Organic Chemistry

832 CHAPTER 19 Carbonyl Compounds III

12. Condensation of a ketone and an ester (Section 19.15).


13. Robinson annulation (Section 19.16).


14. Decarboxylation of 3-oxocarboxylic acids (Section 19.17).


15. Malonic ester synthesis: preparation of carboxylic acids (Section 19.18).


16. Acetoacetic ester synthesis: preparation of methyl ketones (Section 19.19).
    
    
    1. CH 3 CH 2 O−
    
    
    2. RBr
    
    
    3. HCl, H 2 O, ∆
    
    
    
    

O O O

CH 3 CCH 2 COC 2 H 5 RCH 2 CCH 3 + CO 2

1. CH 3 CH 2 O−


2. RBr


3. HCl, H 2 O, ∆

O O O

C 2 H 5 OCCH 2 COC 2 H 5 RCH 2 COH + CO 2

O O O

∆

RCCH 2 COH RCCH 3 + CO 2

H 2 O

∆

base

a Michael

reaction

an intramolecular

aldol addition

O

OOO

C

H 3 C

O

O

OH

CH 2 CHCCH 3 +

+

O

OOO

CR

1. CH 3 O−

• RCOCH (^3) 2. HCl + CH 3 OH
  O
  OOO
  CH

1. CH 3 CH 2 O−


2. HCl

excess

excess

excess

+ HCOCH 2 CH 3 + CH 3 CH 2 OH

O

OOO

COCH 2 CH 3

1. CH 3 CH 2 O−

• CH 3 CH 2 OCOCH 2 CH (^3) 2. HCl


• CH 3 CH 2 OH
  Key Terms
  acetoacetic ester synthesis (p. 822)
  aldol addition (p. 806)
  aldol condensation (p. 807)
  ambident nucleophile (p. 794)
  annulation reaction (p. 817)
  (p. 788)
  carbon acid (p. 789)
  Claisen condensation (p. 810)
  condensation reaction (p. 807)
  crossed aldol addition (p. 809)
  a-carbon decarboxylation (p. 819)
  Dieckmann condensation (p. 814)
  (p. 791)
  enolization (p. 792)
  gluconeogenesis (p. 826)
  b-diketone