𝔖 Bobbio Scriptorium
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1,9-Dimetalated ß-carbolines. Versatile building blocks for the total synthesis of Alkaloids

✍ Scribed by Franz Bracher; Dirk Hildebrand

Book ID
104204830
Publisher
Elsevier Science
Year
1994
Tongue
French
Weight
496 KB
Volume
50
Category
Article
ISSN
0040-4020

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✦ Synopsis

Reactions of the dimetalatcd B-carbolme 6, prepared ftom 1-bromo-Rcarbolme (4), witb electrophiles are. key steps in the syntheses of various &carboline alkaloids. Tmnmxtalation of 6 with ZnCl, followed by palladium-catalyzed CTOSS coupling reaction with Z-chlomquinolme gave the alkaloid nitmmarine (14).

l-Substituted 8-carbolines 1 represent a large class of biologically active alkaloids*. The classical approaches to &carbolmes (Bischler/Napieralski3, Pictet@engler4) suffer from the lack of convergence, since the group "R" is introduced into the molecule aheady in the first step of the reaction sequence. Very recently, we worked out a convergent strategy for the synthesis of 8-carbolme alkaloids via palladium-catalyzed cross coupling reactions of 1-chloro-Rcarboline (2) with various organometallic compoundss'6 (scheme 1). Thus, compounds of type 1 can be prepared conveniently by reaction of a preformed 8-carboline unit 2 with mcleophiles. d = H/COOH T I) I)N N H 1 R-Met cat. Pd 4 (ref. 5) Scheme 1 12329

📜 SIMILAR VOLUMES

β-Carboline alkaloids 9 [1]. Total synth
β-Carboline alkaloids 9 [1]. Total synthesis of the β-carboline alkaloids arenarine A and (±)arenarine B
✍ Franz Bracher; Andreas Puzik 📂 Article 📅 2004 🏛 Journal of Heterocyclic Chemistry 🌐 English ⚖ 128 KB 👁 1 views

## Abstract The first total synthesis of the β‐carboline alkaloids arenarine A **(1)** and arenarine B **(2)** is described. Methanolysis of the α‐bromoketone **9** gives **1** in good yield. Alternatively **1** can be obtained from the diazoketone **11** with boron trifluoride/methanol in poor yie