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[摘要]：Thermal extrusion of SO2 from beta,beta'-sulfolenoporphyrins is an effective method for in situ generation of beta,beta'-bis(methylene)porphyrin which remained unobserved in typical synthetic applications but underwent quickly efficient [4+2]-cycloaddition reactions with dienophiles.We now report the thermal extrusion of SO2 from the symmetrical (tetra-beta,beta'-sulfolenoporphyrinato)zinc 1.Zn in the absence of a dienophile (Scheme). In the event, the thermally in situ generated conjugated diene underwent a [4+2] self-cycloaddition, to give the {spirobi[tri-beta,beta'-sulfolenoporphyrinato]}dizinc 4.2Zn. This chiral (racemic) spirobiporphyrinoid dizinc complex represents the combination of the closely positioned and interacting chromophores of a (porphyrinato)zinc and of a (beta-methylene-beta,beta'-dihydroporphyrinato)zinc. It carries six sulfoleno moieties that are still available for further SO2 extrusion and cycloaddition reactions. |
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