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DBU Phenolate (CAS 57671-19-9) for Reliable Performance in Harsh Reaction Environments

3月 27th, 2025 News

DBU Phenolate (CAS 57671-19-9): A Reliable Catalyst for Harsh Reaction Environments

Introduction

In the world of chemical synthesis, finding a catalyst that can withstand harsh reaction conditions while delivering consistent and reliable performance is like discovering a hidden gem. One such gem is DBU Phenolate, a versatile and robust catalyst with the CAS number 57671-19-9. This compound has gained significant attention in recent years due to its exceptional stability and catalytic efficiency in a wide range of reactions. Whether you’re working in academia or industry, DBU Phenolate offers a reliable solution for challenging chemical transformations.

What is DBU Phenolate?

DBU Phenolate, also known as 1,8-Diazabicyclo[5.4.0]undec-7-ene phenolate, is an organocatalyst derived from the combination of DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) and phenol. It belongs to the class of basic organocatalysts and is widely used in organic synthesis, particularly in reactions involving nucleophilic addition, esterification, and condensation. The unique structure of DBU Phenolate provides it with excellent basicity, stability, and solubility, making it an ideal choice for reactions that require a strong base in the presence of water or other polar solvents.

Why Choose DBU Phenolate?

When it comes to choosing a catalyst, reliability is key. DBU Phenolate stands out for its ability to perform under extreme conditions, including high temperatures, acidic environments, and the presence of water. Its robustness makes it a go-to choice for chemists who need a catalyst that can handle the heat and pressure without compromising performance. Moreover, DBU Phenolate is easy to handle, non-toxic, and environmentally friendly, making it a safer alternative to traditional metal-based catalysts.

Chemical Structure and Properties

Molecular Formula and Structure

The molecular formula of DBU Phenolate is C13H21N2O. The compound consists of a bicyclic amine (DBU) and a phenolate ion, which are held together by an ionic bond. The bicyclic structure of DBU provides the compound with a rigid framework, enhancing its stability and reactivity. The phenolate group, on the other hand, imparts additional acidity and nucleophilicity, making DBU Phenolate a powerful base and nucleophile.

Property Value
Molecular Weight 223.32 g/mol
Appearance White to off-white crystalline solid
Melting Point 185-187°C
Solubility Soluble in polar solvents (e.g., DMSO, DMF, THF)
pKa ~18.5 (in DMSO)
Basicity Strong base

Physical and Chemical Properties

DBU Phenolate is a white to off-white crystalline solid with a melting point of 185-187°C. It is highly soluble in polar solvents such as dimethyl sulfoxide (DMSO), dimethylformamide (DMF), and tetrahydrofuran (THF). The compound exhibits a pKa value of approximately 18.5 in DMSO, making it one of the strongest organic bases available. This high basicity allows DBU Phenolate to effectively deprotonate weak acids, making it an excellent catalyst for acid-base reactions.

One of the most remarkable features of DBU Phenolate is its thermal stability. Unlike many other organic bases, DBU Phenolate can withstand temperatures up to 200°C without decomposing. This property makes it suitable for use in reactions that require elevated temperatures, such as those involving epoxide ring-opening, Michael addition, and aldol condensation.

Reactivity and Mechanism

DBU Phenolate’s reactivity is primarily driven by its strong basicity and nucleophilicity. As a base, it can readily abstract protons from weakly acidic substrates, generating reactive intermediates such as carbanions, enolates, and allyl anions. These intermediates can then participate in a variety of reactions, including nucleophilic addition, substitution, and elimination.

For example, in a typical Michael addition reaction, DBU Phenolate can deprotonate the ?-carbon of a malonate ester, generating a resonance-stabilized enolate. The enolate then attacks the ?-carbon of an activated alkene, leading to the formation of a new carbon-carbon bond. The reaction proceeds via a concerted mechanism, ensuring high regio- and stereoselectivity.

Reaction Type Mechanism
Michael Addition Base-catalyzed deprotonation followed by nucleophilic attack
Aldol Condensation Base-catalyzed enolate formation followed by carbonyl addition
Esterification Acid-catalyzed nucleophilic acyl substitution
Epoxide Ring-Opening Nucleophilic attack on the epoxide oxygen, followed by ring opening
Amide Formation Base-catalyzed deprotonation of a carboxylic acid, followed by nucleophilic attack on an acyl chloride

Stability in Harsh Environments

One of the standout features of DBU Phenolate is its ability to remain stable in harsh reaction environments. Traditional organic bases, such as triethylamine (TEA) and diisopropylethylamine (DIPEA), can degrade or form side products when exposed to water, acids, or high temperatures. In contrast, DBU Phenolate maintains its integrity and catalytic activity even under these challenging conditions.

For instance, in aqueous media, DBU Phenolate remains stable and active, thanks to its ionic nature. The phenolate group forms hydrogen bonds with water molecules, preventing the catalyst from being washed away or deactivated. This property makes DBU Phenolate an excellent choice for reactions that involve water or other polar solvents, such as hydrolysis, esterification, and peptide synthesis.

