1. SYNTHESIS OF AROMATIC HETEROCYCLES CONSTRUCTION OF THE RING SKELETON
Carbonyl condensation type reactions
Cycloadditions
with 1,3-dipoles
with ortho-quinodimethanes (DA type react.)
Nitrene insertion
Carbonyl condensations

2. Strategy a) - 5-membered rings
Pyrrole
(Paal-Knorr Synthesis s 255)
Furan
Thiophene

3. Strategy a) - 6-membered rings

4. Strategy b 5-membered rings 6-membered rings Enol (or phenol) Enamin
(or anilin)

5. 1,3-Dipolar Cycloaddition
Only 5-membered rings
Alkene / alkyne
Ex. ozonolysis

6. Cycloaddition with ortho-Quinodimethanes
Electrocyclic
ring opening

7. Nitrene Insertion
Generation of nitrenes

8. React. of nitrenes

9. Nitrene insertion - Heterocyclic synthesis