How Can Ethyl Alcohol Be Converted To Tert-pentyl Alcohol? How Can Methyl Propanoate Be Converted To Propanoic Acid? How Can Ethyl Methanoate Be Converted To Methanol? How Can Propene Be Converted To Acetaldehyde? How Can Benzyl Alcohol Be Converted To Benzophenone? How Can Benzaldehyde Be Converted To Phenylacetic Acid?

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This comprehensive guide explores the fascinating realm of organic chemistry, focusing on organic compound conversions. We will delve into a series of transformations, providing detailed procedures and explanations for each. Our focus is on understanding the underlying chemical principles that govern these reactions, ensuring a strong foundation for tackling similar challenges in organic synthesis. We will explore each conversion step-by-step, highlighting the reagents, conditions, and mechanisms involved. Whether you are a student, researcher, or simply an enthusiast of chemistry, this guide aims to enhance your knowledge and appreciation for the art of organic transformations. We aim to break down complex chemical reactions into manageable steps. By understanding the core principles of organic chemistry, such as nucleophilic substitution, addition reactions, and oxidation-reduction, we can appreciate how these reactions lead to the synthesis of complex molecules. This guide provides a comprehensive overview of essential conversions, including the synthesis of alcohols, carboxylic acids, aldehydes, and ketones from various starting materials. Let us embark on this journey of chemical discovery, where we will uncover the secrets behind molecular transformations and gain a deeper understanding of the building blocks of our world.

a. Ethyl Alcohol to tert-Pentyl Alcohol

In the realm of alcohol synthesis, converting ethyl alcohol to tert-pentyl alcohol requires a multi-step process involving Grignard reagents. This conversion highlights the versatility of Grignard chemistry in building carbon-carbon bonds and creating complex alcohols. This transformation provides a fantastic example of how to use Grignard reagents in synthesis. This transformation showcases the power of Grignard reagents in organic synthesis, as they enable the formation of new carbon-carbon bonds, a crucial process in building larger and more complex molecules. The entire process involves multiple distinct reactions, each with its own reagents and conditions. Each step is crucial for achieving the desired transformation, and a deep understanding of each step is essential for success. In this section, we'll explore the individual steps, reagents, and conditions required to bring about this transformation. Understanding the mechanism of each step is crucial for understanding the overall transformation. By carefully controlling the reaction conditions, we can selectively synthesize the desired tert-pentyl alcohol. This reaction sequence demonstrates the power of organic synthesis in creating complex molecules from simpler ones. The first key step involves the transformation of ethyl alcohol into a suitable electrophile, followed by the crucial Grignard reaction that forms the desired carbon-carbon bond. Tert-pentyl alcohol, a tertiary alcohol, has unique properties and is a valuable compound in various chemical applications. This conversion is not only a testament to the power of Grignard reagents but also to the beauty and complexity of organic synthesis. Throughout this detailed explanation, we aim to empower you with a profound understanding of this transformation, equipping you with the knowledge to tackle similar synthetic challenges.

Step 1: Converting Ethyl Alcohol to Ethyl Halide

Begin by converting ethyl alcohol (CH₃CH₂OH) to an ethyl halide, such as ethyl bromide (CH₃CH₂Br). This can be achieved by reacting ethyl alcohol with phosphorus tribromide (PBr₃). The reaction is as follows:

3 CH₃CH₂OH + PBr₃ → 3 CH₃CH₂Br + H₃PO₃

This reaction proceeds via a nucleophilic substitution (SN2) mechanism, where the bromide ion acts as a nucleophile, displacing the hydroxyl group. Using PBr₃ offers a clean and efficient conversion to the alkyl halide. The reaction requires anhydrous conditions to prevent the hydrolysis of PBr₃. The product, ethyl bromide, is a crucial intermediate for the next step, the formation of the Grignard reagent. This step is vital as it transforms the alcohol into a better leaving group, facilitating the subsequent nucleophilic attack. The SN2 mechanism ensures that the stereochemistry at the carbon center is inverted, although this is not relevant in this particular reaction since ethyl alcohol is achiral. The yield of this reaction is typically high, making it a reliable method for generating ethyl bromide. By controlling the reaction temperature and using appropriate stoichiometry, the formation of unwanted byproducts can be minimized. This step is a cornerstone in the overall synthesis, highlighting the importance of converting functional groups to enable further reactions. The conversion of ethyl alcohol to ethyl bromide is an essential step, laying the groundwork for the creation of a Grignard reagent, a key player in carbon-carbon bond formation.

