Synthesis and Cytotoxicity Studies of Bioactive Benzofurans from Lavandula agustifolia and Modified Synthesis of Ailanthoidol, Homoegonol, and Egonol

Abstract

2-Aryl/alkylbenzofurans, which constitute an important subclass of naturally occurring lignans and neolignans, have attracted extensive synthetic efforts due to their useful biological activities and significant pharmacological potential. Herein, we report a general and efficient approach to divergent 2-arylbenzofurans through a one-pot synthesis of versatile 2-bromobenzofurans as key intermediates. Using this approach, the first total synthesis of a series of trisubstituted and tetrasubstituted benzofurans bearing the hydroxyethyl unit, including the natural compounds isolated from Lavandula agustifolia (1-3) and their non-natural derivatives (4-8), was accomplished. We also report a modified synthesis of ailanthoidol, homoegonol, and egonol that enables the divergent synthesis of their derivatives for future exploration. Among these, the representative phenolic natural compound 2 and its derivatives 7 and 5 induced apoptotic cell death related poly(ADP-ribose) polymerase (PARP) cleavage in MCF74, A549, PC3, HepG2, and Hep3B cancer cell lines. Additionally, the tumor suppressor protein p53 was also induced in p53 wild type cancer cells.