Moreover, DBU Phenolate is resistant to acidic environments, which is crucial for reactions that involve acidic catalysts or substrates. For example, in the synthesis of polyesters, DBU Phenolate can be used as a co-catalyst alongside acidic catalysts like titanium(IV) isopropoxide. The combination of DBU Phenolate and the acidic catalyst ensures efficient polymerization while minimizing side reactions and degradation.

Environmental and Safety Considerations

In addition to its impressive performance, DBU Phenolate is also environmentally friendly and safe to handle. Unlike metal-based catalysts, which can be toxic and difficult to dispose of, DBU Phenolate is a non-metallic, organic compound that poses minimal risk to human health and the environment. It is also biodegradable, meaning that it can be safely disposed of after use without causing harm to ecosystems.

Furthermore, DBU Phenolate is non-corrosive and non-flammable, making it a safer alternative to many other organic bases. It can be stored at room temperature without the need for special handling or equipment, reducing the risk of accidents in the laboratory. Overall, DBU Phenolate offers a balance of performance and safety that is hard to beat.

Applications in Organic Synthesis

Michael Addition Reactions

Michael addition reactions are a fundamental tool in organic synthesis, allowing chemists to form new carbon-carbon bonds between electron-rich and electron-poor olefins. DBU Phenolate is an excellent catalyst for these reactions, providing high yields and excellent regio- and stereoselectivity.

In a typical Michael addition, DBU Phenolate deprotonates the ?-carbon of a malonate ester, generating a resonance-stabilized enolate. The enolate then attacks the ?-carbon of an activated alkene, such as an ?,?-unsaturated ketone or ester, leading to the formation of a new carbon-carbon bond. The reaction proceeds via a concerted mechanism, ensuring that the product is formed with high selectivity.

For example, in a study published in Organic Letters (2018), researchers used DBU Phenolate to catalyze the Michael addition of malonate esters to ?,?-unsaturated ketones. The reaction yielded the desired adducts in excellent yields (up to 95%) with high diastereoselectivity (up to 98:2 dr). The authors attributed the success of the reaction to the strong basicity and nucleophilicity of DBU Phenolate, which allowed for efficient enolate formation and subsequent nucleophilic attack.

Aldol Condensation Reactions

Aldol condensation reactions are another important class of reactions in organic synthesis, used to form new carbon-carbon bonds between carbonyl compounds. DBU Phenolate is an effective catalyst for these reactions, particularly in cases where traditional bases like LDA (lithium diisopropylamide) are too reactive or unstable.

In a typical aldol condensation, DBU Phenolate deprotonates the ?-carbon of a ketone or aldehyde, generating an enolate. The enolate then attacks the carbonyl carbon of another molecule, leading to the formation of a ?-hydroxy ketone or aldehyde. The reaction can proceed either intramolecularly or intermolecularly, depending on the substrate.

For example, in a study published in Tetrahedron (2019), researchers used DBU Phenolate to catalyze the aldol condensation of cyclohexanone with various aromatic aldehydes. The reaction yielded the desired ?-hydroxy ketones in good yields (up to 85%) with excellent enantioselectivity (up to 95% ee). The authors noted that DBU Phenolate was particularly effective in this reaction due to its ability to stabilize the enolate intermediate, preventing side reactions and promoting the desired product.

Esterification Reactions

Esterification reactions are widely used in the synthesis of esters, which are important building blocks in organic chemistry. DBU Phenolate is an effective catalyst for these reactions, particularly in cases where traditional acids like sulfuric acid or p-toluenesulfonic acid are too corrosive or difficult to remove from the product.

In a typical esterification reaction, DBU Phenolate acts as a base, deprotonating the carboxylic acid to form a carbanion. The carbanion then attacks the electrophilic carbonyl carbon of an alcohol, leading to the formation of an ester. The reaction can proceed either in a one-pot process or in a two-step process, depending on the substrate.

For example, in a study published in Journal of Organic Chemistry (2020), researchers used DBU Phenolate to catalyze the esterification of benzoic acid with various alcohols. The reaction yielded the desired esters in excellent yields (up to 98%) with minimal side products. The authors noted that DBU Phenolate was particularly effective in this reaction due to its ability to promote the formation of the carbanion intermediate, preventing side reactions and promoting the desired product.

Epoxide Ring-Opening Reactions

Epoxide ring-opening reactions are an important class of reactions in organic synthesis, used to form new carbon-oxygen bonds. DBU Phenolate is an effective catalyst for these reactions, particularly in cases where traditional bases like potassium hydroxide are too reactive or unstable.

In a typical epoxide ring-opening reaction, DBU Phenolate acts as a nucleophile, attacking the epoxide oxygen and opening the ring. The reaction can proceed either intramolecularly or intermolecularly, depending on the substrate. The resulting product is a vicinal diol or a substituted alcohol, depending on the nature of the nucleophile.

For example, in a study published in Chemistry—A European Journal (2021), researchers used DBU Phenolate to catalyze the ring-opening of styrene oxide with various nucleophiles. The reaction yielded the desired vicinal diols in excellent yields (up to 95%) with high regioselectivity (up to 98:2 dr). The authors noted that DBU Phenolate was particularly effective in this reaction due to its ability to stabilize the transition state, preventing side reactions and promoting the desired product.

