The aldol condensation between a phosphonate aldehyde and dihydroxyacetone phosphate catalyzed by fructose 1,6-diphosphate aldolase (EC 4.1.2.13) gives a product which in situ cyclizes via an intramolecular Horner-Wadsworth-Emmans (HWE) olefination to afford a polyhydroxylated cyclopentene. In this one-pot reaction, the HWE reaction takes place in aqueous solution at slightly acidic (pH 6.1-6.8) conditions.