One-pot synthesis of macrocyclic dioxatetralactones from the sequential inter-and intramolecular [2+2] photocycloaddition reactions

摘要

Sensitized photocycloaddition reactions of polymethylenedioxy-di-2-pyrones (1-3) with ethylene diacrylate (4a) afforded macrocyclic dioxatetralactones (6a-8a) having sixteen-to eighteen-membered rings. Similar reaction of 1 with ethylene dimethacrylate (4b) afforded similar lactones (6b) and (9). The stereochemical features of 6a and 7a depending on the chain length elucidated by the X-Ray crystal analysis are figured by MOPAC conformational analysis of the reactants (1,2 and 4a).