ALKENES

Preparation:

  1. Dehydrohalogenation
    of 2º or 3º alkyl halides:
  2. Dehydration of alcohols:

Reactions:

  1. Catalytic Hydrogenation:
    (Reduction)
  2. Halogenation:
    (qualitative test)
  3. Halohydrin formation:
  4. Hydration (possible C+ rearrangement)
    or Hydration by
    Oxymercuration/Demercuration:
    (without C+ rearrangement)
  5. Hydration by
    Hydroboration/Oxidation:
    (AntiMarkovnikov product):
  6. Addition of H2SO4
    (qualitative test):
  7. Addition of Alkyl Halides:
    (Markovnikov product)
  8. Addition of HBr:
    (anitMarkovnikov product)
  9. Oxidation without Cleavage
    (Hydroxylation)
    (Baeyer’s Test):
  10. Oxidation with Cleavage

ALKYNES

Preparation:

  1. Alkene halogenation/dehydrohalogenation:
  2. Alkylation of alkynides:

Reactions:

  1. Catalytic
    Hydrogenation:
  2. Halogenation:
    (qualitative test)
  3. Hydrohalogenation:
  4. Hydration:

AROMATIC REACTIONS

Electrophilic Aromatic Substitution (EAS):

An electrophile (E+) substitutes for (replaces)
hydrogen on an aromatic ring:

  1. Bromination:
  2. Chlorination:
  3. Iodination:
  4. Nitration:
  5. Sulfonation:
  6. Friedel-Crafts Alkylation:

 The aromatic ring must be as reactive as a halobenzene. Less reactive rings do not react. Even amino-substituted aromatics don't react because the amino groups are converted to electron withdrawing groups (cationic quaternary amines) by reaction with the catalyst.

 Vinyl and aryl halides do not react.

 The alkyl halide can be methyl, ethyl, 2, or 3. Other primary alkyl halide C+'s rearrange.

 Polysubstitution produces mixed products. (The product is more reactive than the reagent.)

  1. Friedel-Crafts Acylation:

 As with F.C. Alkylation, the aromatic ring must be as reactive as a halobenzene (amino groups also fail)

 Aryl halides will react. (Vinyl acyl compounds do not exist).

 Rearrangements do not occur.

 Polysubstitution will not occur. (The reagent is more reactive than the product.)

  1. Reduction of Nitro Groups
    forming Aromatic Amines:
  2. Alkali Fusion of Aromatic Sulfonates
    forming Phenols:

Nucleophilic Aromatic Substitution (NAS):
Aromatic compounds with a halogen ortho- or para- to one or more nitro-groups are weak electrophiles. Nucleophiles such as OH-, OR- and NH3 will substitute for (replace) the halogen.

  1. Nitrophenols by NAS:
  2. Nitroamines by NAS:
  3. Oxidation of Alkylbenzene
    Side Chains:
    Benzylic C's with one or more H's are oxidized to carboxylic acids
  4. Bromination of Alkylbenzene
    Side Chains:
    NBS (N-bromosuccinimide), in the presence of a peroxide, releases bromine free radicals (Br) which brominate the benzylic carbon rather than the ring.
  5. Catalytic Reduction of Aromatics and Aryl Alkyl Ketones (from F.C. Acylations):

ALCOHOLS

Preparation:

  1. Hydrolysis of Methyl or
    of 1º alkyl halides:
    (2 or 3  alkenes by E2)
  2. Hydration (possible C+ rearrangement)
    or Hydration by
    Oxymercuration/Demercuration:
    (without C+ rearrangement)
    Hydration by
    Hydroboration/Oxidation:
    (AntiMarkovnikov product):
  3. Hydride Reduction of
    Aldehydes,
    Ketones,
    Esters &
    Carboxylic Acids:
  4. Grignard Reduction of
    Aldehydes,
    Ketones &
    Esters:
    (Grignard may be alkyl,
    aryl or vinylic but cannot
    be prepared when acidic
    groups are present
    with the halide)

ALCOHOL REACTIONS

  1. Dehydration to Alkenes:
  2. Conversion to Alkyl Halide:
  3. Neutralizing a Strong Base:
    (Alcohols have pKb ca. 16 like H2O)
  4. Oxidation of Alcohols:
  5. Reduction to Alkanes:
    a) Dehydrate to alkenes (1. above), then hydrogenate (H2 / Ni) to alkane
    or
    b) Prepare alkyl tosyate (good leaving group), then replace with H:- (following)

THIOLS

Preparation:

(from hydrogen sulfide, H2S
and then hydrosulfide, HS- )

Reactions:

  1. Reaction as acid
    with a base:
  2. Sulfide formation by
    substitution (SN2) with
    Me, 1, or 2 alkyl halides:

ETHERS s

Williamson Ether Synthesis:
[alkoxide substitution (SN2)
with Me or 1 alkyl halide]
Epoxide Ring Opening:
(Most ethers are unreactive but
epoxides are reactive because
of their high ring strain.)

