Traceless solid-phase synthesis of hydroxylated cyclopentenones

Intramolecular nitrone–alkene cycloadditions on solid phase can be performed using polymer-bound hydroxylamine. Condensation of this reagent with sugar derived 4-pentenals followed by N–O cleavage, quaternization of the amine thus produced, and finally oxidative elimination of the amino group detaches the chiral hydroxylated cyclopentenones from the polymer. The natural antibiotic pentenomycin I was prepared in this way.