Δα,β-Butenolides [Furan-2(5H)-ones]: Ring Construction Approaches and Biological Aspects - A Mini-Review

The five-membered oxacyclic system of furan-2(5H)-ones, commonly named as γ- butenolides or appropriately as Δ^{α,β}-butenolides, is of high interest since many studies have proven its bioactivity. During the past few years, Δ^{α,β}-butenolides have been important synthetic targets, with several reports of new procedures for their construction. A short compendium of the main different synthetic methodologies focused on the Δ^{α,β}-butenolide ring formation, along with selected examples of compounds with relevant biological activities of these promising pharmaceutical entities is presented.