But, what if you have a Ph group as an substituent? that is really a wonderful article but something confuses me that what is the trend of halogens when they behave as deactivating ortho para directors which halogen is most de activating and which is least next i want to ask that which is more activating OR or OH. Your email address will not be published. We call the substituents which lead to this result “meta- directors”. [See this previous post on the mechanism of electrophilic aromatic substitution]. 5 - Understanding Periodic Trends, From Gen Chem to Org Chem, Pt. This article is quite detailed. Planning Organic Synthesis With "Reaction Maps", The 8 Types of Arrows In Organic Chemistry, Explained, The Most Annoying Exceptions in Org 1 (Part 1), The Most Annoying Exceptions in Org 1 (Part 2), Screw Organic Chemistry, I'm Just Going To Write About Cats, On Cats, Part 1: Conformations and Configurations, The Marriage May Be Bad, But the Divorce Still Costs Money. the mechanism of electrophilic aromatic substitution, factors that affect the stability of carbocations, factors which make carbocations more unstable, Understanding Ortho, Meta, and Para Directors. Do you also have a page for conversions? Thoughts? I'm going to assume that when you're talking about m-nitrotoluene, that NO2 is on the 3rd position. https://www.cambridge.org/vi/academic/subjects/chemistry/chemistry-general-interest/nitration-and-aromatic-reactivity?format=PB, Ortho-, Para- and Meta- Directors in Electrophilic Aromatic Substitution – Master Organic Chemistry | LiveNRGY. In one pattern, ortho- and para– products dominate, and the meta- product is an extremely minor byproduct. Maybe they should call them, "Formal Wins" ? The group is nitro- and not nitrobenzene in this case. Two Important Reaction Patterns: Ortho- , Para-Directors and Meta-Directors It’s one thing to learn about electrophilic aromatic substitution reactions of benzene itself.
It is even more activating when deprotonated to give O(-) . This excess In one pattern, substituents direct the reaction to give either the “ortho” (1,2) or “para” product, with a slight preference for “para” (1,4).
Electrophilic aromatic substitution is an organic reaction in which an atom that is attached to an aromatic system (usually hydrogen) is replaced by an electrophile.Some of the most important electrophilic aromatic substitutions are aromatic nitration, aromatic halogenation, aromatic sulfonation, and alkylation and acylation Friedel–Crafts reaction. I know it’s very specific, but definitely interesting how aniline (and maybe even phenol), direct meta when they are nitrated or sulfonated, mainly because the lone pair on the nitrogen of the aniline gets protonated by the H2SO4, making it a meta director. Thus these positions are deactivated Nitro group is electron withdrawing group and thus causes electron deficiency at ortho and para positrons as is clear from the resonating structures of nitro benzene.
Examples: -CF3, -NO2, -CN. Hi James, thank you for the brilliant article? You have three phenyl groups which could interfere with your desired EAS. Acid Catalysis Of Carbonyl Addition Reactions: Too Much Of A Good Thing? But once you move beyond benzene, that’s when things start getting really interesting.. Today we’ll describe the two main patterns by which substituents “direct” electrophilic aromatic substitution. Examples: -OH, -NH2, -Me, -F, -Cl, -Br, -I. Meta-directing: Substituents which draw electron density from the ortho and para positions, hence increasing reaction on the meta position. Common Mistakes with Carbonyls: Carboxylic Acids... Are Acids! Why would you choose to have trityl as a substituent?
