D. Xiao et al., REVERSIBLE FRIEDEL-CRAFTS ACYLATIONS OF 3-ALKYL-1-(PHENYLSULFONYL)PYRROLES - APPLICATION TO THE SYNTHESIS OF AN ANT TRAIL PHEROMONE, Tetrahedron letters, 37(10), 1996, pp. 1523-1526
Friedel-Crafts acylations of 3-alkyl-1-(phenylsulfonyl)pyrroles appear
to be kinetically favored at the adjacent C-2 position but rearrangem
ent to the C-5 position can occur after prolonged reaction times. This
reversible Friedel-Crafts methodology has been employed for the synth
esis of the ant nail pheromone, methyl 4-methylpyrrole-2-carboxylate.