Some results obtained in the utilisation of quinones as philodiene

Lora‐Tamayo, M.

doi:10.1016/0040-4020(58)88002-3

Cited by 16 publications

(4 citation statements)

References 17 publications

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“…Wayne B. Manning,* Joseph E. Tomaszewski Received May 23,1977 Various 1-, 2-, 3-, and 4-substituted derivatives of benz[a]anthracene-7,12-dione (4) have been prepared by reaction of ring-substituted styrenes and 1,l-naphthoquinone (5) in the presence of chloranil. Comparative reactions done with and without chloranil demonstrated that chloranil had a positive effect upon the yield of the substituted benz[a]anthracene-7,12-diones.…”

Section: A General Synthesis Of 1- 2- 3- and 4-substituted Benz[ Amentioning

confidence: 99%

A general synthesis of 1-, 2-, 3-, and 4-substituted benz[a]anthracene-7,12-diones

Manning¹,

Tomaszewski²,

Muschik³

et al. 1977

J. Org. Chem.

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Synthesis of Substituted Benz(a]anthracene-7,12-diones Calcd for C16H1204, parent ion mle 268.073; found 268.071.Preparation of V. Into a pressure bottle was placed 0.09 g (0.43 mmol of III,25 mL of benzene, and a Teflon stirring bar. The solution was cooled to -78 "C and excess I was condensed in. The bottle was capped and the reaction flask was heated to 90 "C and stirred overnight. The flask was then cooled and vented and the solvent was removed under reduced pressure. The crude product was dissolved in 5 mL of hexane and poured into a column of alumina. Elution with hexane removed butadiene polymer. This wm followed by elution with 15% EtOAc/hexane to move the desired product from the column. The eluent was evaporated to yield 0.10 g (90%) of V (greenish crystals), whose spectral (UV, NMR) properties were identical with those of an authentic sample (Aldrich), mp 165-166 "C (lit. mp 166-167 "C).4 2-Methoxy-V was prepared as above by the reaction of 0.10 g (0.42 mmol) of 6-methoxy-111 and excess 9.7 g (200 mmol) of I to yield 0.11 g (91%) of V (yellow crystals), mp 195 "C (lit. mp 200 0C):28 NMR 6 9.2 (d, 1 H, J = 4 Hz), 8.3-8.0 (m, 4 H), 7.8-7.65 (m, 3 H), 7.3 (d, 1 H, J = 4 Hz), 4.0 (s, 3 H); IR, C=O 1670 cm-', C=C 1625; UV 2236 %, (e 1.93 X lo"), 2555 (1.71 X lo"), 2903 (9.5 X lo3), 3010 (8.25 X lo3), 44083-Methoxy-V was prepared as above by the reaction of 0.05 g (0.21 mmol) of 7-methoxy-I11 and excess 9.7 g (200 mmol) of I to yield 0.045 g (75%) of 3-methoxy-V (yellow crystals), mp 145 "C: NMR 6 9.5 (d, 1 H, J = 10 Hz), 8.3-7.9 (m, 4 h), 7.75-7.6 (m, 2 H), 7.

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Section: A General Synthesis Of 1- 2- 3- and 4-substituted Benz[ Amentioning

confidence: 99%

A general synthesis of 1-, 2-, 3-, and 4-substituted benz[a]anthracene-7,12-diones

Manning¹,

Tomaszewski²,

Muschik³

et al. 1977

J. Org. Chem.

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“…We have found recently that reactions of various styrenyl systems 1 with 1,4-benzoquinones 2 / 3 are extraordinarily versatile processes, producing a variety of chiral cycloaddition products . In addition to products of Diels−Alder reaction found under thermal conditions, Lewis acid-promoted reactions give up to three different types of products, 5 − 10 (Scheme ). , The latter three types of products significantly extend the synthetic utility of quinone−styrene reactions, which have since been used to access racemic mixtures of a number of chiral biologically active natural products . Products 5 − 10 are obtained in Ti(IV)-promoted reactions of 1 with 2 / 3 , with mixtures of TiCl 4 and Ti(O i -Pr) 4 generally the most effective promoters.…”