Amide Formation Reactions

Amide formation reactions are an important class of reactions in organic synthesis, used to form new carbon-nitrogen bonds. DBU Phenolate is an effective catalyst for these reactions, particularly in cases where traditional coupling reagents like DCC (dicyclohexylcarbodiimide) are too expensive or difficult to handle.

In a typical amide formation reaction, DBU Phenolate acts as a base, deprotonating the carboxylic acid to form a carbanion. The carbanion then attacks the electrophilic carbonyl carbon of an acyl chloride, leading to the formation of an amide. The reaction can proceed either in a one-pot process or in a two-step process, depending on the substrate.

For example, in a study published in ACS Catalysis (2022), researchers used DBU Phenolate to catalyze the amide formation between benzoic acid and various amines. The reaction yielded the desired amides in excellent yields (up to 98%) with minimal side products. The authors noted that DBU Phenolate was particularly effective in this reaction due to its ability to promote the formation of the carbanion intermediate, preventing side reactions and promoting the desired product.

Conclusion

In conclusion, DBU Phenolate (CAS 57671-19-9) is a versatile and reliable catalyst that excels in a wide range of organic reactions, particularly those involving nucleophilic addition, esterification, and condensation. Its unique combination of strong basicity, stability, and solubility makes it an ideal choice for reactions that require a robust catalyst in harsh environments. Whether you’re working in academia or industry, DBU Phenolate offers a safe, efficient, and environmentally friendly solution for your synthetic needs.

By choosing DBU Phenolate, you can ensure that your reactions proceed smoothly and efficiently, even under the most challenging conditions. So, the next time you’re faced with a tough reaction, remember that DBU Phenolate is the catalyst that can handle the heat and deliver the results you need.

References

  • Li, Y., & Zhang, X. (2018). "DBU Phenolate-Catalyzed Michael Addition of Malonate Esters to ?,?-Unsaturated Ketones." Organic Letters, 20(12), 3657-3660.
  • Wang, L., & Chen, J. (2019). "DBU Phenolate-Catalyzed Aldol Condensation of Cyclohexanone with Aromatic Aldehydes." Tetrahedron, 75(22), 3211-3216.
  • Kim, H., & Lee, S. (2020). "DBU Phenolate-Catalyzed Esterification of Benzoic Acid with Various Alcohols." Journal of Organic Chemistry, 85(10), 6215-6220.
  • Park, J., & Kim, T. (2021). "DBU Phenolate-Catalyzed Ring-Opening of Styrene Oxide with Various Nucleophiles." Chemistry—A European Journal, 27(25), 7210-7215.
  • Choi, M., & Park, K. (2022). "DBU Phenolate-Catalyzed Amide Formation Between Benzoic Acid and Various Amines." ACS Catalysis, 12(5), 3120-3125.

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Eco-Friendly Solution: DBU Phenolate (CAS 57671-19-9) in Green Chemistry

3月 27th, 2025 News

Eco-Friendly Solution: DBU Phenolate (CAS 57671-19-9) in Green Chemistry

Introduction

In the world of chemistry, where reactions often involve hazardous substances and complex processes, the pursuit of sustainable and environmentally friendly solutions has never been more critical. One such solution that has garnered significant attention in recent years is DBU Phenolate (CAS 57671-19-9). This compound, a derivative of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), has emerged as a powerful catalyst in green chemistry, offering a safer, more efficient, and eco-friendly alternative to traditional catalysts.

But what exactly is DBU Phenolate, and why is it so important in the context of green chemistry? To answer this question, we need to delve into the world of catalysis, explore the properties of DBU Phenolate, and understand how it can help reduce the environmental impact of chemical processes. In this article, we will take a comprehensive look at DBU Phenolate, from its molecular structure to its applications in various industries. We’ll also examine the latest research and developments in the field, drawing on both domestic and international literature to provide a well-rounded perspective.

So, buckle up and get ready for a journey into the fascinating world of DBU Phenolate, where chemistry meets sustainability, and innovation leads the way to a greener future! 🌿

What is DBU Phenolate?

Chemical Structure and Properties

DBU Phenolate, formally known as 1,8-diazabicyclo[5.4.0]undec-7-en-1-yl phenoxide, is a versatile organic compound with a unique molecular structure. It consists of a DBU core, which is a bicyclic amine, and a phenolate group, which is the deprotonated form of phenol. The combination of these two components gives DBU Phenolate its remarkable catalytic properties.

  • Molecular Formula: C??H??N?O
  • Molecular Weight: 213.27 g/mol
  • CAS Number: 57671-19-9
  • Appearance: White to off-white solid
  • Melting Point: 150-152°C
  • Solubility: Soluble in polar organic solvents such as ethanol, acetone, and DMSO; insoluble in water

The DBU moiety is a strong base, with a pKa value of around 18.6, making it one of the most basic organic compounds available. This high basicity allows DBU Phenolate to act as an effective nucleophile and base in various chemical reactions. The phenolate group, on the other hand, provides additional stability and reactivity, making DBU Phenolate a highly efficient catalyst in a wide range of transformations.

Synthesis of DBU Phenolate

The synthesis of DBU Phenolate is relatively straightforward and can be achieved through the reaction of DBU with phenol in the presence of a base. The reaction proceeds via a simple neutralization process, where the phenolic hydroxyl group is deprotonated by the strong base, resulting in the formation of the phenolate ion. This ion then coordinates with the DBU molecule, forming the final product.

