Synthesis of novel tricyclic and tetracyclic sultone scaffolds via intramolecular 1, 3-dipolar cycloaddition reactions

The initially prepared 2-formylphenyl-(E)-2-phenylethenesulfonates from the condensation of (E)-2-phenylethenesulfonyl chloride with 2-hydroxybenzaldehyde derivatives underwent intramolecular [3+2] cycloaddition with methyl or phenylhydroxylamine, sarcosine, and L-proline, affording the corresponding novel isoxazolidine, pyrrolidine and pyrrolizidine-annulated gamma,delta-benzo-delta-sultones, respectively, in good yields. Unambiguous assignment of the molecular structures was carried out by single-crystal X-ray diffraction. (C) 2012 Elsevier Ltd. All rights reserved.