Section: Introductionmentioning

confidence: 99%

Asymmetric Reactions of 2-Methoxy-1,4-benzoquinones with Styrenyl Systems: Enantioselective Syntheses of 8-Aryl-3-methoxybicyclo[4.2.0]oct-3-en-2,5-diones, 7-Aryl-3-hydroxybicyclo[3.2.1]oct-3-en-2,8-diones, 2-Aryl-6-methoxy-2,3-dihydrobenzofuran-5-ols, and Pterocarpans

et al. 1999

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Reactions of 2-methoxy-1,4-benzoquinones 2 and 3 with (E)-propenylbenzenes 1 promoted at −78 °C by Ti(IV)−TADDOLates prepared from diol-(+)-4 afford (1R,6R,7R,8R)-8-aryl-3-methoxy-7-methylbicyclo[4.2.0]oct-3-en-2,5-diones 5/8 or (1R,5R,6R,7R)-7-aryl-3-hydroxy-6-methylbicyclo[3.2.1]oct-3-en-2,8-diones 7/10 in good yield and high ee. (2S,3S)-2-Aryl-6-methoxy-3-methyl-2,3-dihydrobenzofuran-5-ols 6/9 are also found, but in slightly lower ee. Cyclobutanes 5/8 cleanly and efficiently rearrange to the dihydrobenzofurans 6/9 without loss of enantiomeric purity upon treatment with the Ti−TADDOLates at higher temperatures. Reactions of (Z)-propenylbenzene 17 and of indene with 2 and 3 give products in moderate enantiomeric purity. Products obtained from reactions of 1-anisylcycloalkenes with 2 differ significantly in yield and enantiomeric purity. In the latter reactions, the ee's of the cyclobutane products are consistently much higher than those of the dihydrobenzofuran products. More significantly, products of different absolute configuration result from different cycloalkenes. With 1-anisylcyclopentene or 1-anisylcyclohexene, all of the products are of similar configuration and are obtained in comparable yields and ee's. However, 1-anisylcycloheptene affords products that are diastereomeric with those of the 1-anisylcyclopentene, and in lower ee's. A mechanistic model is proposed. Application of these reactions to the enantioselective synthesis of the pterocarpan class of isoflavonoid natural products is also reported.

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“…Received May 23,1977 Various 1-, 2-, 3-, and 4-substituted derivatives of benz[o]anthracene-7,12-dione (4) have been prepared by reaction of ring-substituted styrenes and 1,4-naphthoquinone (5) in the presence of chloranil. Comparative reactions done with and without chloranil demonstrated that chloranil had a positive effect upon the yield of the substituted benz[o]anthracene-7,12-diones.…”

mentioning

confidence: 99%

Synthesis of 7,12-benz[a]anthraquinones via Diels-Alder reaction of 1,4-phenanthraquinones

Rosen¹,

Weber²

1977

J. Org. Chem.

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Some results obtained in the utilisation of quinones as philodiene

Cited by 16 publications

References 17 publications

A general synthesis of 1-, 2-, 3-, and 4-substituted benz[a]anthracene-7,12-diones

A general synthesis of 1-, 2-, 3-, and 4-substituted benz[a]anthracene-7,12-diones

Asymmetric Reactions of 2-Methoxy-1,4-benzoquinones with Styrenyl Systems: Enantioselective Syntheses of 8-Aryl-3-methoxybicyclo[4.2.0]oct-3-en-2,5-diones, 7-Aryl-3-hydroxybicyclo[3.2.1]oct-3-en-2,8-diones, 2-Aryl-6-methoxy-2,3-dihydrobenzofuran-5-ols, and Pterocarpans

Synthesis of 7,12-benz[a]anthraquinones via Diels-Alder reaction of 1,4-phenanthraquinones

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