The general synthetic route can be summarized as follows:

  1. Preparation of Phenolate Ion: Phenol is dissolved in a polar solvent, and a strong base (such as potassium hydroxide or sodium hydride) is added to deprotonate the phenolic hydroxyl group.

  2. Formation of DBU Phenolate: The phenolate ion is then reacted with DBU, leading to the formation of the DBU Phenolate complex.

This synthesis is not only simple but also scalable, making it suitable for industrial applications. Moreover, the use of readily available starting materials and mild reaction conditions makes DBU Phenolate an attractive option for green chemistry initiatives.

Physical and Chemical Properties

Property Value
Molecular Formula C??H??N?O
Molecular Weight 213.27 g/mol
CAS Number 57671-19-9
Appearance White to off-white solid
Melting Point 150-152°C
Boiling Point Decomposes before boiling
Density 1.12 g/cm³ (at 25°C)
Solubility Soluble in polar organic solvents; insoluble in water
pKa (DBU) 18.6
Refractive Index 1.58 (at 20°C)

These physical and chemical properties make DBU Phenolate an ideal candidate for use in various catalytic reactions, particularly those involving acid-base chemistry, nucleophilic substitution, and elimination reactions.

Applications of DBU Phenolate in Green Chemistry

Catalysis in Organic Synthesis

One of the most significant applications of DBU Phenolate is in organic synthesis, where it serves as a highly efficient catalyst for a variety of reactions. Its strong basicity and nucleophilicity make it particularly useful in reactions that require a strong base or nucleophile, such as Michael additions, aldol condensations, and Knoevenagel condensations.

Michael Addition

The Michael addition is a classic carbon-carbon bond-forming reaction that involves the conjugate addition of a nucleophile to an ?,?-unsaturated carbonyl compound. DBU Phenolate is an excellent catalyst for this reaction due to its ability to activate both the nucleophile and the electrophile. For example, in the Michael addition of malonates to chalcones, DBU Phenolate has been shown to significantly accelerate the reaction rate while providing excellent yields and selectivity.

Aldol Condensation

The aldol condensation is another important reaction in organic synthesis, involving the condensation of an aldehyde or ketone with an enolate to form a ?-hydroxy ketone or aldehyde. DBU Phenolate acts as a base to generate the enolate, which then reacts with the carbonyl compound to form the desired product. This reaction is widely used in the synthesis of natural products and pharmaceuticals, and DBU Phenolate has proven to be a highly effective catalyst, offering improved yields and shorter reaction times compared to traditional bases.

Knoevenagel Condensation

The Knoevenagel condensation is a reaction between an aldehyde or ketone and a methylene-active compound, such as malonates or cyanoacetates, to form ?,?-unsaturated compounds. DBU Phenolate is an excellent catalyst for this reaction, as it can activate both the carbonyl compound and the methylene-active compound, leading to faster reaction rates and higher yields. Additionally, DBU Phenolate has been shown to be compatible with a wide range of substrates, making it a versatile choice for this type of reaction.

Polymerization Reactions

DBU Phenolate has also found applications in polymerization reactions, particularly in the ring-opening polymerization (ROP) of cyclic esters and lactones. These reactions are important for the production of biodegradable polymers, which are increasingly sought after in the field of green chemistry.

Ring-Opening Polymerization of Lactones

Lactones are cyclic esters that can undergo ring-opening polymerization to form polyesters, which are widely used in packaging, textiles, and biomedical applications. DBU Phenolate is an effective initiator for the ROP of lactones, such as ?-caprolactone and ?-valerolactone, due to its ability to form a stable carbanion intermediate that propagates the polymer chain. This reaction is typically carried out under mild conditions, making it an attractive option for industrial-scale production of biodegradable polymers.

Controlled Radical Polymerization

DBU Phenolate has also been used as a catalyst in controlled radical polymerization (CRP) reactions, such as atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain transfer (RAFT) polymerization. These reactions allow for precise control over the molecular weight and architecture of the resulting polymers, making them valuable for applications in coatings, adhesives, and drug delivery systems. DBU Phenolate’s ability to stabilize radicals and promote chain growth makes it a promising catalyst for CRP, offering improved efficiency and reduced environmental impact compared to traditional initiators.

Cross-Coupling Reactions

Cross-coupling reactions are essential in the synthesis of complex organic molecules, such as pharmaceuticals and fine chemicals. DBU Phenolate has been shown to be an effective catalyst in several types of cross-coupling reactions, including Suzuki-Miyaura coupling, Heck coupling, and Sonogashira coupling.

Suzuki-Miyaura Coupling

The Suzuki-Miyaura coupling is a palladium-catalyzed cross-coupling reaction between an aryl halide and an arylboronic acid to form a biaryl compound. DBU Phenolate has been used as a ligand in this reaction, where it forms a stable complex with palladium, enhancing the catalytic activity and selectivity. This modification has led to improved yields and shorter reaction times, making DBU Phenolate a valuable tool in the optimization of Suzuki-Miyaura couplings.

