Ochem Test 3 carboxylic reactions

Nitrile (R-CN) + Acid (aq) =

o Carboxylic acid

o SN2 reaction

o Tertiary alkyl halides = no rxn

Mechanism pg: 904

R-MgBr + 1)CO2, 2)H3O =

Carboxylic acid

Mechanism pg: 905

RCOOH + 1)LiAlH4, 2)H3O =

oAlcohol

Mechanism pg: 905-906

RCOOH + 1)BH3 THF =

Alcohol

Borane reacts selectively with a RCOOH when another C=O is present

Alkyne + 1)O3 2)H2O

Triple bond will break forming two carboxylic acids

(Alkyl group connected to Aromatic ring) + Na2Cr2O7, H2SO4, H2O

Alkyl group on aromatic ring will be completely oxidized into a carboxylic acid

primary alchohol + o Na2Cr2O7, H2SO4, H2O

Strong oxidizing agents will oxidize primary alcohols into carboxylic acids

Nucleophile + carboxylic acid derivative: (Cl, O, OR, NH2)

Nucleophile attacks carboxylic acid derivative, loss of leaving group "Z"

"Z" must be a heteroatom (Cl, O, OR, NH2)

RCOOH + SOCl2

o RCOCl

o 2 step mechanism

RCOCl + H2O

RCOOH

RCOCl + ROH, py

RCOOH

Steric effects

Mechanism pg: 918

RCOCl + NH3 (2 eq.)

o Rxn. can also occur with RNH2 and R2NH to produce N-substituted amides

RCOCl + 1)LiAlH4 2)H3O

Alcohol (or aldehyde)

RCOCl + RMgBr

Alcohol with R substituents

RCOCl + R2CuLi

Ketone with R substituents attached.

RCOOH + 800C (heat)

Carboxylic acid can be converted into acid anhydrides with excessive heating (800 °C)

This method can only work for acetic acid!!!

RCOCl + RCOO-

acetic anhydride

RCOOOCR + ROH

Acetylation of acetic anhydride with an alcohol can form an ester with the R group attached.

RCOOOCR + RNH2

Acetylation of acetic anhydride with an amine can form an amide

RCOOH + 1.) NaOH 2.) RX

o Strong base with alkyl halide will convert a carboxylic acid into an ester

o SN2 reaction

Tertiary alkyl halide = no rxn

RCOCl + 1.) ROH 2.) pyridine

Acid chloride + ROH = Ester

Ester + H3O

Carboxylic acid

This is the reverse of Fischer esterification

Mechanism pg: 928

RCCOH + NH3

Ester + amines = Amides

Ester + LiAlH4

Alcohol

Ester + RMgBr

Alcohol with R groups attached.

Same mechanism as Acid Chloride with Grignard reagent

Mechanism pg: 931

RCONH2 + H3O

Carboxylic acid

Reaction is slow and requires heat

Equilibrium favors formation of the products, reaction is irreversible

RCONH2 + 1.) NaOH 2.) H3O

Carboxylic acid

Amide + reducing agent

amine

Carbonyl group is completely removed

Alkyl halide + cyanide ion

Nitrile

SN2 reaction

Tertiary alkyl halides

no rxn.

RCONH2 + SOCl2

Dehydration of Amides to produce a Nitrile

Mechanism pg: 936

RCN + H3O

Nitrile = amide = carboxylic acid

Nitrile + 1.) RMgBr 2.) H3O

Ketone

Nitrile + LiAlH4, H2O

amine

What factors effect reactivity to nucleophiles?

steric effects and # of R groups. The more R groups the LESS reactive

Which is more reactive towards nucleophiles aldehydes or ketones?

aldehydes

Aldehyde

Esther

Mechanism of Hydration

1. H3O+ donates hydrogen to ketone

2. Double bond donates a pair to oxygen

3. The remaining H2O attaches to the carbonyl carbon

4. Hydrogen leaves the water and gets attached to a floating water molecule

5. Remaining structure has two OHs with trans stereochemistry

Cyanohydrin formation

1. When a HCN or KCN attaches to carbonyl carbon and double bond gives back to oxygen

2. Oxygen gets Hydrogen from nitrile

3. End product is OH and CN attached to the carbonyl carbon

Imine formation

1. Amine attaches to carbonyl carbon and double bond feeds oxygen

2. H attaches to the Oxygen

Imine

What happens to natural carbinolamine at high ph?

It is deprotonated

What is the alpha carbon

The carbon closest to the carbonyl carbon

Enamine

What happens during enamine formation

alpha carbon donates hydrogen bond to create double bond between carbonyl carbon and alpha carbon

Wolf-Kischner reaction works for?

aldehydes and ketones ONLY

Wolf-Kischner reaction mechanism

1. N4H2/KOH catalyst

2. Imine

Acetal formation

Wittig reaction

Ylene and Yline

Ylide prep

Wittig reaction

Cannizzaro reaction

Requirements for cannizzaro:

1. Carbonyl MUST be aldehyde

2. The alpha-carbon of the aldehyde must NOT have a hydrogen atom