A Functionalized Spiro[chlorin-porphyrin]-Type ‘Dimer’ Dizinc Complex from Rapid [4+2] Self-cycloaddition of a Conjugated [β,β′-Bis(methylene)porphyrinato]zinc
✍ Scribed by Srinivas Banala; Paul Sintic; Bernhard Kräutler
- Book ID
- 102259452
- Publisher
- John Wiley and Sons
- Year
- 2012
- Tongue
- German
- Weight
- 322 KB
- Volume
- 95
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Abstract
Thermal extrusion of SO~2~ from β,β′‐sulfolenoporphyrins is an effective method for in situ generation of β,β′‐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 SO~2~ from the symmetrical (tetra‐β,β′‐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‐β,β′‐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 (β‐methylene‐β,β′‐dihydroporphyrinato)zinc. It carries six sulfoleno moieties that are still available for further SO~2~ extrusion and cycloaddition reactions.