An approach to the pentacyclic core of aspidophylline A is described. The strategy features CAN-mediated intramolecular azidoalkoxylation of enecarbamate and ruthenium-catalyzed atom transfer cyclization.
Divergent Enantioselective Synthesis of (−)-Galanthamine and (−)-Morphine
作者:Barry M. Trost、Weiping Tang、F. Dean Toste
DOI:10.1021/ja054449+
日期:2005.10.1
tricyclic intermediate is available in six steps from 2-bromovanillin and the monoester of methyl 6-hydroxycyclohexene-1-carboxylate. This intermediate requires only two steps to convert to (-)-galanthamine. Using a Heck vinylation, we found that the fourth ring of codeine/morphine could be formed. The final ring formation involves a novel visible light-promoted hydroamination. Thus, six steps are required
Stereocontrolled synthesis of complex polycycles using tetrathiafulvalene mediated radical-polar crossover reactions
作者:Rodney J. Fletcher、D. E. Hibbs、M. Hursthouse、Christopher Lampard、John A. Murphy、Stephen J. Roome
DOI:10.1039/cc9960000739
日期:——
Tetracyclic heterocycles are prepared in a stereocontrolled manner using radical-polar crossover chemistry.
四环杂环化合物通过自由基-极性交叉化学以立体控制的方式制备。
Stereoselective preparation of the ABCE tetracycle of aspidospermidine and related alkaloids
作者:Murat Kizil、John A. Murphy
DOI:10.1039/c39950001409
日期:——
Tandem radical cyclisation affords Stereoselective access to the ABCE tetracyclic substructure of aspidospermidine and related alkaloids.
串联自由基环化技术可立体选择性地获得阿司匹南苷和相关生物碱的 ABCE 四环亚结构。
Tandem Radical Cyclizations on Iodoaryl Azides: Synthesis of the Core Tetracycle of <i>Aspidosperma</i> Alkaloids
作者:Murat Kizil、Balaram Patro、Owen Callaghan、John A. Murphy、Michael B. Hursthouse、Dai Hibbs
DOI:10.1021/jo990891x
日期:1999.10.1
A new stereoselective approach to the tetracyclic core of Aspidosperma, alkaloids is described. Selective attack by tristrimethylsilylsilyl radicals on the aryl carbon-iodine bond of iodoaryl azides was first demonstrated on the simple model 15, thus both extending the recent discoveries of Kim and co-workers on aliphatic C-I bonds and demonstrating that the selectivity can be exploited in cascade radical cyclizations. Extension to the more complex substrate 25 afforded the core ABCE tetracyclic skeleton of the alkaloids in excellent yield and with efficient control of relative stereochemistry.
Fletcher, Rodney; Kizil, Murat; Lampard, Christopher, Journal of the Chemical Society. Perkin transactions I, 1998, # 15, p. 2341 - 2351
作者:Fletcher, Rodney、Kizil, Murat、Lampard, Christopher、Murphy, John A.、Roome, Stephen J.