As a result, the electron density at meta position … Examples: -OH, -NH2, -Me. 9 - Acids and Bases, From Gen Chem to Organic Chem, Pt. It might be worth going back and revisiting some of the factors that affect the stability of carbocations. Ortho/para directors or meta directors?? First: no activating groups are meta directors. The CH3 group donates electrons to the aromatic ring due to hyperconjugation. Save my name, email, and website in this browser for the next time I comment. Similarly, determine whether -CH3 is ortho-para directing or meta-directing substituent But once you move beyond benzene, that’s when things start getting really interesting. Is it considered as a alkyl group as far a being a o,p, director? Hence, NO2 is a meta-director, as we all learned 3 - Effective Nuclear Charge, From Gen Chem to Organic Chem, Pt. 10 - Hess' Law, From Gen Chem to Organic Chem, Pt. software to draw appropriate resonance structures. I understood completely what is meant by Ortho para director and deactivating group. result agrees with what you learned in organic chemistry. It’s one thing to learn about electrophilic aromatic substitution reactions of benzene itself. This is the kinda answer I was looking for . Adding meta has more valid resonance structures in this case, so the nitro group is a deactivating meta director. The nitro group strongly deactivates the benzene ring towards electrophilic substitution. This site uses Akismet to reduce spam. CH2OH is not a great example (it will easily ionize with lewis acids to form the benzyl cation) but CH2OCH3 gives a ratio of 51% ortho, 42% para, and 7% meta in nitration. Monochlorination Products Of Propane, Pentane, And Other Alkanes, Selectivity in Free Radical Reactions: Bromination vs. Chlorination, Introduction to Assigning (R) and (S): The Cahn-Ingold-Prelog Rules, Assigning Cahn-Ingold-Prelog (CIP) Priorities (2) - The Method of Dots, Types of Isomers: Constitutional Isomers, Stereoisomers, Enantiomers, and Diastereomers, Enantiomers vs Diastereomers vs The Same? Thus these positions are deactivated towards electrophilic aromatic substitution. Deactivating substituents: Reaction stops after the first substitution. Required fields are marked *. Hi there, Is -CH₂OH an Ortho Para director or Meta Director? 13 - Equilibria, From Gen Chem to Organic Chem, Part 14: Wrapup, How Concepts Build Up In Org 1 ("The Pyramid"), Review of Atomic Orbitals for Organic Chemistry. Therefore, depending on the character of the initial substituent (R), a subsequent substituent would be placed at the ortho or para position if R is an activator/halogen or at the meta position if it is a deactivator (but not a halogen). 7 - Lewis Structures, From Gen Chem to Org Chem, Pt. What factors could be in play here? in organic chemistry. Activating substituents: After the first reaction the second (and third if applicable) follow at increased speeds. Use these results to state whether -NO2 is an ortho-para directing substituent or a Why Do Organic Chemists Use Kilocalories? CH3 groups are ortho-para directing, so you could either place the 3rd group (CH3+) on position 2, 4, or 6. In the second pattern, a different family of substituents direct the reaction to give primarily the “meta” (1,3) product.
Generally electron releasing groups. I have my board exams from feb or march.
donation - conjugation, withdrawal - inductive effect. Donation or withdrawal of electrons can occur via either a conjugative or an inductive effect.
But, what if you have a Ph group as an substituent? that is really a wonderful article but something confuses me that what is the trend of halogens when they behave as deactivating ortho para directors which halogen is most de activating and which is least next i want to ask that which is more activating OR or OH. Your email address will not be published. We call the substituents which lead to this result “meta- directors”. [See this previous post on the mechanism of electrophilic aromatic substitution]. 5 - Understanding Periodic Trends, From Gen Chem to Org Chem, Pt. This article is quite detailed. Planning Organic Synthesis With "Reaction Maps", The 8 Types of Arrows In Organic Chemistry, Explained, The Most Annoying Exceptions in Org 1 (Part 1), The Most Annoying Exceptions in Org 1 (Part 2), Screw Organic Chemistry, I'm Just Going To Write About Cats, On Cats, Part 1: Conformations and Configurations, The Marriage May Be Bad, But the Divorce Still Costs Money. the mechanism of electrophilic aromatic substitution, factors that affect the stability of carbocations, factors which make carbocations more unstable, Understanding Ortho, Meta, and Para Directors. Do you also have a page for conversions? Thoughts? I'm going to assume that when you're talking about m-nitrotoluene, that NO2 is on the 3rd position. https://www.cambridge.org/vi/academic/subjects/chemistry/chemistry-general-interest/nitration-and-aromatic-reactivity?format=PB, Ortho-, Para- and Meta- Directors in Electrophilic Aromatic Substitution – Master Organic Chemistry | LiveNRGY. In one pattern, ortho- and para– products dominate, and the meta- product is an extremely minor byproduct. Maybe they should call them, "Formal Wins" ? The group is nitro- and not nitrobenzene in this case. Two Important Reaction Patterns: Ortho- , Para-Directors and Meta-Directors It’s one thing to learn about electrophilic aromatic substitution reactions of benzene itself.