Step 2: Formation of Grignard Reagent

Next, prepare the Grignard reagent by reacting ethyl bromide with magnesium turnings in anhydrous diethyl ether (Et₂O).

CH₃CH₂Br + Mg → CH₃CH₂MgBr

The Grignard reagent, ethylmagnesium bromide (CH₃CH₂MgBr), is a powerful nucleophile. The reaction must be carried out under anhydrous conditions, as Grignard reagents react violently with water. Diethyl ether acts as a solvent and helps stabilize the Grignard reagent. The reaction proceeds via a radical mechanism, with the magnesium metal inserting itself between the carbon and bromine atoms. The formation of the Grignard reagent is an example of an organometallic reaction, where a carbon-metal bond is formed. This newly formed carbon-magnesium bond is highly polar, making the carbon atom strongly nucleophilic. The Grignard reagent is a versatile reagent in organic synthesis, capable of reacting with a wide variety of electrophiles. The success of the Grignard reaction is critically dependent on the purity of the reagents and the absence of moisture. A slow addition of ethyl bromide to the magnesium turnings in ether helps control the reaction. This step is a crucial turning point in the synthesis, as it generates the nucleophile needed to build the carbon skeleton of the target molecule. The Grignard reagent acts as a carbanion equivalent, a carbon atom carrying a partial negative charge, making it an excellent nucleophile for carbon-carbon bond formation.

Step 3: Reaction with a Ketone

Now, react the Grignard reagent with a suitable ketone to introduce the tert-pentyl skeleton. Diethyl ketone (CH₃CH₂COCH₂CH₃) is the ketone of choice. The reaction proceeds as follows:

CH₃CH₂MgBr + CH₃CH₂COCH₂CH₃ → CH₃CH₂C(OMgBr)(CH₂CH₃)₂

The Grignard reagent attacks the carbonyl carbon of the ketone, forming a new carbon-carbon bond. The carbonyl carbon is electrophilic due to the electron-withdrawing nature of the oxygen atom. This addition reaction forms a magnesium alkoxide intermediate. The reaction is typically carried out at low temperatures to control the exothermicity. The choice of diethyl ketone is strategic, as it provides the necessary carbon framework for the target molecule, tert-pentyl alcohol. This step is the key carbon-carbon bond-forming step in the synthesis. The nucleophilic attack of the Grignard reagent on the carbonyl group is a fundamental reaction in organic chemistry. The reaction is highly regioselective, with the Grignard reagent attacking the carbonyl carbon exclusively. This step showcases the power of Grignard reactions in building complex molecules from simpler building blocks. The alkoxide intermediate is unstable and requires further processing to yield the final alcohol product.

Step 4: Hydrolysis to Form tert-Pentyl Alcohol

Finally, hydrolyze the magnesium alkoxide intermediate with dilute acid (e.g., HCl) to obtain tert-pentyl alcohol:

CH₃CH₂C(OMgBr)(CH₂CH₃)₂ + H₂O + H⁺ → (CH₃CH₂)₂C(OH)CH₂CH₃ + MgBr(OH)

The acid hydrolysis protonates the alkoxide, leading to the formation of the alcohol. The magnesium salts are converted to soluble forms and removed in the aqueous phase. This step is crucial for liberating the alcohol from the magnesium complex. The hydrolysis reaction is typically rapid and exothermic. The resulting tert-pentyl alcohol is a tertiary alcohol, characterized by the presence of a hydroxyl group attached to a carbon atom bonded to three other carbon atoms. The acid used for hydrolysis should be dilute to prevent unwanted side reactions. The workup typically involves separating the organic layer containing the tert-pentyl alcohol from the aqueous layer containing the magnesium salts. Further purification, such as distillation, may be required to obtain pure tert-pentyl alcohol. This final step completes the conversion of ethyl alcohol to tert-pentyl alcohol, demonstrating the power of Grignard chemistry in organic synthesis. The successful execution of this hydrolysis step is the culmination of the entire synthetic sequence, yielding the desired target molecule.

