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Organi II Mechanisms

Date post: 18-Dec-2015
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mecanismos em química orgânica
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Organic II Mechanisms 1. Alkadienes a. HX addition to a conjugated diene: b. General Diels-alder cycloaddition reaction(Diene must be in cis configuration): 2. Aromatics a. Electrophilic aromatic substitution (halogenation): b. Electrophilic aromatic substitution (Nitration): c. Electrophilic aromatic substitution (Sulfonation):
Transcript
  • Organic II Mechanisms 1. Alkadienes a. HX addition to a conjugated diene:

    b. General Diels-alder cycloaddition reaction(Diene must be in cis configuration):

    2. Aromatics a. Electrophilic aromatic substitution (halogenation):

    b. Electrophilic aromatic substitution (Nitration):

    c. Electrophilic aromatic substitution (Sulfonation):

  • d. Electrophilic aromatic substitution (Alkylation):

    e. Electrophilic aromatic substitution (Acylation):

    f. Nucleophilic substitution reaction of aryl halides with EWG (Meisenheimer complex; ortho/para only):

    g. Preparation of phenol from halobenzene via benzyne:

  • 3. Alcohols a. 3o alcohol- acid catalyzed dehydration:

    b. 2o, 3o alcohol dehydration with POCl3:

    c. 3o alcohol to alkyl halide using HX (X= Cl, Br, I):

    d. 1o, 2o alcohol to alkyl halide using SOCl2:

    e. 1o, 2o alcohol to alkyl halide using PBr3:

  • 4. Ethers a. Acid catalyzed synthesis of symmetrical ethers (1o alcohols only):

    b. Williamson ether synthesis (1o or 2o RX only; can be intramolecular):

    c. Alkoxymercuration of alkene to form ethers:

    d. Acidic cleavage of ethers(1o and 2o ethers; HI or HBr only):

    e. Claisen rearrangement of an allyl aryl:

    f. Alkenes with peroxyacid:

  • g. Alkene with X2/H2O and a strong base:

    h. Acid-catalyzed epoxide ring opening(X=F, Br, Cl or I):

    i. Base-catalyzed epoxide ring opening (Sn2) :

    5. Aldehydes/Ketones a. Nucleophilic addition to a ketone or aldehyde:

    b. Grignard(RMgX) addition to a ketone or aldehyde:

    c. Hydride addition to a ketone or aldehyde:

  • d. 1o amine addition to a ketone or aldehyde (Imine formation):

    e. 2o amine addition to a ketone or aldehyde (Enamine formation):

    f. Wittig Reaction:

    g. Conjugate addition of a nucleophile to an ,-unsaturated aldehyde or ketone:

    Nu=RNH2, R2NH, R2CuLi(R:-), -:CN

    enolate

  • 6. Carboxylic Acids/Nitriles a. Carboxylation of Grignard reagent to prepare carboxylic acids:

    b. Nitrile with an organometallic reagent:

    7. Carboxylic Acid Derivatives a. Conversion of carboxylic acid into acid chloride:

    b. Conversion of carboxylic acid into acid anhydride:

    c. Conversion of carboxylic acid into an ester ( 2 ways):

    Sn2 Route

    Fischer esterification

  • d. Conversion of carboxylic acid halides into carboxylic acids, esters, amides, aldehydes, ketones, or alcohols: (Y= Cl, Br)

    e. Conversion of carboxylic acid anhydrides into carboxylic acids, esters, amides, or alcohols: (Y= O2CR)

    f. Conversion of esters into carboxylic acids, amides, or alcohols: (Y= OR)

    g. Conversion of amides into carboxylic acids: (Y= NH2, NHR, NR2)

  • 8. Carbonyl -Substitutions a. Base catalyzed enolate formation:

    b. Acid catalyzed enol formation:

    c. -halogenation of a carbonyl (aldehydes/ketones only):

    d. Hell-Vollhard-Zelinski (HVZ) reaction (carboxylic acids only):

    e. Haloform reaction (methyl ketones only):

  • f. Alkylation of enolates, esters and ketones (Sn2 reactions):

    g. alkylation of nitriles:

    h. Malonic ester synthesis:

    i. Acetoacetic ester synthesis:

  • 9. Carbonyl Condensations a. General carbonyl condensation reaction:

    b. Base catalyzed dehydration of an aldol:

    c. Acid catalyzed dehydration of an aldol:

    d. Intramolecular aldol condensation reaction:

    e. Claisen condensation reaction:

  • f. Dieckmann cyclization (intramolecular Claisen condensation):

    g. Michael addition reactions:

    h. Stork enamine reaction:

    Reverse of enamine formation yields:

  • i. Robinson annulation reaction (Combination of Michael rxn 1st, followed by an intramolecular Aldol rxn):

    See intramolecular aldol rxn above for the mechanism of part 2.

    10. Amines a. Azide synthesis of a primary amine:

  • b. Gabriel synthesis of an amine:

    c. Reductive amination of aldehydes and ketones:


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