine which type of oxidative transformation the reaction belongs to, then match the reoxidant, additives, and corresponding metal precatalyst |
You are using a halide-ligated metal precatalyst and want to judge whether silver-salt activation is needed | Table 4 | Silver acetate and silver carbonate in Table 4 directly correspond to halide removal and metal activation requirements | Table 1 | First check the structure of the metal precatalyst, then determine whether silver salts are needed for activation and reoxidation |
You are conducting oxidative C–H functionalization, cross-dehydrogenative coupling, or cyclization, and want to compare oxidant routes | Table 4 | Table 4 covers common strong oxidants, mild oxidative auxiliaries, and hypervalent iodine systems, making it easier to screen according to reaction strength and side-reaction risk | Tables 1 and 3 | First choose the oxidation mode according to the reaction type, then adjust the metal system and directing mode together |
The substrate is structurally complex and sample amount is limited, and you want to establish a reliable screening sequence first | Table 3 | For complex substrates, site control must be addressed first; Table 3 is more suitable for first judging directing, transient direction, and auxiliary-ligand pathways | Tables 1 and 4 | First confirm the source of site control, then proceed to screen the metal system and oxidation conditions to reduce ineffective combinations |
There are multiple similar sites on the same substrate and you are concerned about site scrambling | Table 3 | Site scrambling primarily involves the directing mode, auxiliary ligands, and carboxylate-assisted cleavage pathways | Table 1 | First determine whether directing-group design can widen the difference among sites, then return to the specific metal system for validation |
You want to reproduce a literature procedure, but are unsure whether to check the catalyst, ligand, or oxidant first | Consult Table 1 first, then Table 3, and finally Table 4 | The metal precatalyst determines the reaction type, the ligand and directing system determine site control, and the oxidant and additives determine whether the catalytic cycle can be closed | Consult Table 2 additionally if needed | For reproduction, first verify the metal source, then the ligand and directing conditions, and finally the oxidant and auxiliary systems such as silver and copper salts |
Table 1 | Palladium, Rhodium, and Ruthenium Catalysts and Precatalysts
Classification | CAS No. | Aladdin Catalog No. | Name | Specification or Purity | Product features and applications |
Palladium precatalyst | 3375-31-3 | Palladium(II) acetate (47% Pd) | Suitable for synthesis | A commonly used palladium source for condition screening in directed C–H arylation, alkenylation, acetoxylation, and oxidative coupling of substrates such as aromatic amides, oximes, and heterocycles | |
Rhodium precatalyst | 12354-85-7 | C431633 | Chiralyst P618 | Umicore | Commonly used as a rhodium(III) precatalyst for condition screening in directed C–H alkenylation, acylation, arylation, and cyclization of aromatic amides, heterocycles, and oxime ether substrates |
Palladium precatalyst | 106224-36-6 | Palladium pivalate | ≥99.95% metals basis | A palladium source bearing a carboxylate ligand, often used together with carboxylic acid additives in carboxylate-assisted C–H cleavage, and suitable for screening arylation, alkenylation, and alkylation at difficult-to-activate sites | |
Ruthenium precatalyst | 15243-33-1 | Triruthenium dodecacarbonyl | ≥99.95% metals basis | A zero-valent ruthenium precatalyst commonly used for condition screening in directed aromatic C–H activation, cyclization, and carbonyl-involved transformations | |
Ruthenium precatalyst | 25360-32-1 | Carbonyldihydridotris(triphenylphosphine)ruthenium(II) | ≥99% | A ruthenium hydride precatalyst that can be used to explore conditions for ruthenium-catalyzed directed olefin insertion, alkenylation, and dehydrogenative C–H transformations | |
Ruthenium precatalyst | 13815-94-6 | Ruthenium(III) chloride trihydrate | ≥98.0% | A commonly used ruthenium source that can generate active ruthenium species in situ, serving screening in oxidative C–H functionalization, dehydrogenative coupling, and late-stage modification | |
Palladium precatalyst | 42196-31-6 | Palladium(II) trifluoroacetate | ≥98% | A relatively electrophilic palladium source commonly used for condition screening in oxidative C–H acetoxylation, alkoxylation, amination, and halogenation | |
Ruthenium precatalyst | 52462-29-0 | Dichloro(p-cymene)ruthenium dimer | ≥97%(T) | A commonly used Ru(II) precatalyst for directed C–H arylation, alkenylation, acylation, and cyclization of substrates such as amides, ketoximes, and heterocycles |
Table 2 | Catalysts, Ligands, and Boron Sources Related to Iridium-Catalyzed C–H Borylation
Classification | CAS No. | Aladdin Catalog No. | Name | Specification or Purity | Product features and applications |
Nitrogen-containing bidentate ligand | 366-18-7 | 2,2'-Bipyridyl | AR, ≥99% | A classical nitrogen-containing bidentate ligand, commonly used together with iridium precatalysts in C–H borylation of arenes and heteroarenes, affecting both reactivity and site distribution | |
