Clay Catalyzed Reactions of Indole and its Methyl Derivatives with α, β-unsaturated Carbonyl Compounds

Electrophilic substituons reactions of indole and 1-methylindole with methyl propiolate in the presence of K-10 montmorillonite were obtained the formation of the corresponding methyl 3,3-bis(indolyl)propanoates. The reaction of 1,3-dimethylindole with methyl propiolate was given methyl 3,3-bis(1,3-dimethyl-1H-indol-2-yl)propanoate, methyl 1,5-dimethyl-1H-benzo[b]azepine-3-carboxylate and methyl 3,3,3-tris(1,3-dimethyl-1H-indol-2-yl)propanoate. The reaction of 1,3-dimethylindole with 2-cyclopentenone was yielded a typical addition product, similarly the reaction of indole and 1-methylindole with 2-cyclopentenone were concluded the expected addition products only.