b. Methyl Propanoate to Propanoic Acid

The conversion of methyl propanoate to propanoic acid involves the hydrolysis of an ester. This transformation highlights the fundamental relationship between esters and carboxylic acids, showcasing how simple chemical reactions can convert one functional group into another. The hydrolysis of an ester is a classic reaction in organic chemistry, demonstrating the reactivity of esters in the presence of water and a catalyst. This conversion provides a clear example of how to break an ester bond and form a carboxylic acid. The entire process is driven by the nucleophilic attack of water on the carbonyl carbon of the ester, followed by proton transfer steps. This transformation is not only important in synthesis but also in understanding the breakdown of esters in biological systems. In this section, we will explore the mechanism, conditions, and reagents required for this conversion. Understanding the mechanism is key to predicting the outcome of the reaction and optimizing the reaction conditions. By carefully controlling the pH and temperature, we can achieve a high yield of propanoic acid. This reaction demonstrates the importance of functional group interconversion in organic chemistry. The hydrolysis of esters is a reversible reaction, but under the right conditions, it can be driven to completion, favoring the formation of the carboxylic acid. Propanoic acid, a short-chain fatty acid, has numerous applications in various industries, making this conversion industrially relevant. Through this detailed explanation, we aim to provide you with a comprehensive understanding of ester hydrolysis and its application in converting methyl propanoate to propanoic acid.

Hydrolysis of Ester

Methyl propanoate (CH₃CH₂COOCH₃) can be converted to propanoic acid (CH₃CH₂COOH) by hydrolysis. This can be achieved by either acid or base hydrolysis.

Acid Hydrolysis

React methyl propanoate with water in the presence of an acid catalyst, such as hydrochloric acid (HCl) or sulfuric acid (H₂SO₄). The reaction is as follows:

CH₃CH₂COOCH₃ + H₂O + H⁺ ⇌ CH₃CH₂COOH + CH₃OH

This reaction is an equilibrium reaction, meaning it can proceed in both directions. The acid catalyst protonates the carbonyl oxygen, making the carbonyl carbon more electrophilic and susceptible to nucleophilic attack by water. The water molecule acts as a nucleophile, attacking the carbonyl carbon and forming a tetrahedral intermediate. The intermediate then undergoes proton transfer steps, leading to the elimination of methanol and the formation of propanoic acid. The reaction is typically carried out at elevated temperatures to increase the rate of hydrolysis. An excess of water is often used to drive the equilibrium towards the product side. The reaction is reversible, and the yield can be improved by removing either the methanol or the propanoic acid as they are formed. This method provides a direct route to propanoic acid, utilizing water as the nucleophile in the presence of an acid catalyst. The acid hydrolysis of esters is a widely used method in organic chemistry, applicable to a wide range of esters. The mechanism is well-understood and involves several protonation and deprotonation steps. This reaction underscores the dynamic equilibrium between esters and carboxylic acids in aqueous solutions. The protonation of the carbonyl oxygen is a key step in activating the ester towards nucleophilic attack.

Base Hydrolysis (Saponification)

Alternatively, methyl propanoate can be hydrolyzed using a base, such as sodium hydroxide (NaOH) or potassium hydroxide (KOH). This process is also known as saponification. The reaction is as follows:

CH₃CH₂COOCH₃ + NaOH → CH₃CH₂COONa + CH₃OH CH₃CH₂COONa + HCl → CH₃CH₂COOH + NaCl

In the first step, the hydroxide ion (OH⁻) acts as a strong nucleophile, attacking the carbonyl carbon of the ester. This forms a tetrahedral intermediate, which collapses to eliminate the methoxide ion (CH₃O⁻). The product of this step is the sodium salt of propanoic acid. This step is irreversible due to the formation of the carboxylate anion, which is resonance stabilized. To obtain the free propanoic acid, the carboxylate salt is then treated with a strong acid, such as hydrochloric acid (HCl). The acid protonates the carboxylate anion, forming propanoic acid. This method is generally faster than acid hydrolysis because the hydroxide ion is a stronger nucleophile than water. The reaction is irreversible under basic conditions, driving the reaction to completion. Saponification is commonly used to hydrolyze triglycerides into glycerol and fatty acid salts, which are used to make soap. The reaction is typically carried out in a water-alcohol mixture to ensure the solubility of both the ester and the base. The base hydrolysis of esters provides an efficient route to carboxylic acids, particularly when combined with acidification to generate the free acid. The formation of the carboxylate salt in the first step makes this reaction effectively irreversible, driving the equilibrium towards the products. This method is widely used in both laboratory and industrial settings for ester hydrolysis.

c. Ethyl Methanoate to Methanol

The reduction of ethyl methanoate to methanol is a transformation that highlights the reduction of esters to alcohols. This conversion demonstrates the use of powerful reducing agents in organic synthesis. The reduction of an ester to an alcohol is a fundamental reaction in organic chemistry, allowing for the creation of primary alcohols from ester starting materials. This conversion provides a clear example of how to use reducing agents like lithium aluminum hydride (LiAlH₄) or sodium borohydride (NaBH₄) in synthesis. The entire process involves the nucleophilic attack of the hydride ion on the carbonyl carbon of the ester, followed by subsequent proton transfer steps. This transformation is crucial in various synthetic schemes, enabling the creation of alcohols from readily available esters. In this section, we'll explore the mechanism, conditions, and reagents necessary for this reduction. Understanding the mechanism is essential for predicting the outcome and optimizing the reaction. By carefully choosing the reducing agent and controlling the conditions, we can achieve a high yield of methanol. This reaction illustrates the power of reduction reactions in organic synthesis, enabling the transformation of functional groups to lower oxidation states. The choice of reducing agent depends on the reactivity of the ester and the desired selectivity of the reduction. Methanol, a simple alcohol, is a valuable solvent and a precursor to many other chemical compounds, making this conversion industrially significant. Through this detailed explanation, we aim to equip you with a comprehensive understanding of ester reduction and its application in converting ethyl methanoate to methanol.

Reduction with LiAlH₄

Ethyl methanoate (HCOOCH₂CH₃) can be reduced to methanol (CH₃OH) using lithium aluminum hydride (LiAlH₄), a strong reducing agent. The reaction proceeds as follows:

  1. HCOOCH₂CH₃ + LiAlH₄ → [Intermediate]
  2. [Intermediate] + H₂O → CH₃OH + CH₃CH₂OH

LiAlH₄ is a powerful reducing agent that can reduce esters to primary alcohols. The reaction involves the nucleophilic attack of the hydride ion (H⁻) from LiAlH₄ on the carbonyl carbon of ethyl methanoate. This forms an unstable tetrahedral intermediate. The intermediate then collapses, eliminating ethoxide (CH₃CH₂O⁻) as a leaving group and forming an aldehyde. The aldehyde is further reduced by LiAlH₄ to the corresponding alcohol. The final step involves the hydrolysis of the aluminum alkoxide with water to yield methanol and ethanol. LiAlH₄ is a strong reducing agent and must be used in anhydrous conditions as it reacts violently with water. The reaction is typically carried out in an aprotic solvent, such as diethyl ether or tetrahydrofuran (THF). The reduction of ethyl methanoate with LiAlH₄ results in the formation of two alcohols: methanol (from the carbonyl group) and ethanol (from the ethoxy group). This method provides a highly effective way to reduce esters to alcohols, although the strong reducing power of LiAlH₄ requires careful handling. The hydride ion acts as a nucleophile, attacking the carbonyl carbon and initiating the reduction process. The formation of the aldehyde intermediate is followed by rapid reduction to the alcohol, ensuring a high yield of the primary alcohol. This method showcases the versatility of LiAlH₄ in organic synthesis, allowing for the efficient reduction of a wide range of carbonyl compounds.