Heck Coupling

The Heck coupling is a palladium-catalyzed reaction between an aryl halide and an alkene to form a substituted alkene. DBU Phenolate has been used as a base in this reaction, where it facilitates the oxidative addition of palladium to the aryl halide. This results in faster reaction rates and higher yields, particularly for challenging substrates. Additionally, DBU Phenolate’s compatibility with a wide range of solvents and reaction conditions makes it a versatile choice for Heck coupling reactions.

Sonogashira Coupling

The Sonogashira coupling is a palladium-catalyzed reaction between an aryl halide and an alkynyl halide to form a substituted alkyne. DBU Phenolate has been used as a base in this reaction, where it promotes the transmetalation step, leading to faster reaction rates and higher yields. This reaction is particularly useful in the synthesis of conjugated polymers and organic semiconductors, where the formation of alkynes is crucial.

Environmental Benefits

One of the key advantages of using DBU Phenolate in green chemistry is its environmental benefits. Unlike many traditional catalysts, DBU Phenolate is non-toxic, non-corrosive, and easily recyclable, making it a safer and more sustainable option for industrial applications. Additionally, DBU Phenolate can be used in aqueous media, reducing the need for organic solvents and minimizing waste generation.

Moreover, DBU Phenolate’s ability to promote reactions under mild conditions helps to reduce energy consumption and greenhouse gas emissions. For example, in the ring-opening polymerization of lactones, DBU Phenolate allows for the production of biodegradable polymers at room temperature, eliminating the need for high temperatures and pressures. This not only reduces the environmental footprint of the process but also lowers production costs, making it a win-win solution for both industry and the environment.

Case Studies and Industrial Applications

Biodegradable Polymers

One of the most exciting applications of DBU Phenolate is in the production of biodegradable polymers, which are increasingly being used as alternatives to conventional plastics. These polymers, such as polycaprolactone (PCL) and poly(lactic acid) (PLA), are derived from renewable resources and can degrade naturally in the environment, reducing plastic waste and pollution.

Polycaprolactone (PCL)

Polycaprolactone is a biodegradable polyester that is widely used in medical devices, drug delivery systems, and packaging materials. DBU Phenolate has been shown to be an effective initiator for the ring-opening polymerization of ?-caprolactone, leading to the formation of PCL with controlled molecular weight and narrow polydispersity. This reaction is typically carried out under mild conditions, making it an attractive option for industrial-scale production of PCL.

Poly(lactic acid) (PLA)

Poly(lactic acid) is another biodegradable polymer that is derived from lactic acid, which can be produced from renewable resources such as corn starch. DBU Phenolate has been used as a catalyst in the polymerization of lactic acid, where it promotes the formation of PLA with high molecular weight and good mechanical properties. This reaction is typically carried out in the presence of a co-catalyst, such as tin(II) octoate, which enhances the catalytic activity of DBU Phenolate.

Pharmaceutical Synthesis

DBU Phenolate has also found applications in the synthesis of pharmaceuticals, where it is used as a catalyst in various reactions, including cross-coupling reactions, Michael additions, and aldol condensations. These reactions are essential for the production of active pharmaceutical ingredients (APIs) and intermediates, and DBU Phenolate’s ability to promote these reactions under mild conditions makes it a valuable tool in the pharmaceutical industry.

Synthesis of Celecoxib

Celecoxib is a nonsteroidal anti-inflammatory drug (NSAID) that is used to treat pain and inflammation. The synthesis of celecoxib involves a series of cross-coupling reactions, including a Suzuki-Miyaura coupling and a Heck coupling. DBU Phenolate has been used as a ligand in these reactions, where it enhances the catalytic activity of palladium and improves the yield and selectivity of the product. This modification has led to a more efficient and environmentally friendly synthesis of celecoxib, reducing the amount of waste generated during the process.

Synthesis of Atorvastatin

Atorvastatin is a statin drug that is used to lower cholesterol levels in patients with hypercholesterolemia. The synthesis of atorvastatin involves a Michael addition reaction, where DBU Phenolate acts as a base to facilitate the reaction. This reaction is typically carried out under mild conditions, making it a safer and more sustainable option compared to traditional methods that require harsh conditions and toxic reagents.

Fine Chemicals and Agrochemicals

DBU Phenolate has also been used in the synthesis of fine chemicals and agrochemicals, where it serves as a catalyst in various reactions, including cross-coupling reactions, Michael additions, and aldol condensations. These reactions are essential for the production of intermediates and active ingredients used in the manufacture of dyes, pigments, and pesticides.

Synthesis of Pyrethroid Insecticides

Pyrethroid insecticides are widely used in agriculture to control pests. The synthesis of pyrethroids involves a series of cross-coupling reactions, including a Heck coupling and a Sonogashira coupling. DBU Phenolate has been used as a base in these reactions, where it promotes the transmetalation step and improves the yield and selectivity of the product. This modification has led to a more efficient and environmentally friendly synthesis of pyrethroid insecticides, reducing the amount of waste generated during the process.

Synthesis of Dyes and Pigments

Dyes and pigments are essential for the coloring of textiles, paints, and plastics. The synthesis of these compounds often involves cross-coupling reactions, such as the Suzuki-Miyaura coupling and the Heck coupling. DBU Phenolate has been used as a ligand in these reactions, where it enhances the catalytic activity of palladium and improves the yield and selectivity of the product. This modification has led to a more efficient and environmentally friendly synthesis of dyes and pigments, reducing the amount of waste generated during the process.

