Sulfolenoporphyrins: synthons for refunctionalization of porphyrins

Using sulfolenopyrroles (4) and (11) methods are developed for the synthesis of opp- (15,18,19) and adj- (25) bis-sulfolenoporphyrins; such compounds are useful building blocks for the refunctionalization of the porphyrin system, and readily undergo Diels–Alder cycloaddition reactions.