Reduction with NaBH₄ (Alternative, but less effective)

Sodium borohydride (NaBH₄) is a milder reducing agent and is generally not effective for reducing esters directly. However, it can reduce the aldehyde intermediate formed during the reaction if specific conditions are used. While NaBH₄ is less reactive than LiAlH₄, it is safer to handle and can be used in protic solvents such as ethanol or methanol. In this case, if the reaction is carried out in two steps where the ester is first hydrolyzed to the acid and then reacted with NaBH₄, the aldehyde formed as intermediate during hydrolysis gets reduced to alcohol. Overall, for direct reduction of esters, LiAlH₄ remains the reagent of choice due to its higher reducing power.

d. Propene to Acetaldehyde

The conversion of propene to acetaldehyde is an oxidation reaction that can be achieved through various methods, including the Wacker process. This transformation is a key example of how alkenes can be converted to carbonyl compounds, expanding the repertoire of organic synthesis. The oxidation of propene to acetaldehyde is an industrially important process, highlighting the practical applications of organic transformations. This conversion provides a clear example of how to use transition metal catalysis to achieve selective oxidation of alkenes. The Wacker process, a cornerstone of industrial chemistry, involves the use of a palladium catalyst to oxidize alkenes to aldehydes or ketones. In this section, we will explore the mechanism, conditions, and reagents involved in this conversion. Understanding the mechanism is crucial for understanding the regioselectivity and stereoselectivity of the reaction. By carefully controlling the reaction conditions, we can achieve a high yield of acetaldehyde, minimizing the formation of side products. This reaction demonstrates the power of transition metal catalysis in organic synthesis, enabling the selective oxidation of alkenes under mild conditions. Acetaldehyde, a versatile chemical intermediate, is used in the production of various industrial chemicals, making this conversion economically significant. Through this detailed explanation, we aim to provide you with a comprehensive understanding of the Wacker process and its application in converting propene to acetaldehyde.

Wacker Process

The most common method for converting propene (CH₃CH=CH₂) to acetaldehyde (CH₃CHO) is the Wacker process, which uses a palladium catalyst. The overall reaction is:

2 CH₃CH=CH₂ + O₂ → 2 CH₃CHO

The Wacker process involves the oxidation of an alkene using a palladium(II) catalyst, typically palladium(II) chloride (PdCl₂), and a copper(II) chloride (CuCl₂) co-catalyst in an aqueous solution. The mechanism begins with the coordination of propene to the palladium(II) center. A water molecule then attacks the coordinated alkene, followed by a series of proton transfers to form a hydroxyalkylpalladium intermediate. This intermediate undergoes a β-hydride elimination to form acetaldehyde and a palladium hydride species. The palladium hydride is then oxidized back to palladium(II) by CuCl₂, which itself is reoxidized by oxygen. The CuCl₂ acts as a reoxidant, preventing the palladium catalyst from being reduced to palladium(0), which is inactive. The Wacker process is an example of homogeneous catalysis, where the catalyst and reactants are in the same phase. The reaction is typically carried out in water as the solvent. The Wacker process is widely used in the chemical industry for the production of aldehydes and ketones from alkenes. The selectivity of the reaction can be influenced by the choice of substituents on the alkene. The Wacker process is a powerful example of how transition metal catalysis can be used to achieve selective oxidation reactions. The reaction is environmentally friendly, as it uses oxygen as the oxidant and generates water as a byproduct. This method provides an efficient and selective route for converting propene to acetaldehyde, highlighting the versatility of transition metal catalysis in organic synthesis.

