Construction of the isocopalane skeleton: application of a desulfinylative 1,7-hydrogen atom transfer strategy
| Autor: | Xi-Bo Chen, Ying Han, Jiangmeng Ren, Xiong Xiao, Peiying Wu, Zhong-Yu Xu, Bu-Bing Zeng, Wen-Hao Ji, Qian-Ding Zeng |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
chemistry.chemical_classification
Allylic rearrangement Chemistry Organic Chemistry General Chemistry Nuclear magnetic resonance spectroscopy Hydrogen atom Ring (chemistry) Aldehyde Catalysis chemistry.chemical_compound Sulfonate Computational chemistry Intramolecular force Yield (chemistry) Organic chemistry |
| Zdroj: | Chemistry (Weinheim an der Bergstrasse, Germany). 21(23) |
| ISSN: | 1521-3765 |
| Popis: | Two attractive chirons, aldehyde 6 and chloride 7, exhibiting functionalized ent-spongiane-type tricyclic skeletons (ABC ring system), have been constructed and their absolute configurations have been studied by NMR spectroscopy and confirmed by single-crystal X-ray diffraction. Both of these chirons are derived from commercially available andrographolide in good yield. Aldehyde 6 is obtained through a novel K2 S2 O8 -catalyzed aquatic ring-closing reaction of allylic sodium sulfonate and intramolecular 1,7-hydrogen atom transfer process. Further mechanistic investigations demonstrate that the 1,7-hydrogen atom transfer is a free-radical process, whereby hydrogen migrates from C18 to C17, as evidenced by double-18- deuterium-labeled isotope experiments. Prospective applications of these two chiral sources are also discussed. |
| Databáze: | OpenAIRE |
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