Hantzsch pyrrole synthesis on solid support

An efficient method for solid-phase synthesis of pyrroles is described. Polystyrene Rink amide resin is acetoacetylated and converted into polymer bound enaminones upon treatment with primery amines. These then undergo a Hantzsch reaction with α-bromoketones to yield pyrroles. After cleavage with 20% trifluoroacetic acid in dichloromethane pyrrole-3-carboxamides are obtained in excellent purity.