e. Benzyl Alcohol to Benzophenone

The conversion of benzyl alcohol to benzophenone is an oxidation reaction, transforming a primary alcohol into a ketone. This conversion highlights the use of oxidizing agents in organic chemistry and demonstrates the importance of controlling the oxidation state of organic compounds. This transformation exemplifies the selective oxidation of a primary alcohol to a ketone, a crucial reaction in organic synthesis. This conversion provides a clear example of how to use oxidizing agents like pyridinium chlorochromate (PCC) or Swern oxidation conditions to achieve this transformation. The entire process involves the removal of hydrogen atoms from the alcohol, resulting in the formation of a carbonyl group. Benzophenone, a diaryl ketone, is a valuable compound in various chemical applications, making this conversion industrially relevant. In this section, we will explore the mechanisms, conditions, and reagents required for this oxidation. Understanding the mechanism is essential for predicting the outcome and optimizing the reaction conditions. By carefully choosing the oxidizing agent and controlling the stoichiometry, we can achieve a high yield of benzophenone, minimizing the formation of over-oxidation products. This reaction demonstrates the power of oxidation reactions in organic synthesis, enabling the transformation of alcohols to carbonyl compounds. The choice of oxidizing agent depends on the desired selectivity and the susceptibility of other functional groups in the molecule. Through this detailed explanation, we aim to provide you with a comprehensive understanding of alcohol oxidation and its application in converting benzyl alcohol to benzophenone.

Oxidation with PCC

Benzyl alcohol (C₆H₅CH₂OH) can be oxidized to benzophenone (C₆H₅COC₆H₅) using pyridinium chlorochromate (PCC), a mild oxidizing agent. The reaction proceeds as follows:

C₆H₅CH₂OH + PCC → C₆H₅CHO C₆H₅CHO + PCC → C₆H₅COC₆H₅

PCC is a reagent used for oxidizing primary alcohols to aldehydes and secondary alcohols to ketones. However, in this case, we need a stronger oxidizing agent or conditions to further oxidize the aldehyde (benzaldehyde) to a ketone (benzophenone). The first step of the reaction involves the formation of benzaldehyde. To further oxidize benzaldehyde to benzophenone, we need more vigorous conditions or a different oxidizing agent. However, using PCC alone might not be sufficient for this two-step oxidation. So, the direct conversion of benzyl alcohol to benzophenone using only PCC is not efficient. Alternative oxidation methods, such as Swern oxidation or using stronger oxidizing agents, are generally preferred for this conversion.

Swern Oxidation (Preferred Method)

A more efficient method for oxidizing benzyl alcohol to benzophenone is the Swern oxidation. This method involves the use of dimethyl sulfoxide (DMSO), oxalyl chloride, and a base, such as triethylamine. The reaction proceeds as follows:

  1. (CH₃)₂SO + (COCl)₂ → [Activated DMSO]
  2. C₆H₅CH₂OH + [Activated DMSO] → [Alkoxysulfonium Ion]
  3. [Alkoxysulfonium Ion] + Et₃N → C₆H₅CHO + (CH₃)₂S
  4. C₆H₅CHO (further oxidized via similar mechanism) → C₆H₅COC₆H₅

The Swern oxidation is a mild and versatile method for oxidizing alcohols to aldehydes and ketones. The first step involves the activation of DMSO by oxalyl chloride at low temperatures (-78°C). The activated DMSO species then reacts with benzyl alcohol to form an alkoxysulfonium ion intermediate. The addition of a base, such as triethylamine, deprotonates the alkoxysulfonium ion, leading to the formation of benzaldehyde and dimethyl sulfide. If we need benzophenone as the final product, benzaldehyde undergoes further oxidation via a similar mechanism to yield benzophenone. The Swern oxidation is an example of a sulfonium-based oxidation, where DMSO acts as the source of oxygen. The reaction is typically carried out in dichloromethane (CH₂Cl₂) as the solvent. The Swern oxidation is widely used in organic synthesis due to its mild conditions and high yields. The reaction is particularly useful for oxidizing alcohols that are sensitive to strong oxidizing agents. This method provides an efficient and selective route for converting benzyl alcohol to benzophenone, highlighting the versatility of oxidation reactions in organic chemistry.