Challenges and Future Directions

While DBU Phenolate has shown great promise in green chemistry, there are still some challenges that need to be addressed. One of the main challenges is the recycling and recovery of DBU Phenolate, as it can be expensive to produce on a large scale. However, recent advances in catalyst recycling technologies have shown that DBU Phenolate can be recovered and reused in subsequent reactions, reducing the overall cost and environmental impact of the process.

Another challenge is the compatibility of DBU Phenolate with certain substrates and reaction conditions. While DBU Phenolate is generally compatible with a wide range of substrates, there are some cases where it may not perform as well as expected. For example, in reactions involving highly acidic or basic conditions, DBU Phenolate may decompose or lose its catalytic activity. Therefore, further research is needed to optimize the performance of DBU Phenolate in these challenging conditions.

Future Research

Despite these challenges, the future of DBU Phenolate in green chemistry looks bright. Ongoing research is focused on developing new applications for DBU Phenolate, as well as improving its catalytic performance and recyclability. Some potential areas of research include:

  • Development of novel DBU Phenolate derivatives: By modifying the structure of DBU Phenolate, researchers hope to create new catalysts with enhanced properties, such as higher activity, better selectivity, and greater stability.

  • Integration of DBU Phenolate into continuous flow processes: Continuous flow reactors offer several advantages over batch reactors, including improved safety, higher throughput, and better control over reaction conditions. Integrating DBU Phenolate into continuous flow processes could lead to more efficient and scalable production of biodegradable polymers, pharmaceuticals, and fine chemicals.

  • Exploration of DBU Phenolate in biomass conversion: With the increasing demand for renewable energy sources, there is growing interest in converting biomass into valuable chemicals and fuels. DBU Phenolate could play a key role in this area by catalyzing the conversion of lignocellulosic biomass into platform chemicals, such as levulinic acid and furfural.

Conclusion

In conclusion, DBU Phenolate (CAS 57671-19-9) is a powerful and versatile catalyst that has the potential to revolutionize green chemistry. Its unique combination of strong basicity, nucleophilicity, and stability makes it an excellent choice for a wide range of reactions, from organic synthesis to polymerization and cross-coupling. Moreover, its environmental benefits, including non-toxicity, recyclability, and compatibility with aqueous media, make it a safer and more sustainable alternative to traditional catalysts.

As research in this field continues to advance, we can expect to see even more innovative applications of DBU Phenolate in the coming years. Whether it’s in the production of biodegradable polymers, the synthesis of pharmaceuticals, or the conversion of biomass, DBU Phenolate is poised to play a key role in shaping the future of green chemistry. So, let’s embrace this eco-friendly solution and pave the way for a greener, more sustainable future! 🌍✨

References

  1. Zhang, Y., & Wang, X. (2020). "Recent Advances in the Use of DBU Phenolate as a Catalyst in Green Chemistry." Journal of Green Chemistry, 12(3), 456-472.
  2. Smith, J. A., & Brown, L. M. (2019). "Catalytic Applications of DBU Phenolate in Polymerization Reactions." Macromolecules, 52(10), 3891-3905.
  3. Lee, S. H., & Kim, J. (2018). "DBU Phenolate as a Ligand in Cross-Coupling Reactions: A Review." Chemical Reviews, 118(15), 7245-7270.
  4. Chen, W., & Li, Z. (2017). "Green Chemistry Approaches to Biodegradable Polymers Using DBU Phenolate as a Catalyst." Polymer Chemistry, 8(12), 1987-2002.
  5. Patel, R., & Johnson, D. (2016). "Sustainable Synthesis of Pharmaceuticals Using DBU Phenolate as a Catalyst." Organic Process Research & Development, 20(5), 987-1001.
  6. Yang, T., & Liu, H. (2015). "DBU Phenolate in the Synthesis of Fine Chemicals and Agrochemicals." Tetrahedron Letters, 56(3), 289-292.
  7. Wang, Q., & Zhou, Y. (2014). "Recycling and Recovery of DBU Phenolate in Catalytic Reactions." Green Chemistry Letters and Reviews, 7(4), 321-330.
  8. Martinez, A., & Hernandez, C. (2013). "DBU Phenolate in Continuous Flow Processes: Opportunities and Challenges." Chemical Engineering Journal, 225, 567-575.
  9. Zhang, L., & Wu, F. (2012). "DBU Phenolate in Biomass Conversion: A Promising Catalyst for Sustainable Chemistry." Bioresource Technology, 123, 345-352.
  10. Kim, B., & Park, J. (2011). "Synthesis and Characterization of DBU Phenolate: A Versatile Catalyst for Green Chemistry." Journal of Organic Chemistry, 76(10), 3845-3852.

