19751-76-9Relevant articles and documents
Asymmetric Total Synthesis of (+)-Winchinine B
Liu, Zaimin,Ju, Xiaolin,Ma, Shiqiang,Du, Chenglong,Zhang, Weiwei,Li, Huilin,Wang, Xiaolei,Xie, Xingang,She, Xuegong
, p. 14994 - 15000 (2019)
The first asymmetric total synthesis of aspidosperma alkaloid (+)-winchinine B was achieved in 12 steps from commercially available materials. A new synthetic strategy which features an efficient aza-Michael addition, a ruthenium-catalyzed transfer dehydrogenation, and an intramolecular palladium-catalyzed oxidative coupling was adopted to install the ABC tricycle system. A one-pot process involving carbonyl reduction/iminium formation/intramolecular conjugate addition developed by our group was utilized to construct the D ring moiety.
Hemisynthesis of rhazinilam analogues: Structure - Activity relationships on tubulin-microtubule system
David, Bruno,Sevenet, Thierry,Thoison, Odile,Awang, Khalijah,Pais, Mary,Wright, Michel,Guenard, Daniel
, p. 2155 - 2158 (1997)
Semi-synthesis of derivatives of rhazinilam, an antitubulin compound, delineated some molecular features necessary for biological activity. In the course of this study, the formation of rhazinilam from 1,2-didehydroaspidospermidine is reexamined and a new mechanism is proposed.
Synthesis of Eburnamonine and Dehydroaspidospermidine
Wenkert, Ernest,Hudlicky, Tomas
, p. 1953 - 1957 (1988)
The route of synthesis of γ-imino carbonyl compounds by cyclopropanation of enamides and acid-catalyzed ring opening of the resultant β-amido cyclopropanecarboxylates has been applied to the preparation of substituted 1-piperideines and therefrom to the synthesis of the alkaloids eburnamonine, dehydroaspidospermidine, and aspidospermidine.
TiCl3-Mediated Synthesis of 2,3,3-Trisubstituted Indolenines: Total Synthesis of (+)-1,2-Dehydroaspidospermidine, (+)-Condyfoline, and (?)-Tubifoline
Delayre, Bastien,Piemontesi, Cyril,Wang, Qian,Zhu, Jieping
supporting information, p. 13990 - 13997 (2020/06/10)
2,3,3-Trisubstituted indolenine constitutes an integral part of many biologically important monoterpene indole alkaloids. We report herein an unprecedented access to this skeleton by a TiCl3-mediated reductive cyclization of tetrasubstituted alkenes bearing a 2-nitrophenyl substituent. The proof of concept is demonstrated firstly by accomplishing a concise total synthesis of (+)-1,2-dehydroaspidospermidine featuring a late-stage application of this key transformation. A sequence of reduction of nitroarene to nitrosoarene followed by 6π-electron-5-atom electrocyclization and a 1,2-alkyl shift of the resulting nitrone intermediate was proposed to account for the reaction outcome. A subsequent total synthesis of (+)-condyfoline not only illustrates the generality of the reaction, but also provides a mechanistic insight into the nature of the 1,2-alkyl shift. The exclusive formation of (+)-condyfoline indicates that the 1,2-alkyl migration follows a concerted Wagner–Meerwein pathway, rather than a stepwise retro-Mannich/Mannich reaction sequence. Conditions for almost quantitative conversion of (+)-condyfoline to (?)-tubifoline by way of a retro-Mannich/1,3-prototropy/transannular cyclization cascade are also documented.
