Synthesis of Optically Active Cyclopenta[c]pyran-4-carboxylic Acid Derivatives, Building Blocks for Iridoids. An Attractive Alternative to Asymmetric de Mayo Reaction

Abstract
A new asymmetric de Mayo reaction leading to enantiomerically pure iridoids has been elaborated using chiral spirocyclic dioxinone as the photochemical equivalent of diformylacetate.