Thermal and Lewis acid promoted intramolecular Diels–Alder reaction of furanose tethered 1,3,9-decatriene systems: a synthetic and computational investigation
| Autor: | Prakash M. Bhate, Hanuman P. Kalmode, Dilip K. Maity |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
chemistry.chemical_classification
010405 organic chemistry Chemistry Stereochemistry General Chemical Engineering General Chemistry 010402 general chemistry Furanose 01 natural sciences Medicinal chemistry Transition state 0104 chemical sciences Adduct Intramolecular force Stereoselectivity Lewis acids and bases Isomerization Diels–Alder reaction |
| Zdroj: | RSC Advances. 6:63445-63462 |
| ISSN: | 2046-2069 |
| DOI: | 10.1039/c6ra10456h |
| Popis: | The intramolecular Diels–Alder (IMDA) reaction of furanose tethered 1,3,9-decatrienes (4a–4r) was investigated under thermal conditions and in the presence of a Lewis acid. The stereoselectivity was determined by establishing the structures of adducts through single crystal X-ray diffraction and 1H NMR spectroscopy. It was found that contrary to expectations, the thermal IMDA reaction of (3E) and (3Z)-1,3,9-decatrienes proceeded with nearly equal rate and furnished IMDA adducts (6–25) with moderate stereoselectivity. In some cases, rearranged products (9, 12, 17 and 24) arising out of a 1,5-sigmatropic shift, cis–trans isomerization followed by IMDA reaction were formed. In contrast, a Lewis acid promoted IMDA reaction afforded only one adduct albeit in lower yields. Not surprisingly, cis-boat transition states were favored over trans-boat transition states. Experimental results were corroborated with transition state modeling of these reactions by applying density functional theory based electronic structure calculations. |
| Databáze: | OpenAIRE |
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