It is even more activating when deprotonated to give O(-) . This excess In one pattern, substituents direct the reaction to give either the “ortho” (1,2) or “para” product, with a slight preference for “para” (1,4).
Electrophilic aromatic substitution is an organic reaction in which an atom that is attached to an aromatic system (usually hydrogen) is replaced by an electrophile.Some of the most important electrophilic aromatic substitutions are aromatic nitration, aromatic halogenation, aromatic sulfonation, and alkylation and acylation Friedel–Crafts reaction. I know it’s very specific, but definitely interesting how aniline (and maybe even phenol), direct meta when they are nitrated or sulfonated, mainly because the lone pair on the nitrogen of the aniline gets protonated by the H2SO4, making it a meta director. Thus these positions are deactivated Nitro group is electron withdrawing group and thus causes electron deficiency at ortho and para positrons as is clear from the resonating structures of nitro benzene.
Examples: -CF3, -NO2, -CN. Hi James, thank you for the brilliant article? You have three phenyl groups which could interfere with your desired EAS. Acid Catalysis Of Carbonyl Addition Reactions: Too Much Of A Good Thing? But once you move beyond benzene, that’s when things start getting really interesting.. Today we’ll describe the two main patterns by which substituents “direct” electrophilic aromatic substitution. Examples: -OH, -NH2, -Me, -F, -Cl, -Br, -I. Meta-directing: Substituents which draw electron density from the ortho and para positions, hence increasing reaction on the meta position. Common Mistakes with Carbonyls: Carboxylic Acids... Are Acids! Why would you choose to have trityl as a substituent?
As a result, the electron density at meta position … Examples: -OH, -NH2, -Me. 9 - Acids and Bases, From Gen Chem to Organic Chem, Pt. It might be worth going back and revisiting some of the factors that affect the stability of carbocations. Ortho/para directors or meta directors?? First: no activating groups are meta directors. The CH3 group donates electrons to the aromatic ring due to hyperconjugation. Save my name, email, and website in this browser for the next time I comment. Similarly, determine whether -CH3 is ortho-para directing or meta-directing substituent But once you move beyond benzene, that’s when things start getting really interesting. Is it considered as a alkyl group as far a being a o,p, director? Hence, NO2 is a meta-director, as we all learned 3 - Effective Nuclear Charge, From Gen Chem to Organic Chem, Pt. 10 - Hess' Law, From Gen Chem to Organic Chem, Pt. software to draw appropriate resonance structures. I understood completely what is meant by Ortho para director and deactivating group. result agrees with what you learned in organic chemistry. It’s one thing to learn about electrophilic aromatic substitution reactions of benzene itself. This is the kinda answer I was looking for . Adding meta has more valid resonance structures in this case, so the nitro group is a deactivating meta director. The nitro group strongly deactivates the benzene ring towards electrophilic substitution. This site uses Akismet to reduce spam. CH2OH is not a great example (it will easily ionize with lewis acids to form the benzyl cation) but CH2OCH3 gives a ratio of 51% ortho, 42% para, and 7% meta in nitration. Monochlorination Products Of Propane, Pentane, And Other Alkanes, Selectivity in Free Radical Reactions: Bromination vs. Chlorination, Introduction to Assigning (R) and (S): The Cahn-Ingold-Prelog Rules, Assigning Cahn-Ingold-Prelog (CIP) Priorities (2) - The Method of Dots, Types of Isomers: Constitutional Isomers, Stereoisomers, Enantiomers, and Diastereomers, Enantiomers vs Diastereomers vs The Same? Thus these positions are deactivated towards electrophilic aromatic substitution. Deactivating substituents: Reaction stops after the first substitution. Required fields are marked *. Hi there, Is -CH₂OH an Ortho Para director or Meta Director? 13 - Equilibria, From Gen Chem to Organic Chem, Part 14: Wrapup, How Concepts Build Up In Org 1 ("The Pyramid"), Review of Atomic Orbitals for Organic Chemistry. Therefore, depending on the character of the initial substituent (R), a subsequent substituent would be placed at the ortho or para position if R is an activator/halogen or at the meta position if it is a deactivator (but not a halogen). 7 - Lewis Structures, From Gen Chem to Org Chem, Pt. What factors could be in play here? in organic chemistry. Activating substituents: After the first reaction the second (and third if applicable) follow at increased speeds. Use these results to state whether -NO2 is an ortho-para directing substituent or a Why Do Organic Chemists Use Kilocalories? CH3 groups are ortho-para directing, so you could either place the 3rd group (CH3+) on position 2, 4, or 6. In the second pattern, a different family of substituents direct the reaction to give primarily the “meta” (1,3) product.
