Expedient construction of the ABEF azatetracyclic ring systems of lycoctonine-type and 7,17-seco-type C₁₉-diterpenoid alkaloids.
A synthetic strategy for the modeling construction of the highly bridged azatetracyclic ABEF ring system of numerous lycoctonine-type C19-diterpenoid alkaloids bearing a characteristic oxygenated quaternary center at C-7 has been successfully developed. The tetracyclic core was constructed rapidly from a readily prepared 6,7-bicyclic AB ring precursor through a 13-step sequence via an advanced tetracyclic N,O-acetal intermediate, which belong to another core structure of natural 7,17-seco-type alkaloids. The key step involves an SmI2-promoted intramolecular radical coupling reaction of an N,O-acetal with a carbonyl group, mimicking a plausible biogenetic transformation.
Key Laboratory of Drug Targeting and Drug Delivery Systems of the Ministry of Education, Department of Chemistry of Medicinal Natural Products, West China School of Pharmacy, and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University , Chengdu 610041, China.
Hang
H
Cheng
Fan-Hao
FH
Zeng
Ding
D
Ma
Min-Li
ML
Jiang
Liang
L
Xu
Feng-Peng
FP
Wang
D000157:Aconitine / Q000031:analogs & derivatives* / Q000737:chemistry; D000470:Alkaloids / Q000737:chemistry*; D004224:Diterpenes / Q000737:chemistry*; D006576:Heterocyclic Compounds, 4 or More Rings / Q000737:chemistry*; D015394:Molecular Structure
D000470:Alkaloids; D004224:Diterpenes; D006576:Heterocyclic Compounds, 4 or More Rings; C093992:lycoctonine; D000157:Aconitine