Chemistry 125: Lecture 71 April 20, 2011 Acids and Acid Derivatives Decarboxylation (J&F Ch. 17) Acyl Compounds (J&F Ch. 18) This For copyright notice see final page of this file

R-Li & LiAlH 4 (e.g. J&F Sec. 17.7f) stop at C=O?

Decarboxylation (e.g. J&F 17.7g) malonic acid  acid (concerted) OH 2 HO OH C O H O -CO 2 enol

R Kolbe Electrolysis -e--e- fast at 4K ! R R-RR-R R = CH 3 (Kolbe 1848) R = (~50% 1973) Decarboxylation (e.g. J&F 17.7g) or CO 2 as leaving group from XCO 2 - or RCO 2 (e.g. J&F pp ) H 2 O + carbonic acid NH 3 + carbamic acid

Decarboxylation (e.g. J&F 17.7g) or CO 2 as leaving group from XCO 2 - or RCO 2 (e.g. J&F pp ) RCO 2 Ag Br 2 RBr + AgBr + CO 2 “Hunsdiecker Reaction” RCO 2 H Ag 2 O R - Br R CO 2 Br 2 Patents

Decarboxylation (e.g. J&F 17.7g) or CO 2 as leaving group from XCO 2 - or RCO 2 (e.g. J&F pp ) Published in 1861 RCO 2 Ag Br 2 RBr + AgBr + CO 2 “Hunsdiecker Reaction” RCO 2 H Ag 2 O ? Tony award 1954 (Kismet) Alexander Porfiryevich Borodin KCN RC N RCO 2 H H2OH2O H + or HO -  R-MgBr Mg O=C=O RCO 2 MgBr + H+H+ “R + ” “R - ” A. Sdobnikov Patents

Acid Derivatives (e.g. J&F Ch. 18) X: O RC N RC nitrile H 2 C=C=O ketene H 3 C - CO 2 H H2OH2O R - CO 2 H +3 H2OH2O

1681 CH 3 C O NH 2 CH 3 -C=O(X) strong & independent 1727 CH 3 C O H 1715 CH 3 C O CH 3 CH 3 C O OCH CH 3 C O Cl n N  * C=O n O  * C-Cl n O  * C-OMe :: : C=O weakened by resonance C=O strengthened by resonance Spectroscopy (pp )

acyclic anhydride in phaseout of phase % Transmission %T

out of phase cyclic imide in phase

X-X- O RC Interconversion of Acid Derivatives (e.g. J&F pp. 886, 890, Figs ,18.22) - Y-Y- Tetrahedral Intermediate (A/D substitution, rather than pentavalent transition state as in S N 2) or acid-catalyzed (as in Fischer esterification) Leaving Group Hierarchy Cl - R’CO 2 - R’O - R’ 2 N - differences reinforced by resonance stabilization: + - H2OH2O transesterification K ~1 (shift by law of mass action) -8 ~5 ~16 ~35 RCO 2 H SOCl 2 H H H H pK a

Saponification K>>1 K ~10 11 OR - O RC - HO - OR - RO - HO - H pK a ~5 pK a ~16 Lye KOH soapglycerine triglyceride (fat) “I ain’t afraid to wash my hair in it.” “That there lard eats the lye.”

Going All the Way to C-OH (e.g. J&F pp. 891, 898-9, 903 (C-NH 2 ) )

Stopping Part Way to Preserve C=O (e.g. J&F pp (Fig ); 900 (Fig 18.38))

Acidic / Basic Hydrolysis of RCN pp C-OH O

Acidic Hydrolysis of RCN

Basic Hydrolysis of RCN

Acyl Compounds from Ketene (J&F Sec , p. 907) H 2 C=C=O Nu: HNu or H + catalyzed 93% pK a = 17 pK a = ~31 pK a = ~10 H 2 C=C=O H - SEt -80°, 3 days 75% Ph - N - CH 3 H EtOH / H 2 O H - OC(CH 3 ) 3 87% H+H+ pK a = ~35 (Nu = N) R3NR3N

Insertion into Acyl-R Bond

Munich 1896 Adolf v. Baeyer Victor Villiger

Baeyer-Villiger Reaction (insert O) (e.g. J&F pp )

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