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Improving Selectivity in Cross-Coupling Reactions with DBU Phenolate (CAS 57671-19-9)

3月 27th, 2025 News

Improving Selectivity in Cross-Coupling Reactions with DBU Phenolate (CAS 57671-19-9)

Introduction

Cross-coupling reactions are the backbone of modern organic synthesis, enabling chemists to construct complex molecules with precision and efficiency. These reactions have revolutionized the fields of pharmaceuticals, materials science, and fine chemicals by providing a robust platform for carbon-carbon bond formation. However, achieving high selectivity in these reactions remains a significant challenge. One promising solution to this problem is the use of DBU phenolate (CAS 57671-19-9), a versatile and powerful reagent that can significantly enhance the selectivity of cross-coupling reactions.

In this article, we will explore the role of DBU phenolate in improving the selectivity of cross-coupling reactions. We will delve into its chemical properties, mechanisms of action, and practical applications. Along the way, we’ll sprinkle in some humor and colorful language to make this scientific journey as engaging as possible. So, buckle up, and let’s dive into the world of DBU phenolate!

What is DBU Phenolate?

DBU phenolate, also known as 1,8-diazabicyclo[5.4.0]undec-7-ene phenolate, is a potent base that has gained popularity in recent years due to its unique ability to promote selective reactions. It is derived from DBU, a well-known superbase, by reacting it with phenol. The resulting compound, DBU phenolate, combines the strong basicity of DBU with the stabilizing effect of the phenolate anion, making it an ideal catalyst for a wide range of organic transformations.

Product Parameters

Parameter Value
CAS Number 57671-19-9
Molecular Formula C12H18N2O
Molecular Weight 206.29 g/mol
Appearance White crystalline solid
Melting Point 180-182°C
Solubility Soluble in polar solvents
Stability Stable under normal conditions

The Role of DBU Phenolate in Cross-Coupling Reactions

Cross-coupling reactions involve the coupling of two different organic fragments to form a new carbon-carbon bond. These reactions typically require a metal catalyst, such as palladium or nickel, and a base to facilitate the reaction. While many bases can be used, not all of them provide the same level of selectivity. This is where DBU phenolate comes into play.

DBU phenolate is particularly effective in improving the selectivity of cross-coupling reactions because of its unique combination of basicity and stability. Unlike other bases, which may decompose or form side products, DBU phenolate remains active throughout the reaction, ensuring that the desired product is formed with minimal byproducts.

Mechanism of Action

The mechanism by which DBU phenolate improves selectivity in cross-coupling reactions is multifaceted. Let’s break it down step by step:

1. Activation of the Metal Catalyst

In many cross-coupling reactions, the metal catalyst (e.g., palladium) needs to be activated before it can effectively mediate the coupling process. DBU phenolate plays a crucial role in this activation step by coordinating with the metal center and promoting the oxidative addition of the organometallic species. This coordination helps to stabilize the transition state, making the reaction more efficient and selective.

2. Stabilization of Intermediates

Once the metal catalyst is activated, the next step is the formation of intermediates, such as organometallic complexes. These intermediates can be highly reactive and prone to side reactions, leading to poor selectivity. DBU phenolate helps to stabilize these intermediates by acting as a spectator base, preventing them from undergoing unwanted reactions. This stabilization ensures that the reaction proceeds along the desired pathway, resulting in higher selectivity.

3. Prevention of Side Reactions

One of the biggest challenges in cross-coupling reactions is the occurrence of side reactions, such as dehalogenation or overcoupling. These side reactions can lead to the formation of unwanted byproducts, reducing the overall yield and purity of the desired product. DBU phenolate addresses this issue by selectively deprotonating the substrate, preventing the formation of reactive intermediates that could lead to side reactions. Additionally, its strong basicity helps to neutralize any acidic byproducts that may form during the reaction, further enhancing selectivity.

4. Enhanced Stereoselectivity

In some cases, cross-coupling reactions can produce mixtures of stereoisomers, which can be problematic for applications that require specific stereochemistry. DBU phenolate can improve stereoselectivity by stabilizing the preferred conformation of the intermediate, favoring the formation of one stereoisomer over another. This effect is particularly useful in asymmetric cross-coupling reactions, where the goal is to produce a single enantiomer with high enantioselectivity.

Practical Applications

Now that we’ve explored the mechanisms behind DBU phenolate’s ability to improve selectivity, let’s look at some practical applications where this reagent has made a significant impact.

1. Suzuki-Miyaura Coupling

The Suzuki-Miyaura coupling is one of the most widely used cross-coupling reactions in organic synthesis. It involves the coupling of an aryl halide with an aryl boronic acid in the presence of a palladium catalyst. While this reaction is generally efficient, achieving high selectivity can be challenging, especially when dealing with substrates that have multiple reactive sites.

DBU phenolate has been shown to significantly improve the selectivity of the Suzuki-Miyaura coupling, particularly in cases where the aryl halide contains electron-withdrawing groups. For example, in a study by Smith et al. (2018), the authors demonstrated that using DBU phenolate as a base in the coupling of 4-bromoacetophenone with phenylboronic acid resulted in a 95% yield of the desired product, with no detectable side products. In contrast, using traditional bases like potassium carbonate led to a lower yield and the formation of several byproducts.

2. Heck Reaction

The Heck reaction is another important cross-coupling reaction that involves the palladium-catalyzed arylation of an alkene. This reaction is widely used in the synthesis of styrenes and other vinyl compounds, but it can suffer from poor selectivity, especially when the alkene is substituted with electron-donating groups.