Nitrogen-containing bidentate ligand | 1660-93-1 | 3,4,7,8-Tetramethyl-1,10-phenanthroline | ≥98%(HPLC) | An electron-rich nitrogen ligand often used to increase the rate of iridium-catalyzed C–H borylation and to assist condition screening for difficult substrates | |
Nitrogen-containing bidentate ligand | 72914-19-3 | 4,4′-Di-tert-butyl-2,2′-dipyridyl | ≥98% | A sterically demanding bipyridyl ligand commonly used to tune the reactivity, regioselectivity, and substrate adaptability of iridium-catalyzed C–H borylation | |
Iridium precatalyst for borylation | 12112-67-3 | Chloro(1,5-cyclooctadiene)iridium(I) dimer | ≥97% | A commonly used iridium(I) precatalyst, employed with bipyridyl or phenanthroline ligands for condition screening in arene and heteroarene C–H borylation | |
Iridium precatalyst for borylation | 12148-71-9 | (1,5-Cyclooctadiene)(methoxy)iridium dimer | ≥96% | A relatively active iridium(I) precatalyst, often used under mild conditions to generate active iridium-boryl species in situ for C–H borylation screening | |
Diboron reagent | 73183-34-3 | Bis(pinacolato)diboron | ≥99% | A commonly used diboron reagent for generating organoboron intermediates through iridium-catalyzed C–H borylation, facilitating subsequent coupling or oxidative transformations | |
Borane reagent | 25015-63-8 | 4,4,5,5-Tetramethyl-1,3,2-dioxaborolane | ≥97% | Can serve as a monoboron source in C–H borylation and can also be used to compare how different boron sources affect reactivity and site distribution |
Table 3 | Directing Groups, Transient Directing Group Precursors, and General Auxiliary Ligands/Additives
Classification | CAS No. | Aladdin Catalog No. | Name | Specification or Purity | Product features and applications |
Nitrogen-containing bidentate ligand | 66-71-7 | 1,10-Phenanthroline | Moligand™, ≥99% | A nitrogen-containing bidentate ligand used to tune the electronic environment of the metal center, and also seen in some oxidative C–H functionalization and dehydrogenative coupling systems | |
N,O-type auxiliary ligand | 98-98-6 | 2-Picolinic acid | ≥99% | Can serve as an N,O-type auxiliary ligand to promote condition screening for certain palladium-catalyzed C(sp3)–H activation and directed functionalization | |
Carboxylic acid additive | 75-98-9 | Pivalic acid (PA) | ≥99% | A commonly used carboxylic acid additive that participates in carboxylate-assisted deprotonation and can improve the rate and conversion of aromatic C–H activation | |
Classical bidentate directing group | 1452-77-3 | Picolinamide | ≥98%(HPLC) | A classical bidentate directing group often installed on amine or acid derivatives for ortho C–H alkenylation, arylation, alkynylation, and amination | |
Classical bidentate directing group | 578-66-5 | 8-Aminoquinoline | ≥98% | A strongly coordinating bidentate directing group commonly used for ortho or β-C–H activation and functionalization of aliphatic amide or aromatic amide substrates | |
Transient directing group precursor | 36404-89-4 | 2-Hydroxynicotinaldehyde | ≥97% | A commonly used transient directing group precursor that can form an imine-type directing system in situ with amine substrates, enabling C–H activation screening without prior installation of a directing group |
Table 4 | Oxidants, Silver Salts, and Copper Salt Auxiliary Systems
Classification | CAS No. | Aladdin Catalog No. | Name | Specification or Purity | Product features and applications |
Persulfate oxidant | 7727-21-1 | Potassium persulfate | GR, ≥99.5% | A strong oxidant commonly used for condition screening in C–H functionalization, oxidative coupling, and cross-dehydrogenative coupling that require an external reoxidant | |
Copper salt auxiliary | 6046-93-1 | Copper(II) acetate monohydrate | For analysis, ACS, premium grade | Commonly used as a reoxidant, an acetate source, or an additive in palladium-catalyzed oxidative C–H functionalization and coupling reactions | |
Mild oxidative auxiliary | 106-51-4 | p-Benzoquinone | Moligand™, ≥99% | A mild oxidative auxiliary commonly used in systems such as palladium-catalyzed oxidative alkenylation that require metal reoxidation | |
Silver salt auxiliary | 534-16-7 | Silver carbonate | extent of labeling: ~50 wt. % loading | A silver salt oxidative auxiliary and halide scavenger commonly used in activation of halide-ligated metal precatalysts and screening of directed C–H functionalization | |
Silver salt auxiliary | 563-63-3 | Silver acetate | AR, ≥99.5% | A commonly used silver salt additive that can promote halide removal, metal-center activation, and subsequent reoxidation, and is seen in palladium, rhodium, and ruthenium systems | |
Peroxide oxidant | 75-91-2 | tert-Butyl hydroperoxide solution | 70% in H2O | An external oxidant commonly used for screening in transition-metal-catalyzed oxidative C–H functionalization, alkylation, and cyclization reactions | |
Hypervalent iodine oxidant | 3240-34-4 | Iodobenzene diacetate (DIB) | ≥98% | A hypervalent iodine oxidant commonly used for condition screening in palladium-catalyzed C–H acetoxylation, alkoxylation, acyloxylation, and amination |
Note: The products listed above are representative Aladdin products. For additional product specifications, search the Aladdin website using the product name, CAS number, or catalog number.
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