Synthesis of new substituted dihydroheptalene derivatives: SiO2- and base-catalyzed rearrangement of dimethyl trans-3,8-dihydroheptalene-3,8-dicarboxylate

Date

2001-01-01

Author

Saracoglu, N
Menzek, A
Kinal, A
Balcı, Metin

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Dimethyl trans-3,8-dihydroheptalene-3,8-dicarboxylate (trans-3) isomerizes to dimethyl cis-3,8-dihydroheptalene-3,8-dicarboxylate (cis-3) upon treatment with SiO2. On the other hand, base-catalyzed reaction of trans-3 undergoes a direct 1,3-intramolecular proton shift to give 6 at room temperature in 5 min. Prolonged reaction time formed isomers 7 and 8 in a ratio of 4:1. AM1 calculations indicate that the isomer 8, which is formed as minor product, has a lower heat of formation (-99.34 kcal mol(1)) than that of the major isomer 7 (-92.05 kcal mol(1)). However, when a similar reaction was performed at 100 degreesC, the thermodynamically more stable isomer 8 was formed as the major product. Furthermore, cycloaddition reactions of these new dihydroheptalene derivatives 6 and 7 with different dienophiles have been studied. The mechanism has been discussed.

Subject Keywords

Dihydroheptalene, Cycloheptatriene-norcaradiene equilibrium, 1,3-hydrogen shift, Cycloaddition

URI

https://hdl.handle.net/11511/56718

Journal

CANADIAN JOURNAL OF CHEMISTRY-REVUE CANADIENNE DE CHIMIE

DOI

https://doi.org/10.1139/cjc-79-1-35

Collections

Graduate School of Natural and Applied Sciences, Article

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Citation Formats

N. Saracoglu, A. Menzek, A. Kinal, and M. Balcı, “Synthesis of new substituted dihydroheptalene derivatives: SiO2- and base-catalyzed rearrangement of dimethyl trans-3,8-dihydroheptalene-3,8-dicarboxylate,” CANADIAN JOURNAL OF CHEMISTRY-REVUE CANADIENNE DE CHIMIE, pp. 35–41, 2001, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/56718.