Cycloaddition Reactions of Furo[2,3-b]pyrroles

Abstract

Reactions of furo[2,3-b]pyrroles with dimethyl butynedioate and ethyl propynoate were investigated. The reaction course is influenced by the substituents on the fused system. Products of [4+2]cycloaddition to the furan ring leading to indole derivatives have been observed. In the case of the reaction of methyl 6H-furo[2,3-b]pyrrole-5-carboxylate (1a) with dimethyl butynedioate, products of [4+2]cycloaddition to the furan ring as well as of Michael addition to the pyrrole ring leading to N-substituted indole derivative 3 have been observed.