Stepwise π-extension of meso-alkylidenyl porphyrins through sequential 1,3-dipolar cycloaddition and redox reactions

Park, Dowoo; Jeong, Seung Doo; Ishida, Masatoshi; Lee, Changhee

doi:10.1039/c4cc04283b

Cited by 12 publications

(11 citation statements)

References 25 publications

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“…This in turn could be oxidized with DDQ to afford the pyrrole-fused benzipentaphyrin 505 . A further cycloaddition–oxidation sequence afforded a dipyrrolo benzipentaphyrin (not shown) …”

Section: Benziporphyrins Heterobenziporphyrins and Related Systemsmentioning

confidence: 99%

Carbaporphyrinoid Systems

2016

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Following immediately after the serendipitous discovery of N-confused porphyrins, remarkably diverse carbaporphyrinoid systems have been synthesized and investigated. By replacing a pyrrolic unit within the porphyrin framework with cyclopentadiene, indene, azulene, cycloheptatriene, or benzene, new families of porphyrin-like macrocycles were produced. True carbaporphyrins are fully aromatic structures, while benziporphyrins are essentially devoid of macrocyclic aromatic character, and azuliporphyrins fall midway between the two extremes. Monocarbaporphyrinoids are superior organometallic ligands and form stable complexes with copper(III), silver(III), gold(III), nickel(II), palladium(II), platinum(II), rhodium(III), iridium(III), and ruthenium(II). Unusual oxidation reactions have also been discovered, commonly leading to derivatization of the internal carbon atom. In addition, structural rearrangements have been uncovered that allow the conversion of azuliporphyrins into benzocarbaporphyrins, and benziporphyrins into carbaporphyrins. Although less well studied, many examples of dicarbaporphyrinoids have been reported, and these show equally intriguing characteristics. Furthermore, contracted and expanded carbaporphyrinoids have been investigated. Studies in this area provide fundamental insights into the aromatic properties, tautomerization, and reactivity of porphyrins and related macrocyclic systems.

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“…This in turn could be oxidized with DDQ to afford the pyrrole-fused benzipentaphyrin 505 . A further cycloaddition–oxidation sequence afforded a dipyrrolo benzipentaphyrin (not shown) …”

Section: Benziporphyrins Heterobenziporphyrins and Related Systemsmentioning

confidence: 99%

Carbaporphyrinoid Systems

2016

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“…Similarly, thiophene dicarbinol 122b reacted with 121 to give thiabenziporphyrin 123b in 8% yield and an expanded product 124b in 1% yield. 72 In addition, condensation of naphthitripyrrane 126 with thiophene dicarbinol 122b in the presence of TFA, followed by oxidation with DDQ, gave a naphthiporphyrin system 127 with two exocyclic double bonds (Scheme 55). The X-ray structure of 123a showed that the ring system is severely puckered and the benzene subunit lies virtually at right angles to the rest of the macrocycle.…”

Section: Benziporphyrins With Exocyclic Double Bondsmentioning

confidence: 99%

“…71 Benziporphyrin 123c and the corresponding palladium(II) complex 123d have been shown undergo 1,3-dipolar cycloadditions with an azomethine ylide to give extended structures (Scheme 53) and similar chemistry was reported for benzipentaphyrin 125b. 72 In addition, condensation of naphthitripyrrane 126 with thiophene dicarbinol 122b in the presence of TFA, followed by oxidation with DDQ, gave a naphthiporphyrin system 127 with two exocyclic double bonds (Scheme 55). 73 As would be expected, none of these macrocycles exhibit aromatic properties.…”

Section: -Hydroxybenziporphyrinsmentioning

confidence: 99%

Benziporphyrins, a unique platform for exploring the aromatic characteristics of porphyrinoid systems

2015

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Benziporphyrins were first discovered over 20 years ago. Although initially they were considered to be a chemical curiosity, a wide range of benzene-containing porphyrinoid systems are now known that exhibit intriguing spectroscopic, structural and chemical properties. These systems can often generate stable organometallic derivatives, and have been shown to have applications in the development of chemical sensors and in molecular recognition studies. The characteristics of these porphyrinoid macrocycles vary from nonaromatic to highly aromatic systems, and in a few cases antiaromatic structures are formed. The variations in aromatic character are insightful and provide a deeper understanding of aromaticity and conjugation in porphyrinoid structures. In this review, the synthesis and properties of benziporphyrinoid systems is presented with a particular emphasis on the variations in aromatic characteristics.

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“…The azomethine ylide (prepared in situ by reaction of sarcosine and paraformaldehyde) reacted with meso-diethylmalonylidene-(m-benzi)pentaphyrin affording the pentaphyrin chlorin-type analog 114 in 49% yield (Figure 23). 95 After an oxidation step of the pyrrolidine ring, followed by reduction of the macrocycle with NaBH4, the resulting product was submitted to another 1,3-dipolar cycloaddition under the same conditions to afford the chlorin-type derivative 115 in 75% yield. The π-system delocalization can potentially be improved by submitting compound 115 to a new sequential oxidation and reduction protocol, affording a new derivative bearing two fused pyrrole-type moieties.…”

Section: Porphyrinoids In Cycloaddition Reactionsmentioning

confidence: 99%

“…Lee and co-workers 95 extended the 1,3-dipolar cycloaddition approach of azomethine ylides to prepare Pd(II) complex (benzi)chlorin 111 from the reaction of the precursor 110 and the azomethine ylide generated in situ at 90 °C in toluene for 1 h under N2. The bacteriochlorin-type derivative 112 was also isolated as a diastereomeric mixture in 39% yield, being obtained as the chlorin-type analog but only in vestigial amounts.…”

Section: Author(s)mentioning

confidence: 99%