Generally electron releasing groups. I have my board exams from feb or march.
donation - conjugation, withdrawal - inductive effect. Donation or withdrawal of electrons can occur via either a conjugative or an inductive effect.
But, what if you have a Ph group as an substituent? that is really a wonderful article but something confuses me that what is the trend of halogens when they behave as deactivating ortho para directors which halogen is most de activating and which is least next i want to ask that which is more activating OR or OH. Your email address will not be published. We call the substituents which lead to this result “meta- directors”. [See this previous post on the mechanism of electrophilic aromatic substitution]. 5 - Understanding Periodic Trends, From Gen Chem to Org Chem, Pt. This article is quite detailed. Planning Organic Synthesis With "Reaction Maps", The 8 Types of Arrows In Organic Chemistry, Explained, The Most Annoying Exceptions in Org 1 (Part 1), The Most Annoying Exceptions in Org 1 (Part 2), Screw Organic Chemistry, I'm Just Going To Write About Cats, On Cats, Part 1: Conformations and Configurations, The Marriage May Be Bad, But the Divorce Still Costs Money. the mechanism of electrophilic aromatic substitution, factors that affect the stability of carbocations, factors which make carbocations more unstable, Understanding Ortho, Meta, and Para Directors. Do you also have a page for conversions? Thoughts? I'm going to assume that when you're talking about m-nitrotoluene, that NO2 is on the 3rd position. https://www.cambridge.org/vi/academic/subjects/chemistry/chemistry-general-interest/nitration-and-aromatic-reactivity?format=PB, Ortho-, Para- and Meta- Directors in Electrophilic Aromatic Substitution – Master Organic Chemistry | LiveNRGY. In one pattern, ortho- and para– products dominate, and the meta- product is an extremely minor byproduct. Maybe they should call them, "Formal Wins" ? The group is nitro- and not nitrobenzene in this case. Two Important Reaction Patterns: Ortho- , Para-Directors and Meta-Directors It’s one thing to learn about electrophilic aromatic substitution reactions of benzene itself.
It is even more activating when deprotonated to give O(-) . This excess In one pattern, substituents direct the reaction to give either the “ortho” (1,2) or “para” product, with a slight preference for “para” (1,4).
Electrophilic aromatic substitution is an organic reaction in which an atom that is attached to an aromatic system (usually hydrogen) is replaced by an electrophile.Some of the most important electrophilic aromatic substitutions are aromatic nitration, aromatic halogenation, aromatic sulfonation, and alkylation and acylation Friedel–Crafts reaction. I know it’s very specific, but definitely interesting how aniline (and maybe even phenol), direct meta when they are nitrated or sulfonated, mainly because the lone pair on the nitrogen of the aniline gets protonated by the H2SO4, making it a meta director. Thus these positions are deactivated Nitro group is electron withdrawing group and thus causes electron deficiency at ortho and para positrons as is clear from the resonating structures of nitro benzene.
Examples: -CF3, -NO2, -CN. Hi James, thank you for the brilliant article? You have three phenyl groups which could interfere with your desired EAS. Acid Catalysis Of Carbonyl Addition Reactions: Too Much Of A Good Thing? But once you move beyond benzene, that’s when things start getting really interesting.. Today we’ll describe the two main patterns by which substituents “direct” electrophilic aromatic substitution. Examples: -OH, -NH2, -Me, -F, -Cl, -Br, -I. Meta-directing: Substituents which draw electron density from the ortho and para positions, hence increasing reaction on the meta position. Common Mistakes with Carbonyls: Carboxylic Acids... Are Acids! Why would you choose to have trityl as a substituent?
