Development of an Alkaloid-Pyrone Annulation: Synthesis of Pleiomaltinine
作者:Robert E. Ziegler、Shin-Jowl Tan、Toh-Seok Kam、John A. Porco
DOI:10.1002/anie.201204093
日期:2012.9.10
Odd Couple: A method for the synthesis of alkaloid‐pyrones using a novel pyrone annulation of β‐carbolines and indoles with 3‐siloxy‐4‐pyrones is reported. The approach has enabled synthesis of the unusual alkaloid‐pyrone pleiomaltinine from the plant‐derived indole‐alkaloid pleiocarpamine (see Scheme; TBS= tert‐butyldimethylsilyl).
Enantiospecific Synthesis of (-)-Alstonerine and (+)-Macroline as Well as a Partial Synthesis of (+)-Villalstonine
作者:Yingzhi Bi、Lin-Hua Zhang、Linda K. Hamaker、James M. Cook
DOI:10.1021/ja00099a021
日期:1994.10
The enantiospecific synthesis of (-)-alstonerine (5) and (+)-macroline (8), as well as a partial synthesis of the Alstonia bisindole alkaloid villalstonine (2) has been completed. In addition, a more stable macroline equivalent 9 was prepared. The stereochemistry at C(15) and C(16) in 5 and 8 has been successfully installed by a stereoselective Claisen rearrangement followed by stereospecific hydroboration-oxidation of the exocyclic methylene function at C-16. The E ring in alstonerine 5 was constructed by a regioselective cyclization followed by a novel Swern oxidation under modified conditions [(COCl)(2)/DMSO/CH2Cl2, -78 degrees C to -10 degrees C/1.5 h; Et(3)N], whereas the C(20)-C(21) enone system in macroline (8) was generated via a convenient one pot process from the beta-diol 45. Condensation of either synthetic (+)-macroline (8) or the macroline equivalent 9 with natural pleiocarpamine 7 in 0.2 N HCl furnished the antiamoebic, antimalarial bisindole alkaloid villalstonine 2. This constitutes the first partial synthesis of any of the Alstonia bisindoles from a synthetically derived indole moiety.
Biomimetic synthesis of the bisindole alkaloids villalstonine and alstonisidine
作者:David E. Burke、James M. Cook、P. W. Le Quesne
DOI:10.1021/ja00783a039
日期:1973.1
Enantiospecific Total Synthesis of (−)-Anhydromacrosalhine-methine and Partial Synthesis of the Antiamoebic Bisindole Alkaloid (−)-Macrocarpamine<sup>1</sup>
作者:Tong Gan、James M. Cook
DOI:10.1021/jo971570t
日期:1998.3.1
An enantiospecific total synthesis of (-)-anhydromacrosalhine-methine (7a) was completed from D-(+)-tryptophan via the asymmetric Pictet-Spengler reaction. In addition, a partial synthesis of (-)-anhydromacrosalhine-methine (7a) was carried out from the natural product (+)-ajmaline (10). The coupling reaction of plant-derived (+)-pleiocarpamine (8) with synthetic diene 7a provided the antiamoebic bisindole alkaloid (-)-macrocarpamine (1) in 75% yield. This sequence serves as the first example of the action of a nucleophile at [at C(2)] on a protonated form [C(3)] of pleiocarpamine 8 in the Alstonia series to provide a bisindole alkaloid.