Review ketone aldehyde CO very polar O C

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Review ketone aldehyde C=O very polar : O : C Nucleophilic addition - :

Review ketone aldehyde C=O very polar : O : C Nucleophilic addition - : O : C + + + H O H Nu C Nu - H-Nu H-OH H-OR H-NH 2

Nucleophilic addition R R . . C=O. . H+ R. . R C =O.

Nucleophilic addition R R . . C=O. . H+ R. . R C =O. . H R H+ R + H-OH R R . . C=O. . + H-OR + H-NH 2 R R . . O. . H C. . O. . . H H R N H H R R C O-H + H+ O-H hydrate or diol R C R O-H + H+ O-R hemi-ketal R RR R + H+ C O+-HH 2 O N N -H H 2 Schiffs base

Addition of alcohol H 3 H C H 3 C C O + CH

Addition of alcohol H 3 H C H 3 C C O + CH 3 OH H+ CH 3 H H 3 C C OH ketone + alcohol = hemi- ketal unstable aldehyde + alcohol = hemi- acetal unstable OCH 3

Nucleophilic substitution. . + OH. . - CH 3 - CH 2 O -

Nucleophilic substitution. . + OH. . - CH 3 - CH 2 O - CH 2 - CH 3 hemi - acetal . . H 3 C C . . OH. . H + H H. . O - CH H+ H 3 C C. . OH 2 3 O - CH 2 - CH 3 H 2 O H H 3 C C O - CH 2 - CH 3 aldehyde + alcohol acetal condensation reaction hemi-acetal + alcohol acetal + H 2 O + H+

acetal propanal + 2 equivalents ethanol stable hemi- ketal 2 -butanone + 1 equivalent

acetal propanal + 2 equivalents ethanol stable hemi- ketal 2 -butanone + 1 equivalent methanol unstable

Hydrolysis reverse reaction hemi-acetal + alcohol hemi-ketal + alcohol H OH H+ “breaking water”

Hydrolysis reverse reaction hemi-acetal + alcohol hemi-ketal + alcohol H OH H+ “breaking water” acetal + H 2 O ketal + H 2 O

Carboxylic acids 1 o alcohol [O] methanol H-bond acceptor H-bond donor aldehyde methanal [O]

Carboxylic acids 1 o alcohol [O] methanol H-bond acceptor H-bond donor aldehyde methanal [O] carboxylic acid methanoic acid - - + very high b. p. 2 H-bonds / molecule

Carboxylic acids Nomenclature 1. Carboxyl group (COOH) always C 1 2. Family name is

Carboxylic acids Nomenclature 1. Carboxyl group (COOH) always C 1 2. Family name is longest C chain with COOH 3. Suffix is “-oic acid” 4. Carbonyl groups (C=O) called “oxo” Hydroxy groups (OH) called “hydroxy”

Carboxylic acids 4 3 2 1 CH 3 – CH 2 – CH –

Carboxylic acids 4 3 2 1 CH 3 – CH 2 – CH – C O 2 -ethylbutan oic acid OH CH 2 – CH 3 O OH CH 2 – CH 3 – CH 2 – CH – CO 2 H 6 5 add [O] 4 3 2 1 2 -ethyl 4 -hydroxy 2 -ethyl- 4 -hydroxyhexan oic acid 2 -ethyl- 4 -oxo hexan oic acid

Carboxylic Acids Chemical properties = C=O + OH = Bronsted acid H+ donor HA

Carboxylic Acids Chemical properties = C=O + OH = Bronsted acid H+ donor HA H+ + AH+ + weak acids, small dissociation Ka = [A-] [H+] [HA] Ka 1 x 10 -5 p. H 2. 5 for 1 M

Carboxylic Acids H+ + - resonance structure anion stabilized

Carboxylic Acids H+ + - resonance structure anion stabilized

Carboxylic Acids acidity also affects solubility soluble H-bonding short chain acids long chain acids

Carboxylic Acids acidity also affects solubility soluble H-bonding short chain acids long chain acids insoluble benzoic acid add a strong base (OH-) LDF - soluble ion-dipole

Reactions Acid-base reactions: + Na. OH Na+ + H 2 O octanoic acid insoluble

Reactions Acid-base reactions: + Na. OH Na+ + H 2 O octanoic acid insoluble sodium octanoate + water soluble

Reactions Reduction: 6 5 4 Li. Al. H 4 3 2 1 5 -oxo

Reactions Reduction: 6 5 4 Li. Al. H 4 3 2 1 5 -oxo hexanoic acid 1, 5 - hexanediol H 2/ Pt Na. BH 4 5 -hydroxyhexanoic acid