As a result, the electron density at meta position … Examples: -OH, -NH2, -Me. 9 - Acids and Bases, From Gen Chem to Organic Chem, Pt. It might be worth going back and revisiting some of the factors that affect the stability of carbocations. Ortho/para directors or meta directors?? First: no activating groups are meta directors. The CH3 group donates electrons to the aromatic ring due to hyperconjugation. Save my name, email, and website in this browser for the next time I comment. Similarly, determine whether -CH3 is ortho-para directing or meta-directing substituent But once you move beyond benzene, that’s when things start getting really interesting. Is it considered as a alkyl group as far a being a o,p, director? Hence, NO2 is a meta-director, as we all learned 3 - Effective Nuclear Charge, From Gen Chem to Organic Chem, Pt. 10 - Hess' Law, From Gen Chem to Organic Chem, Pt. software to draw appropriate resonance structures. I understood completely what is meant by Ortho para director and deactivating group. result agrees with what you learned in organic chemistry. It’s one thing to learn about electrophilic aromatic substitution reactions of benzene itself. This is the kinda answer I was looking for . Adding meta has more valid resonance structures in this case, so the nitro group is a deactivating meta director. The nitro group strongly deactivates the benzene ring towards electrophilic substitution. This site uses Akismet to reduce spam. CH2OH is not a great example (it will easily ionize with lewis acids to form the benzyl cation) but CH2OCH3 gives a ratio of 51% ortho, 42% para, and 7% meta in nitration. Monochlorination Products Of Propane, Pentane, And Other Alkanes, Selectivity in Free Radical Reactions: Bromination vs. Chlorination, Introduction to Assigning (R) and (S): The Cahn-Ingold-Prelog Rules, Assigning Cahn-Ingold-Prelog (CIP) Priorities (2) - The Method of Dots, Types of Isomers: Constitutional Isomers, Stereoisomers, Enantiomers, and Diastereomers, Enantiomers vs Diastereomers vs The Same? Thus these positions are deactivated towards electrophilic aromatic substitution. Deactivating substituents: Reaction stops after the first substitution. Required fields are marked *. Hi there, Is -CH₂OH an Ortho Para director or Meta Director? 13 - Equilibria, From Gen Chem to Organic Chem, Part 14: Wrapup, How Concepts Build Up In Org 1 ("The Pyramid"), Review of Atomic Orbitals for Organic Chemistry. Therefore, depending on the character of the initial substituent (R), a subsequent substituent would be placed at the ortho or para position if R is an activator/halogen or at the meta position if it is a deactivator (but not a halogen). 7 - Lewis Structures, From Gen Chem to Org Chem, Pt. What factors could be in play here? in organic chemistry. Activating substituents: After the first reaction the second (and third if applicable) follow at increased speeds. Use these results to state whether -NO2 is an ortho-para directing substituent or a Why Do Organic Chemists Use Kilocalories? CH3 groups are ortho-para directing, so you could either place the 3rd group (CH3+) on position 2, 4, or 6. In the second pattern, a different family of substituents direct the reaction to give primarily the “meta” (1,3) product.
Generally electron releasing groups. I have my board exams from feb or march.
donation - conjugation, withdrawal - inductive effect. Donation or withdrawal of electrons can occur via either a conjugative or an inductive effect.
12 - Kinetics, From Gen Chem to Organic Chem, Pt. I wish I’d put that in too. Start with a monosubstituted benzene. Hence substitution occurs preferentially on those sites. Then perform some kind of electrophilic aromatic substitution (nitration, halogenation, sulfonylation – turns out it doesn’t matter). Great article! Resonating structure of nitrobenzene shows +ve charge develops in ortho and para positions.
May be I did not get the point clearly.
Since NO 2 is an electron withdrawing group, a glance at the resonance structures shows that the positive charge becomes concentrated at the ortho-para positions. Substituents which lead to this result are called, “ortho-, para- directors”.
-NO2 group is an electron withdrawing group. Notify me via e-mail if anyone answers my comment. However, the first place to start is that it has to do with the stability of the carbocation intermediate in electrophilic aromatic substitution reactions. What's The Alpha Carbon In Carbonyl Compounds? Today we’ll describe the two main patterns by which substituents “direct” electrophilic aromatic substitution.
“In the second pattern, the meta– product dominates, and the ortho- and meta– products are minor.” Just FYI, I think you meant to say “ortho- and para- products are minor” :). Aldehydes and Ketones: 14 Reactions With The Same Mechanism, Carbonyl Chemistry: 10 Key Concepts (Part 1). meta-directing substituent for electrophilic aromatic substitution.