f. Benzaldehyde to Phenylacetic Acid

The conversion of benzaldehyde to phenylacetic acid involves the Baeyer-Villiger oxidation followed by hydrolysis. This transformation is a powerful method for converting aldehydes to carboxylic acids with the insertion of an oxygen atom. This conversion provides a clear example of how to use peroxyacids, such as meta-chloroperoxybenzoic acid (mCPBA), in the Baeyer-Villiger oxidation. The entire process involves the nucleophilic attack of the peroxyacid on the carbonyl carbon, followed by rearrangement and hydrolysis. Phenylacetic acid, an aryl-substituted acetic acid, has numerous applications in various chemical industries, making this conversion industrially relevant. In this section, we will explore the mechanisms, conditions, and reagents required for this conversion. Understanding the mechanism is essential for predicting the outcome and optimizing the reaction conditions. By carefully controlling the stoichiometry and temperature, we can achieve a high yield of phenylacetic acid, minimizing the formation of side products. This reaction demonstrates the power of oxidation reactions in organic synthesis, enabling the transformation of aldehydes to carboxylic acids with unique selectivity. The Baeyer-Villiger oxidation is particularly useful for converting cyclic ketones to lactones and aldehydes to esters or carboxylic acids. Through this detailed explanation, we aim to provide you with a comprehensive understanding of the Baeyer-Villiger oxidation and its application in converting benzaldehyde to phenylacetic acid.

Baeyer-Villiger Oxidation

The Baeyer-Villiger oxidation involves the reaction of an aldehyde or ketone with a peroxyacid to form an ester or a lactone. In the case of benzaldehyde (C₆H₅CHO), the reaction with a peroxyacid, such as meta-chloroperoxybenzoic acid (mCPBA), followed by hydrolysis will yield phenylacetic acid (C₆H₅CH₂COOH). The reaction proceeds as follows:

  1. C₆H₅CHO + mCPBA → [Baeyer-Villiger intermediate]
  2. [Baeyer-Villiger intermediate] + H₂O → C₆H₅CH₂COOH

The mechanism of the Baeyer-Villiger oxidation begins with the nucleophilic attack of the peroxyacid on the carbonyl carbon of benzaldehyde. This forms a Criegee intermediate. The Criegee intermediate then undergoes a rearrangement, where a group migrates from the carbonyl carbon to the oxygen atom of the peroxyacid. In the case of benzaldehyde, a phenyl group migration is favored if we want to form a phenol ester, but a hydride shift leads to phenyl formate. A subsequent hydrolysis step is needed to convert phenyl formate to phenylacetic acid. Instead, we can consider an alternative pathway where the Baeyer-Villiger oxidation is followed by a Wittig reaction followed by hydrogenation to achieve the desired product more efficiently. However, to provide a more direct and accurate transformation, a modified Baeyer-Villiger approach is more appropriate.

Modified Baeyer-Villiger with Wittig and Hydrogenation (Alternative Route for Clarity)

Given the typical Baeyer-Villiger oxidation may not directly yield phenylacetic acid efficiently from benzaldehyde due to the formation of phenyl formate, a more directed synthetic route is considered for clarity:

  1. Wittig Reaction: Benzaldehyde reacts with a Wittig reagent to form an α,β-unsaturated ester or alkene. C₆H₅CHO + Ph₃P=CHCOOR → C₆H₅CH=CHCOOR

  2. Hydrogenation: The resulting unsaturated ester or alkene is hydrogenated to form the saturated ester. C₆H₅CH=CHCOOR + H₂ → C₆H₅CH₂CH₂COOR

  3. Hydrolysis: The ester is hydrolyzed to phenylacetic acid. C₆H₅CH₂CH₂COOR + H₂O → C₆H₅CH₂CH₂COOH + ROH

This approach ensures a controlled and efficient conversion of benzaldehyde to phenylacetic acid. While the initial assessment considered a Baeyer-Villiger oxidation followed by hydrolysis, a more deliberate approach involving Wittig olefination, hydrogenation, and ester hydrolysis is presented for improved synthetic clarity. This multi-step transformation provides a strategic way to transform benzaldehyde to phenylacetic acid, ensuring greater control over the reaction outcome.