exam 3 reactions + reactants + mechanisms

Oxidation of alcohols into carbonyls

1^o alcohol + PCC → aldehyde
2^o alcohol + PCC → ketone
Allylic or benzylic alcohol + MnO2 → aldehyde or ketone depending on 1^oor 2^o

Oxymercuration of alkynes

Alkyne + Hg(SO4) + H2SO4 + H2O → enol → ketone via tautomerization
markovnikov rule

hydroboration of alkynes

if alkyne has one substituent:
Alkyne + 1. BH3 + 2. NaOH, H2O2 → enol → aldehyde
antimarkovnikov

Ozonolysis of alkenes

Alkene 1. O3 2. S(CH3)2 → aldehyde or ketone depending on substituents on alkene
Alkene 1. O3 2. H2O2, H2O → carboxylic acid

Recall that ozonloysis splits the C=C

Oxidation of diols

diol = 2 alcohols next to each other
Diol + HIO4 + PB(oAC)4 → 2 ketones/adehydes based on substituents of diol

2 because it splits the diol in half between the 2 alcohols and turns them into a C=O

Irreversible addition of Nu- to carbonyls vs reversible

Carbonyl (sp2) + strong anionic Nu- → Nu- attaches to the carbonyl and the C=O becomes C-O^- (sp3), irreversible

Carbonyl + weak protic HNu → Nu attaches, C=O becomes C-OH, reversible equilibrium

cyanohydrin formation*

Reversible addition of Nu- to carbonyl examples
Carbonyl + HCN → cyanohydrin (NC-C-OH)

hydrate formation - acid catalyzed hydration of C=O*

Reversible addition of Nu- to carbonyl examples
Carbonyl + H3O⁺ cat + H2O → hydrate (2OH on 1C, unstable)
Less stable carbonyl (more EWG) = more hydrate

acetal formation*

Reversible addition of Nu- to carbonyl examples
Carbonyl + 2eq R’OH + cat H⁺ → acetal (2OR on same carbon) + H2O
Add acid to favor carbonyl, remove water or use excess ROH to favor acetal

carbonyl reaction with amines*

Reversible addition of Nu- to carbonyl examples
Carbonyl + 1^o amine + cat H⁺ → Imine (the N attaches to the C in place of the O, RN=C, so it loses the 2 Hs) + H2O
Favor Imine by removing H2O

Carbonyl + 2^o amine + cat H⁺ → enamine + H2O (N attaches to C in place of O, so it loses 1 H and the C loses 1 H, R2N-C=C)

Hydride addition to carbonyls*

Carbonyl 1. LiAlH4 2. H3O+ → ROH
Carbonyl + CH3OH + NaBH4 → ROH

Adds an H+ to the O and an H- to the C

LiAlH4 is more reactive than NaBH4 because Al is less electronegative than B and dumps more e- onto the H

Carbanion making

Alkyl halide + Mg⁰ + Et2O → R-MgBr
Alkyl halide + Li⁰ → R-Li

Alkyne + NaNH2 → R-Alkyne-Na

Modular synthesis of ROH

Carbonyl 1. grignard 2. H3O+ → ROH → 1^o, 2^o, 3^o depends on substitution on carbonyl

Alkene synthesis from carbonyl

carbonyl 1. grignard 2. H3O+ → Alcohol → H2SO4 → alkene (major vs minor)

Acetals as protecting groups

can temporarily remove C=O to form acetal and acetals do not react with grignards

Wolff kishner reaction and clemmenson reaction

Interchangeable: overall C=O → H-C-H

W-K:
Carbonyl + NH2NH2, KOH, heat → replace the O with 2 Hs + N2 + H2O

Clem:
carbonyl + Zn/Hg + HCl → replace O with 2 Hs

we can use these to convert m directing carbonyl groups to o,p directing groups
Also, X-carbonyls do not have C+ rearrangement when reacting in EAS, but X-R do, so we can avoid C+ rearrangement and then convert them into an alkyl group

Wittig Reaction*

carbonyl + phosphonium ylide =PPh3 (2 adjacent charges) → replace C=O with alkene, cis alkene favored + O=PPh

Ylide synthesis: CH3-Br + :PPh3 → SN2 phosphonium ion Ph3P⁺-CH3 + Br^- + KOtBu → Ph3P=

Wittig allows us to control regioselectivity and help us form the more unstable product as the major product

unselective Oxidation of aldehydes to carboxylic acids

Aldehyde or aryl substituents or 1^o/2^o alcohols 1. KMnO4, NaOH, H2O → RCOOH
aldehyde or ROH + H2Cr2O7 + H2O → RCOOH

Unselective, can oxidize alkenes too and slice em in half

Selective oxidation of aldehydes to COOH

Aldehyde + Ag2O, NaOH, THF/H2O → selective oxidation of aldehyde only to COOH

Oxidation of grignards to Co2*

R-MgBr 1. CO2 2. H3O+ → R-COOH

RCOOH with HNu

RCOOH + HNu → Substitution, Nu replaces OH group because it is a built in leaving group!!

Fisher esterification*

R-COOH + ROH + H⁺ cat → R-COOR + H2O (equilibrium, remove H2O to push eq right)

SN2 of RCOOH with alkyl Halides*

R-COOH + R-X + K2CO3 → R-COOR + K-X + KHCO3

conversion of RCOOH to acid chloride*

RCOOH + SOCl2 → RC=OCl

Conversion of COOH to anhydrides

2 eq R-COOH + P2O5 (dehydrating agent) → anhydride (2 carbonyls connected by an O O=C-O-C=O) + H2O

Hydride reagents + RCOOH*

RCOOH + NaBH4 → no reaction, COOH is less reactive and electrophilic than an aldehyde

RCOOH + 1. LiAlH4 2. H3O⁺ → double addition of H in place of the O (get a primary ROH)

Decarboxylation*

RCOOH + heat → ketone + CO2, needs a beta carbonyl group (RC=O-C-COOH)

staircase of electrophilicity of RCOOH and derivatives

Acid chloride → anhydride → RCOOH, RCOOR → carboxylate (RCOO^-) → RCONR2, RCN)

Eas