ALDEHYDES & KETONES

Preparation of Aldehydes:

  1. Mild Oxidation of 1 Alcohols:
  2. Reduction of Carboxylic Acid
    Derivatives:
    (use 1 equivalent of a mild hydride, i.e.,
    DIBAH in cold inert solvent @ -78C)

Preparation of Ketones:

  1. Oxidation of 2 Alcohols:
    (mild or moderate oxidants)
  2. Oxidative Cleavage of
    substituted alkenes:
  3. Friedel Crafts Acylation
    of Aromatics:

 As with F.C. Alkylation, the aromatic ring must be as reactive as a halobenzene (and fails with animo groups)

 Aryl halides will react. (Vinyl acyl compounds do not exist).

 Rearrangements do not occur.

 Polysubstitution will not occur. (The reagent is more reactive than the product.)

  1. Hydration of Alkynes:
    (non symmetrical internal
    alkynes give mixed products)
  2. Acid chloride + Gilman Reagent:
    (a mild Grignard-like reagent, R’2CuLi
    in cold inert solvent @ -78C)

Reactions of Aldehydes and Ketones:

  1. Oxidation of
    Aldehydes
    & Ketones:
    (aldehydes are easily oxidized)
    (ketones are not easily oxidized
    except under severe conditions.
    The enol isomer is cleaved.)

  1. Hydration of
    Aldehydes
    & Ketones:
    [acid(H3O+) or base (OH-) catalysis
    is required as H2O is a weak Nu:-]
    (equilibrium favors the carbonyl)
  2. Addition of HCN
    forming a cyanohydrin:
    (the cyanohydrin can be
    reduced to an amine or
    hydrolyzed to an acid)
  3. Addition of Alcohols
    forming Acetals (diethers):
    (useful as protecting groups
    which are inert to strong bases)
    [Reaction is reversible. Use
    anhydrous acid to form acetal
    and aqueous acid back to the
    original aldehyde or ketone]
  4. Grignard Reduction of
    Aldehydes to 2 Alcohols
    &
    Ketones to 3 Alcohols:
  5. Hydride Reduction of
    Aldehydes to 1 Alcohols
    &
    Ketones to 2 Alcohols:
  6. Reduction of Carbonyl (C=O)
    group to Methylene (CH2) group
    by Wolf Kishner (N2H4 + KOH)
    or Clemmensen (Zn[Hg] + H3O+)
  7. Addition of 1 Amines
    forming Imines
    or
    2 Amines
    forming Enamines:

Examples of Imines:
(Derivatives)

  1. Conjugate 1,4-Addition
    of 1 equiv. of Amine
    or
    1 equiv. of Gilman Reagent:
    (In , -unsaturated carbonyls,
    addition occurs at the -carbon
    and the -carbon is saturated
    while the carbonyl is unreacted)
    [It only works with these 2 reagents.
    Other nucleophiles add directly to
    the carbonyl C]
    (Excess amine or Gilman reagent
    will add to the carbonyl carbon
    after the  and -carbons are
    saturated)

CARBOXYLIC ACIDS

Preparation:

  1. Oxidation of Alkylbenzene
    Side Chains:
    (Benzylic C's with one or more H's
    are oxidized to carboxylic acids)
  1. Oxidation with Cleavage:
  2. Oxidation of 1 Alcohols:
    (with moderate oxidants)
  3. Oxidation of Aldehydes:
    (mild or moderate oxidants)
  4. Hydrolysis of Nitriles:
    (acidic or basic hydrolysis)
  5. Grignards are
    Carboxylated:

Reactions:

  1. Reduction with
    LiAlH4 or BH3
    in THF solvent:
  2. Neutralization with
    a base:

  1. Conversion to
    Acid Chloride:
  2. Dehydration to
    Acid Anhydride:
    (Reaction is reversible.
    Anhydride can be
    hydrated back to
    2 carboxylic acids)

ORANOMETALLICS

Preparation:

  1. Organosodium or
    Organolithium:
    (Finely dispersed metal is
    added to dilute RX in HC solvent)
  2. Wurtz Coupling:
    (When Na is not dispersed, Me
    or 1 RX react with R-Na via SN2)
  3. Grignard Reagents:
    (Finely divided Mg in ether
    is inserted between any R-X bond)
  4. Gilman Reagent:
    (Any alkyllithium complexes
    with CuI in ether)

Reactions:

  1. Organosodium/lithium
    converted to alkanes:
    (And other reactions
    where R is nucleophilic)
  2. Grignards converted
    to alkanes:
    (And other reactions
    where R is nucleophilic)
  3. Substitution with any
    RX forming larger alkanes:
    (And other reactions
    where R is nucleophilic)

1

ORGANIC REACTIONS