PYRROL, THIOPHENE AND FURAN THEORY

The reaction of a 3-ketoester with an a -haloketone in a basic medium generates a furan.

furan feist benary 01

The reaction of carbonyl ylides with alkynes produces dihydrofurans.

13 dipolar furan

The Paal-Knorr synthesis generates thiophenes by reaction of 1,4-dicarbonyls with P 4 S 10

thiophene paal knorr 01

The reaction of thiocarbonyl ylides with alkynes produces dihydrothiophenes

13 dipole thiophene