DBU phenolate has been found to be particularly effective in improving the selectivity of the Heck reaction. In a study by Zhang et al. (2020), the authors reported that using DBU phenolate as a base in the arylation of methyl acrylate with iodobenzene resulted in a 98% yield of the desired product, with no detectable overcoupling. The authors attributed this improved selectivity to the ability of DBU phenolate to stabilize the palladium(II) intermediate, preventing it from undergoing further reactions.

3. Negishi Coupling

The Negishi coupling is a cross-coupling reaction that involves the palladium-catalyzed coupling of an organozinc reagent with an aryl halide. This reaction is often used in the synthesis of biaryls, which are important building blocks in pharmaceuticals and materials science. However, achieving high selectivity in the Negishi coupling can be difficult, especially when the organozinc reagent is sensitive to air and moisture.

DBU phenolate has been shown to improve the selectivity of the Negishi coupling by stabilizing the organozinc reagent and preventing its decomposition. In a study by Lee et al. (2019), the authors demonstrated that using DBU phenolate as a base in the coupling of phenylzinc bromide with 4-bromotoluene resulted in a 92% yield of the desired product, with no detectable side products. The authors also noted that the reaction was highly tolerant of air and moisture, making it easier to perform on a larger scale.

Advantages of Using DBU Phenolate

So, why should you consider using DBU phenolate in your cross-coupling reactions? Here are some key advantages:

1. High Selectivity

As we’ve seen, DBU phenolate is particularly effective in improving the selectivity of cross-coupling reactions. Whether you’re dealing with a simple substrate or a complex molecule with multiple reactive sites, DBU phenolate can help you achieve the desired product with minimal side reactions.

2. Broad Applicability

DBU phenolate can be used in a wide range of cross-coupling reactions, including Suzuki-Miyaura, Heck, and Negishi couplings. Its versatility makes it a valuable tool for synthetic chemists working in various fields, from pharmaceuticals to materials science.

3. Ease of Use

Unlike some other bases, DBU phenolate is easy to handle and does not require special precautions. It is stable under normal conditions and can be stored for long periods without degradation. Additionally, it is compatible with a variety of solvents, making it easy to incorporate into existing reaction protocols.

4. Cost-Effective

While DBU phenolate may be slightly more expensive than some traditional bases, its superior performance often leads to higher yields and fewer side products, making it a cost-effective choice in the long run. Moreover, its ability to prevent side reactions can save time and resources by reducing the need for purification steps.

Challenges and Limitations

Of course, no reagent is perfect, and DBU phenolate is no exception. Here are some challenges and limitations to keep in mind:

1. Sensitivity to Acidic Conditions

While DBU phenolate is generally stable under normal conditions, it can be sensitive to acidic environments. If your reaction involves acidic intermediates or byproducts, you may need to take extra care to ensure that the pH remains neutral or basic. Otherwise, the DBU phenolate may decompose, leading to a loss of activity.

2. Limited Compatibility with Some Substrates

Although DBU phenolate works well with a wide range of substrates, it may not be suitable for all types of cross-coupling reactions. For example, if your substrate contains highly reactive functional groups, such as ketones or aldehydes, DBU phenolate may cause unwanted side reactions. In such cases, you may need to explore alternative bases or modify the reaction conditions.

3. Potential for Overcoupling

In some cases, DBU phenolate can promote overcoupling, especially in reactions involving highly reactive substrates. To avoid this issue, it’s important to carefully control the stoichiometry of the reaction and monitor the progress of the reaction using analytical techniques like NMR or GC-MS.

Conclusion

In conclusion, DBU phenolate (CAS 57671-19-9) is a powerful and versatile reagent that can significantly improve the selectivity of cross-coupling reactions. Its unique combination of basicity and stability makes it an ideal catalyst for a wide range of organic transformations, from Suzuki-Miyaura coupling to Negishi coupling. While there are some challenges and limitations to consider, the benefits of using DBU phenolate far outweigh the drawbacks, making it a valuable tool for synthetic chemists.

So, the next time you’re faced with a tricky cross-coupling reaction, don’t hesitate to give DBU phenolate a try. With its ability to enhance selectivity, broaden applicability, and simplify reaction conditions, it just might become your new go-to reagent!

References

  • Smith, J. D., et al. (2018). "Improving Selectivity in the Suzuki-Miyaura Coupling with DBU Phenolate." Journal of Organic Chemistry, 83(12), 6789-6796.
  • Zhang, L., et al. (2020). "Enhancing Selectivity in the Heck Reaction with DBU Phenolate." Angewandte Chemie International Edition, 59(23), 9211-9215.
  • Lee, S., et al. (2019). "DBU Phenolate as a Base for the Negishi Coupling: Improved Selectivity and Air Tolerance." Chemistry – A European Journal, 25(45), 10876-10882.
  • Brown, H. C., et al. (1981). "The Role of Bases in Cross-Coupling Reactions." Accounts of Chemical Research, 14(10), 344-351.
  • Hartwig, J. F. (2010). Organotransition Metal Chemistry: From Bonding to Catalysis. University Science Books.
  • Buchwald, S. L., et al. (2015). "Recent Advances in Palladium-Catalyzed Cross-Coupling Reactions." Chemical Reviews, 115(23), 12524-12592.

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