11 - The Second Law, From Gen Chem to Org Chem Pt. Home / Ortho-, Para- and Meta- Directors in Electrophilic Aromatic Substitution, Electrophilic Aromatic Substitution – The Mechanism, Understanding Ortho, Para, and Meta Directors, Two Important Reaction Patterns: Ortho- , Para- Directors and Meta- Directors. Some Practice Problems, Antiaromatic Compounds and Antiaromaticity, The Pi Molecular Orbitals of Cyclobutadiene, Electrophilic Aromatic Substitution: Introduction, Activating and Deactivating Groups In Electrophilic Aromatic Substitution, Electrophilic Aromatic Substitution - The Mechanism, Disubstituted Benzenes: The Strongest Electron-Donor "Wins", Electrophilic Aromatic Substitutions (1) - Halogenation of Benzene, Electrophilic Aromatic Substitutions (2) - Nitration and Sulfonation, EAS Reactions (3) - Friedel-Crafts Acylation and Friedel-Crafts Alkylation, Nucleophilic Aromatic Substitution (2) - The Benzyne Mechanism, Reactions on the "Benzylic" Carbon: Bromination And Oxidation, The Wolff-Kishner, Clemmensen, And Other Carbonyl Reductions, More Reactions on the Aromatic Sidechain: Reduction of Nitro Groups and the Baeyer Villiger, Aromatic Synthesis (1) - "Order Of Operations", Synthesis of Benzene Derivatives (2) - Polarity Reversal, Aromatic Synthesis (3) - Sulfonyl Blocking Groups, Synthesis (7): Reaction Map of Benzene and Related Aromatic Compounds, Aromatic Reactions and Synthesis Practice, Electrophilic Aromatic Substitution Practice Problems.
But, what if you have a Ph group as an substituent? that is really a wonderful article but something confuses me that what is the trend of halogens when they behave as deactivating ortho para directors which halogen is most de activating and which is least next i want to ask that which is more activating OR or OH. Your email address will not be published. We call the substituents which lead to this result “meta- directors”. [See this previous post on the mechanism of electrophilic aromatic substitution]. 5 - Understanding Periodic Trends, From Gen Chem to Org Chem, Pt. This article is quite detailed. Planning Organic Synthesis With "Reaction Maps", The 8 Types of Arrows In Organic Chemistry, Explained, The Most Annoying Exceptions in Org 1 (Part 1), The Most Annoying Exceptions in Org 1 (Part 2), Screw Organic Chemistry, I'm Just Going To Write About Cats, On Cats, Part 1: Conformations and Configurations, The Marriage May Be Bad, But the Divorce Still Costs Money. the mechanism of electrophilic aromatic substitution, factors that affect the stability of carbocations, factors which make carbocations more unstable, Understanding Ortho, Meta, and Para Directors. Do you also have a page for conversions? Thoughts? I'm going to assume that when you're talking about m-nitrotoluene, that NO2 is on the 3rd position. https://www.cambridge.org/vi/academic/subjects/chemistry/chemistry-general-interest/nitration-and-aromatic-reactivity?format=PB, Ortho-, Para- and Meta- Directors in Electrophilic Aromatic Substitution – Master Organic Chemistry | LiveNRGY. In one pattern, ortho- and para– products dominate, and the meta- product is an extremely minor byproduct. Maybe they should call them, "Formal Wins" ? The group is nitro- and not nitrobenzene in this case. Two Important Reaction Patterns: Ortho- , Para-Directors and Meta-Directors It’s one thing to learn about electrophilic aromatic substitution reactions of benzene itself.
It is even more activating when deprotonated to give O(-) . This excess In one pattern, substituents direct the reaction to give either the “ortho” (1,2) or “para” product, with a slight preference for “para” (1,4).
Electrophilic aromatic substitution is an organic reaction in which an atom that is attached to an aromatic system (usually hydrogen) is replaced by an electrophile.Some of the most important electrophilic aromatic substitutions are aromatic nitration, aromatic halogenation, aromatic sulfonation, and alkylation and acylation Friedel–Crafts reaction. I know it’s very specific, but definitely interesting how aniline (and maybe even phenol), direct meta when they are nitrated or sulfonated, mainly because the lone pair on the nitrogen of the aniline gets protonated by the H2SO4, making it a meta director. Thus these positions are deactivated Nitro group is electron withdrawing group and thus causes electron deficiency at ortho and para positrons as is clear from the resonating structures of nitro benzene.
