A divergent synthetic approach to tricyclic Furo[3,2-e]indolizines via base-mediated tandem annulations of diethyl malonate with aromatic bromomethyls

Abstract

A base-promoted, transition-metal-free one-pot method for the divergent synthesis of tricyclic furo[3,2-e]indolizines is described. The reaction of 1-(2-oxo-2-phenylethyl)-1H-pyrrole-2-carbaldehyde, diethyl malonate, and aromatic bromomethyl derivatives proceeds through a tandem Knoevenagel–aldol annulation, O-alkylation, and intramolecular cyclization to afford the corresponding furoindolizine products in good to excellent yields. The protocol employs readily accessible starting materials, operates under simple and transition-metal-free conditions, and enables the rapid construction of structurally diverse furo[3,2-e]indolizine frameworks. These features highlight the synthetic efficiency and practical applicability of the approach, making it a valuable platform for heterocyclic synthesis and potential applications in medicinal chemistry.