Chemical Reaction Tierlist
TLDRThe video discusses the practical utility of various reactions from introductory organic chemistry, ranking them based on their real-world applications. Reactions such as the haloform, Jones oxidation, and hydrohalogenation are deemed less useful in modern research, while others like the Diels-Alder and hydrogenation are highly valued. The video also touches on the declining use of certain reactions due to safety and efficiency concerns, highlighting the evolving nature of chemical research.
Takeaways
- 📌 The haloform reaction, used to make chloroform from acetone, is generally not preferred due to the availability of purchasing chloroform and its limited practical use.
- ⚠️ Jones oxidation is considered not ideal for regular use due to its harshness and the carcinogenic nature of chromium, but it still finds occasional use in total synthesis.
- 🚫 Hydrohalogenation of alkenes, while taught as predictable, is rarely used in practice due to the need for anhydrous conditions and the preference for more selective methods.
- 🌟 The Wolf Kishner reduction, though useful in certain cases, is niche and not frequently used due to the use of hydrazine and the development of milder variants.
- 🔄 The halohydrin reaction has limited use in total synthesis and epoxide synthesis, with other contemporary methods being more familiar and preferred.
- 💡 Diels-Alder reaction is highly useful and common, especially with activated alkenes, despite the potential for mixtures of endo and exo products.
- 🌀 Ketolysis and hydrogenation are super common reactions, used frequently for protecting ketones and aldehydes, and for the reduction of various compounds, respectively.
- 🔥 LAH (Lithium Aluminum Hydride) reductions are very common, but harsh, and not ideal for industrial processes despite their reliability in research.
- 📉 Michael additions are both biologically common and synthetically useful, with glutathione acting as a natural Michael donor in our body.
- 🧪 Rarely used reactions like oxymercuration and ozonolysis still have their historical significance and very specific, niche applications.
Q & A
What is the haloform reaction and why is it not commonly used in regular research?
-The haloform reaction is a process where a ketone is chlorinated at the alpha position three times, resulting in the formation of a carboxylic acid and a chloroform. It is not commonly used in regular research because chloroform can typically be purchased, making the reaction unnecessary for most researchers. Additionally, the reaction can result in side reactions that are undesirable.
What are the drawbacks of the Jones oxidation reaction?
-The Jones oxidation reaction, while occasionally useful, is quite harsh and utilizes chromium, which is known to be carcinogenic. These factors make it less ideal for regular use, and it is generally avoided due to the health and safety concerns associated with the use of high valent chromium salts.
Why is the hydrohalogenation of alkenes not widely practiced in the industry?
-The hydrohalogenation of alkenes is not widely practiced because it often requires anhydrous gas and can lead to mixtures. In practice, it is more common to use selective methods that are reliable, such as converting alcohols to chlorides, bromides, or iodides, rather than installing halogen groups onto alkenes.
What is the main disadvantage of the Wolf Kishner reduction?
-The main disadvantage of the Wolf Kishner reduction is that it uses hydrazine, which can be problematic. While there are variants using tosyl hydrazine that can be converted under milder conditions, the reaction is still a niche transformation and is not commonly used in day-to-day operations.
How does the Diels-Alder reaction overcome some of its limitations?
-The Diels-Alder reaction overcomes some of its limitations by using more activated alkenes, such as electron-deficient alkenes, which react better with dienes. This approach can help to avoid mixtures of endo and exo products, as well as enantiomeric mixtures, by carefully choosing starting materials that are less chiral or by using enzymes that facilitate the Diels-Alder reaction.
What is the significance of the Swern oxidation in the context of total synthesis?
-The Swern oxidation is significant in total synthesis because it is extremely reliable and works almost every time on almost every alcohol, forming dimethyl sulfide as a byproduct. It is a go-to method for converting alcohols to aldehydes and, despite forming an unpleasant byproduct, its reliability makes it a valuable tool in total synthesis.
Why has the use of Osmium Tetroxide Dihydroxylation declined?
-The use of Osmium Tetroxide Dihydroxylation has declined due to its high toxicity and cost. There are alternative methods available for performing dihydroxylation reactions that are less hazardous and more cost-effective, leading to a preference for these alternatives over the use of osmium tetroxide.
What are the main advantages of the Fischer Esterification reaction?
-The Fischer Esterification reaction is advantageous because it is a reliable and cost-effective method for synthesizing esters. It does not require the use of thionyl chloride or fancy coupling reagents, and it can be used with a variety of alcohols and carboxylic acids in the presence of an acid catalyst to produce esters.
Why is the Grignard reaction considered so useful in organic chemistry?
-The Grignard reaction is considered very useful because it allows for the formation of carbon-carbon bonds by using Grignard reagents, which are strong nucleophiles. These reagents can be halogenated to form new compounds and can react with a wide range of substrates, including ketones and aldehydes, making it a versatile tool in organic synthesis.
What is the main reason for the decreased use of the Birch reduction?
-The Birch reduction has seen a decrease in use due to its requirement of anhydrous ammonia, which can be difficult to work with, and the development of alternative methods that are more user-friendly and less prone to side reactions. Additionally, the regioselectivity of the Birch reduction can be challenging to predict, leading to a preference for other, more reliable reduction methods.