Examples: -CF3, -NO2, -CN. Hi James, thank you for the brilliant article? You have three phenyl groups which could interfere with your desired EAS. Acid Catalysis Of Carbonyl Addition Reactions: Too Much Of A Good Thing? But once you move beyond benzene, that’s when things start getting really interesting.. Today we’ll describe the two main patterns by which substituents “direct” electrophilic aromatic substitution. Examples: -OH, -NH2, -Me, -F, -Cl, -Br, -I. Meta-directing: Substituents which draw electron density from the ortho and para positions, hence increasing reaction on the meta position. Common Mistakes with Carbonyls: Carboxylic Acids... Are Acids! Why would you choose to have trityl as a substituent?
As a result, the electron density at meta position … Examples: -OH, -NH2, -Me. 9 - Acids and Bases, From Gen Chem to Organic Chem, Pt. It might be worth going back and revisiting some of the factors that affect the stability of carbocations. Ortho/para directors or meta directors?? First: no activating groups are meta directors. The CH3 group donates electrons to the aromatic ring due to hyperconjugation. Save my name, email, and website in this browser for the next time I comment. Similarly, determine whether -CH3 is ortho-para directing or meta-directing substituent But once you move beyond benzene, that’s when things start getting really interesting. Is it considered as a alkyl group as far a being a o,p, director? Hence, NO2 is a meta-director, as we all learned 3 - Effective Nuclear Charge, From Gen Chem to Organic Chem, Pt. 10 - Hess' Law, From Gen Chem to Organic Chem, Pt. software to draw appropriate resonance structures. I understood completely what is meant by Ortho para director and deactivating group. result agrees with what you learned in organic chemistry. It’s one thing to learn about electrophilic aromatic substitution reactions of benzene itself. This is the kinda answer I was looking for . Adding meta has more valid resonance structures in this case, so the nitro group is a deactivating meta director. The nitro group strongly deactivates the benzene ring towards electrophilic substitution. This site uses Akismet to reduce spam. CH2OH is not a great example (it will easily ionize with lewis acids to form the benzyl cation) but CH2OCH3 gives a ratio of 51% ortho, 42% para, and 7% meta in nitration. Monochlorination Products Of Propane, Pentane, And Other Alkanes, Selectivity in Free Radical Reactions: Bromination vs. Chlorination, Introduction to Assigning (R) and (S): The Cahn-Ingold-Prelog Rules, Assigning Cahn-Ingold-Prelog (CIP) Priorities (2) - The Method of Dots, Types of Isomers: Constitutional Isomers, Stereoisomers, Enantiomers, and Diastereomers, Enantiomers vs Diastereomers vs The Same? Thus these positions are deactivated towards electrophilic aromatic substitution. Deactivating substituents: Reaction stops after the first substitution. Required fields are marked *. Hi there, Is -CH₂OH an Ortho Para director or Meta Director? 13 - Equilibria, From Gen Chem to Organic Chem, Part 14: Wrapup, How Concepts Build Up In Org 1 ("The Pyramid"), Review of Atomic Orbitals for Organic Chemistry. Therefore, depending on the character of the initial substituent (R), a subsequent substituent would be placed at the ortho or para position if R is an activator/halogen or at the meta position if it is a deactivator (but not a halogen). 7 - Lewis Structures, From Gen Chem to Org Chem, Pt. What factors could be in play here? in organic chemistry. Activating substituents: After the first reaction the second (and third if applicable) follow at increased speeds. Use these results to state whether -NO2 is an ortho-para directing substituent or a Why Do Organic Chemists Use Kilocalories? CH3 groups are ortho-para directing, so you could either place the 3rd group (CH3+) on position 2, 4, or 6. In the second pattern, a different family of substituents direct the reaction to give primarily the “meta” (1,3) product.
Generally electron releasing groups. I have my board exams from feb or march.
donation - conjugation, withdrawal - inductive effect. Donation or withdrawal of electrons can occur via either a conjugative or an inductive effect.
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