Is Through-Bond Dihydroaromaticity Attainable? Preparation of [4,5]Dihomotropone, Investigation of Its Ground-State Properties, and an Attempt to Generate the Dihomotropylium Cation

Paquette, Leo A.; Watson, Timothy; Friedrich, Dirk; Bishop, R.; Bacqué, Eric

doi:10.1021/jo00098a031

Cited by 13 publications

(11 citation statements)

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“…Paquette et al prepared the dihomotropone 58 and concluded from its IR, UV, and NMR spectra that there was no evidence for the homoaromatic chargeseparated species 59. 74 properties, 13 C NMR chemical shifts, 75 magnetic susceptibility exaltation 23,33 and NICS 33 confirm the homoaromaticity of 63. Arnold and Chan reinvestigated the isodesmic reaction 1 and other features of this system using ab initio and DFT methods.…”

Section: Potential Homoaromaticsmentioning

confidence: 65%

Homoaromaticity

2001

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Section: Potential Homoaromaticsmentioning

confidence: 65%

Homoaromaticity

2001

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“…Extended conjugated -systemsespecially aromatic onesexpress particular reactivity and show the ability to absorb energy in the UV/vis range. To further elucidate the homoaromatic character of 15 we investigated its behavior upon irradiation with light, as has been done for several other homoaromatic compounds 20,27,28,45 . We found that homoannulene ester 15 undergoes a photoinduced rearrangement of the barbaralone framework forming ester 18 (305 nm LED irradiation for 80 sec of a dilute cyclohexane or MeCN solution of 15, Fig.…”

Section: Resultsmentioning

confidence: 99%

Photoswitching neutral homoaromatic hydrocarbons

Ngoc

Grabicki²,

Irran

et al. 2022

Preprint

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The identification and characterization of homoaromatic compounds bearing an interrupted -system are fundamental challenges for the understanding of electronic interactions in organic molecules. This is further hampered by the fact that no stable neutral homoaromatic hydrocarbon is known. We present the preparation of a new class of neutral homoaromatic compounds, which are supported by experimental evidence (ring current observed by NMR spectroscopy, equalization of bond lengths through X-ray structure analysis) as well as computational analysis (NICS and ACID). Furthermore, we show that one homoaromatic hydrocarbon is a photoswitch through a reversible photochemical [1,11] sigmatropic rearrangement. We provide evidence that the local 6 homoaromatic state vanishes upon photoswitching to produce a purely global 10 homoaromatic state. These results of stable and accessible homoaromatic neutral hydrocarbons and their photoswitching behaviour provide new insights for the understanding and study of homoconjugative interactions in organic molecules, and for the design of new responsive molecular materials.

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“…For clean bromination-dehydrobromination reactions, ketone 11e was first converted to its ethylene ketal 17 using classical methods. 21 Monobromination of 17 was carried out with slow addition of bromine (1 equiv) in ethyl ether at room temperature. Monobrominated ethylene ketal 18 was obtained in high yield (90%).…”

Section: Chemistrymentioning

confidence: 99%

“…We then prepared compounds 23 and 25 containing exclusively E double bonds derived from symmetrical keto diester 11e as depicted in Scheme . For clean bromination−dehydrobromination reactions, ketone 11e was first converted to its ethylene ketal 17 using classical methods . Monobromination of 17 was carried out with slow addition of bromine (1 equiv) in ethyl ether at room temperature.…”

Section: Chemistrymentioning

confidence: 99%

Synthesis and Glutathione S-Transferase Structure−Affinity Relationships of Nonpeptide and Peptidase-Stable Glutathione Analogues

et al. 1998

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A series of nonpeptidic glutathione analogues where the peptide bonds were replaced by simple carbon-carbon bonds or isosteric E double bonds were prepared. The optimal length for the two alkyl chains on either side of the mercaptomethyl group was evaluated using structure-affinity relationships. Affinities of the analogues 14a-f, 23, and 25 were evaluated for a recombinant GST enzyme using a new affinity chromatography method previously developed in our laboratory. Analysis of these analogues gives an additional understanding for GST affinity requirements: (a) the carbon skeleton must conserve that of glutathione since analogue 14a showed the best affinity (IC50 = 5.2 microM); (b) the GST G site is not able to accommodate a chain length elongation of one methylene group (no affinity for analogues 14c,f); (c) a one-methylene group chain length reduction is tolerated, much more for the "Glu side" (14d, IC50 = 10.1 microM) than for the "Gly side" (14b, IC50 = 1800 microM); (d) the mercaptomethyl group must remain at position 5 as shown from the null affinity of the 6-mercaptomethyl analogue 14e; (e) the additional peptide isosteric E double bond (25) or hydroxyl derivative (23) in 14e did not help to retrieve affinity. This work reveals useful information for the design of new selective nonpeptidic and peptidase-stable glutathione analogues.

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Is Through-Bond Dihydroaromaticity Attainable? Preparation of [4,5]Dihomotropone, Investigation of Its Ground-State Properties, and an Attempt to Generate the Dihomotropylium Cation

Cited by 13 publications

References 1 publication

Homoaromaticity

Homoaromaticity

Photoswitching neutral homoaromatic hydrocarbons

Synthesis and Glutathione S-Transferase Structure−Affinity Relationships of Nonpeptide and Peptidase-Stable Glutathione Analogues

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