How does the Friedel-Crafts alkylation reaction compare to other alkylation methods in terms of utility?
-The Friedel-Crafts alkylation reaction, while still relevant industrially, has seen a decrease in lab-scale use due to the potential for Wagner-Mirvine rearrangement and the availability of other, more selective alkylation methods. However, it remains a useful tool in certain contexts and can provide good results when used appropriately.
Outlines
🧪 Evaluating the Utility of Organic Chemistry Reactions
The video begins with the host, identifying as a chemist, aiming to evaluate various reactions from introductory organic chemistry based on their practical utility. The video format includes a visual box where each discussed reaction is displayed. Key reactions reviewed include the haloform reaction, Jones oxidation, hydrohalogenation of alkenes, and the haloform reaction, among others. Each reaction is assessed for its utility in research and practical scenarios, with most being rated from D to F tier, indicating limited usefulness despite being commonly taught.
🔬 Practical Use of Synthetic Reactions in Organic Chemistry
Continuing from the previous segment, this part discusses reactions like ketolization, hydrogenation, and the Swern oxidation. These reactions are rated higher in utility, with some like hydrogenation and Swern oxidation receiving an A tier due to their effectiveness and reliability in organic synthesis. The segment also evaluates lesser-used methods like oxymercuration and ozonolysis, which are deemed less practical due to environmental and safety concerns, ranking them lower in utility.
🧬 Advanced Organic Reactions and Their Applications
This segment dives deeper into specialized organic reactions such as the Wittig reaction and Wagner-Meerwein rearrangement, discussing their reliability and typical use cases in synthesis. It critically analyzes the use of certain reactions in both academic and industrial settings, considering factors like yield, selectivity, and environmental impact. Reactions like the Fischer esterification and hydroboration are highlighted for their practical benefits, despite some limitations.
🔧 Reviewing Industrial and Lab-Relevant Organic Reactions
The final part of the video script reviews reactions like the Friedel-Crafts reactions, emphasizing their industrial relevance compared to their practicality in lab settings. It concludes by summarizing the discussed chemical reactions across the video, categorizing them based on their utility and environmental impact, and ends with an invitation for the audience to explore more content on the channel, promising future videos on specific topics like the Diels-Alder reaction.
Mindmap
Keywords
💡Haloform Reaction
💡Jones Oxidation
💡Hydrohalogenation of Alkenes
💡Wolff-Kishner Reduction
💡Halohydrin Reaction
💡Diels-Alder Reaction
💡Ketolysis
💡Hydrogenation
💡LAH Reduction
💡Michael Addition
💡Oxymercuration
💡Ozonolysis
Highlights
The haloform reaction is discussed, which involves chlorination of a ketone to form a carboxylic acid. It's noted that this reaction is not commonly used in regular research due to the availability of purchasing chloroform.
Jones oxidation is mentioned as occasionally useful but harsh, with high valent chromium salts being carcinogenic. It's mostly avoided now, leading to its placement in the D tier.
Hydrohalogenation of alkenes is learned in undergrad, but in practice, it's rarely used due to the need for anhydrous gas and the potential for unwanted side reactions.
Wolf Kishner reduction is a conversion of ketones to CH2 groups that can be useful, but its use is limited due to the harshness of hydrazine used in the reaction.
The halohydrin reaction has some use in total synthesis and epoxide synthesis, but it's not as commonly used due to the availability of alternative methods.
Diels-Alder reaction is confirmed as very useful, especially with more activated alkenes, despite the potential for mixtures of endo and exo products.
Ketolyzation is a common reaction for protecting ketones and aldehydes, making it a highly useful reaction to researchers, placing it in the A tier.
Hydrogenation is a straightforward and commonly used reaction, with palladium on carbon being a popular choice for the process.
LAH reductions are very common in chemistry, despite being harsh, due to their effectiveness in reducing ketones, aldehydes, etc.
Michael additions are both common in biological contexts and synthetic chemistry, making it a very useful reaction.
Oxymercuration is considered not commonly employed, despite its theoretical utility in alkene hydration.
Ozonolysis is powerful but harsh and messy, leading to its rare employment in modern times, although it has historical utility.
Swern oxidation is reliable and almost always works, despite forming dimethyl sulfide, placing it in the A tier.
PCC is still a good reaction but has fallen out of favor due to the presence of chromium, placing it in the C tier.
Osmium tetroxide dihydroxylation is very rare due to its toxicity and cost, with most reactions now using alternatives.
Wittig reaction, while not used as much as before, remains a reliable reaction when needed, despite the potential for E/Z mixtures.
Fischer esterification is a great and cheap way to make esters, making it an S-tier reaction in terms of utility.
Aldol reactions, especially asymmetric aldol reactions with proline, are very useful in organic chemistry for their ability to create stereocenters quickly.
Birch reduction is not commonly used in practice, despite its theoretical importance, placing it in the E tier.
Grignard reaction is very useful, allowing for the conversion of halogens to nucleophiles and electrophiles, making it an S-tier reaction.
Friedel-Crafts alkylation has industrial relevance, but due to potential side reactions like Wagner-Mirvine rearrangement, it's placed in the D tier.
Transcripts
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