Chemistry of Cyclopentadienones

Ogliaruso, Michael A.; Romanelli, Michael G.; Becker, Ernest I.

doi:10.1021/cr60235a001

Cited by 330 publications

(166 citation statements)

References 141 publications

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“…MALDI MS analysis revealed only two products in the reaction mixtures (i.e., Ar 2 TBPs 8a-d) and the Diels-Alder adducts of the intermediate porphyrins and tetracyclone, which were aromatized by way of CO extrusion. 47 The byproduct did not form in large quantities, and Ar 2 TBPs could be purified by chromatography.…”

Section: Aromatization Of Ar 2 Tchpsmentioning

confidence: 99%

Synthesis of 5,15-Diaryltetrabenzoporphyrins

et al. 2008

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A general method of synthesis of 5,15-diaryltetrabenzoporphyrins (Ar 2 TBPs) has been developed, based on 2 + 2 condensation of dipyrromethanes followed by oxidative aromatization. Two pathways to Ar 2 TBPs were investigated: the tetrahydroisoindole pathway and the dihydroisoindole pathway. In the tetrahydroisoindole pathway, precursor 5,15-diaryltetracyclohexenoporphyrins (5,15-Ar 2 TCHPs) were assembled from cyclohexeno-fused meso-unsubstituted dipyrromethanes and aromatic aldehydes or, alternatively, by way of the classical MacDonald synthesis. In the first case, scrambling was observed. Aromatization by tetracyclone was more effective than aromatization by DDQ but failed in the cases of porphyrins with electron-withdrawing substituents in the meso-aryl rings. The dihydroisoindole pathway was found to be much superior to the tetrahydroisoindole pathway, and it was developed into a general preparative method, consisting of (1) the synthesis of 4,7-dihydroisoindole and its transformation into meso-unsubstituted dipyrromethanes, (2) the synthesis of 5,15-diaryloctahydrotetrabenzoporphyrins (5,15-Ar 2 OHTBPs), and (3) their subsequent aromatization by DDQ. Ar 2 TBP free bases exhibit optical absorption spectra similar to those of meso-unsubstituted tetrabenzoporphyrins and fluoresce with high quantum yields. Pd complex of Ph 2 TBP was found to be highly phosphorescent at room temperature.

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Section: Aromatization Of Ar 2 Tchpsmentioning

confidence: 99%

Synthesis of 5,15-Diaryltetrabenzoporphyrins

et al. 2008

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“…The decarbonylations of A3-cyclopentenones and A3-2-oxacyclopentenones are facile, common, and synthetically useful (4,27). T h e kinetic data for the cycloelimination of carbon nlonoxide from dicyclopentadiene-1,s-dione are consistent with, but do not require, a concerted n~echanisnl for the reaction.…”

Section: Discussionmentioning

confidence: 68%

Cycloadditions: X. Kinetics of the Thermal Decarbonylation of DICYCLOPENTADIENE-1.8-DIONE

Baldwin¹

1966

Can. J. Chem.

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'I'he thermal cycloelimination of carbon ~nonoxide fro111 dicyclopentadiene-1,s-dione is a kinetically well-behaved first-order reaction. At 380 'I< the activation parameters for the process are AH' = 34.5 =t 0.8 lccal mole-' and A S + = $9.8 =t 2.3 e.u. mole-1. Application of the theoretical proposals of Woodward and Hoffmann indicates that this necessarily disrotatory decarbonylation may be concerted.

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“…13 A similar preparation of thiophene S-oxides via dibenzyl sulfoxide (16) has not been reported thus far. Thiophene S-oxides 2 and also benzothiophene S-oxides 4 are much more sensitive than their dioxide counterparts.…”

mentioning

confidence: 99%

“…16 Tetraaryl-substituted thiophene S-oxides are pale yellow, while tetra-arylcyclopentadienones are dark purple. Thiophene S-oxides, however, do invert at the sulfur with different substituents at the C2/C5 positions leading to different barriers of inversion.…”

mentioning

confidence: 99%