Cyclooctatetraenoquinones. I The synthesis and structure of dibenzo[<i>a</i>,<i>e</i>]cyclooctene-5,6-dione

Yates, Peter; Lewars, Errol G.; McCabe, P. H.

doi:10.1139/v70-128

Cited by 15 publications

(8 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In an earlier paper in this series (2) we discussed the interest underlying the chemistry of 1,2-cyclooctatetraenoquinone (1) and its 1,4 isomer as a result of their potential aromaticity. We described a synthesis of dibenzo[a,e]cyclooctene-5,6-diene (2), the dibenzo analogue of 1, and demonstrated that its eight-membered ring is not aromatic.…”

mentioning

confidence: 99%

cis-5-Cyclooctene-1,2-dione and its Ethylene Ketals

Yates¹,

Lewars²,

McCabe³

1972

Can. J. Chem.

Self Cite

View full text Add to dashboard Cite

Oxidation of cis-cis-1,s-cyclooctadiene with hydrogen peroxide gives cis-5-cyclooctene-trans-l,2-diol (3) which is converted to cis-5-cyclooctene-l,2-dione (6) on treatment with dimethyl sulfoxide and acetic anhydride. Bromination of 6 is accompanied by transannular bonding to give a dibromo keto ether 9a or b. Ketalization of 6 with ethylene glycol gives a monoketal 11 and two diketals 12 and 13 with 1,3-dioxolane and 1,4-dioxane rings, respectively. Bromination of 12 with bromine or pyridinium perbromide is accompanied by transannular bonding and fission of one of the 1.3-dioxolane rings to give a dibromo monoketal ether 15a (or b). Bromination of 12 with N-bromosuccinimide followed by dehydrobromination gives a cyclooctadiene-l,2-dione diketal20a (or b).L'oxydation par l'eau oxygCnCe du cyclooctadi6ne-1.5 cis-cis donne le cis-cyclooct6ne-5 diol-1,2 trans (3) qui est converti en cis-cyclooctitne-5 dione-1,2 (6) par traitement avec le dimCthylsulfoxyde et l'anhydride acetique. La bromation de 6 est suivie de la formation d'une liaison transannulaire pour conduire au dibromocetoether 9a ou b. La cetalisation de 6 avec l'ethyl6neglycol donne un monocetal 11 et deux dicetals 12 et 13 avec respectivement des cycles dioxolane-1,3 et dioxane-1,4. La bromation de 12 par le brome ou par le perbromure de pyridinium est suivie de la formation d'une liaison transannulaire et de la scission d'un des cycles dioxolane-1,3 pour donner un dibromo monocetalether 15a (ou b). La bromation de 12 par le Nbromosuccinimide suivie d'une dthydrobromation, conduit au cyclooctaditne dione-1,2 dicetal 20a (ou b).Canadian Journal of Chemistry, 50, 1548Chemistry, 50, (1972 In an earlier paper in this series (2) we discussed the interest underlying the chemistry of 1,2-cyclooctatetraenoquinone (1) and its 1,4 isomer as a result of their potential aromaticity. We described a synthesis of dibenzo[a,e]cyclooctene-5,6-diene (2), the dibenzo analogue of 1, and demonstrated that its eight-membered ring is not aromatic. It was pointed out that the latter observation could not be taken as implying the absence of aromaticity in the parent monocyclic compound 1, since the benzenoid rings of 2 might damp the aromaticity of the eightmembered ring (3). We report now on some synthetic approaches to 1, which, although not crowned with success, have provided results of interest in the area of eight-membered ring chemistry.Oxidation of cis-cis-1,5-cyclooctadiene with hydrogen peroxide and formic acid followed by basic hydrolysis gave cis-5-cyclooctene-trans- 1,2-diol (3) as a colorless oil in 55% yield. The stereochemistry is assigned as trans on the basis of analogy with analogous hydroxylation reactions (4). The preparation of this diol by hydrolysis of the corresponding epoxide has been reported previously in the patent literature (5) and in a review (6). The diol afforded an oily diacetate (4) and a crystalline dibrosylate (5); the spectra of 3-5 were in full accord with these structural assignments (see Experimental).Oxidation of 3 with dimethyl sulfo...

show abstract

mentioning

confidence: 99%

cis-5-Cyclooctene-1,2-dione and its Ethylene Ketals

Yates¹,

Lewars²,

McCabe³

1972

Can. J. Chem.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Yates and co-workers (73) were successful in preparing dibenzocyclooctatrienedione However, the diketone was…”

Section: Ox 33mentioning

confidence: 99%

Studies in valence isomerism of unsaturated paramagnetic species

Goettert

View full text Add to dashboard Cite

“…In practice, a multigram synthesis of this compound was achieved from abundantly available (>100 g scale) dibromide 4 . Addition of AgOTs in the previously reported Kornblum oxidation of 4 to diketone 5 doubled the yield of this reaction and proved essential to the overall scalability of the synthesis. Me2 dbCOT 3 a and Ph2 dbCOT 3 b were then targeted for the present study to cover stereoelectronic diversity in catalysis.…”

Section: Figurementioning

confidence: 99%

“…[14] Herein, we report the development of ap racticala pproach to the synthesis and chiral resolution of 5,11-dbCOTd erivatives illustrated by Me2 dbCOT 3a [15] and Ph2 dbCOT 3b.B oth compounds proved to be readily resolvedb yb oth chromatographic and crystallization techniques which grants accesst og ramquantities of these compounds. [18] Addition of AgOTsi nt he previously reported Kornblum oxidation of 4 to diketone 5 [19] doubled the yield of this reaction and provede ssential to the overall scalability of the synthesis. As catalysts, these perform excellently in asymmetric catalysis, to readily providee nantioselectivities of up to > 99 % ee.…”

mentioning

confidence: 99%

Control of Enantioselectivity in Rhodium(I) Catalysis by Planar Chiral Dibenzo[a,e]cyclooctatetraenes

Melcher

Ivšić

Olagnon

et al. 2017

Chemistry A European J

View full text Add to dashboard Cite

Planar chiral 5,11-disubstiuted dibenzo[a,e]cyclo-octatetraenes (dbCOTs) have been developed as the first useful chiral homologs to dbCOT-ligands for asymmetric applications. Methods enabling the preparation of such compounds on a gram-scale in enantiomerically pure form are described. Evaluated as ligands in rhodium(I)-catalyzed 1,4- and 1,2-arylation reactions, tertiary and quarternary stereogenic centers were formed with excellent yields and selectivities of up to >99 % ee. A catalytic asymmetric synthesis of a key cyclization precursor to (-)-penifulvin A highlights the system in an applied context.

show abstract

Cyclooctatetraenoquinones. I The synthesis and structure of dibenzo[a,e]cyclooctene-5,6-dione

Cited by 15 publications

References 6 publications

cis-5-Cyclooctene-1,2-dione and its Ethylene Ketals

cis-5-Cyclooctene-1,2-dione and its Ethylene Ketals

Studies in valence isomerism of unsaturated paramagnetic species

Control of Enantioselectivity in Rhodium(I) Catalysis by Planar Chiral Dibenzo[a,e]cyclooctatetraenes

Contact Info

Product

Resources

About