Short syntheses of the indole alkaloids alocasin A, scalaridine A, and hyrtinadine A-B
作者:Nurul H. Ansari、Björn C.G. Söderberg
DOI:10.1016/j.tet.2016.05.057
日期:2016.7
Expedient syntheses of the indole alkaloids alocasin A, scalaridine A, and hyrtinadine A-B are presented. All four natural products contain one or two 5-hydroxyindolyl units. Three palladium catalyzed reactions, an alkyne hydrostannylation, a Kosugi-Migita-Stille cross coupling and a reductive N-heterocyclization are the key steps in the syntheses.
Concise Syntheses of Marine (Bis)indole Alkaloids Meridianin C, D, F, and G and Scalaridine A via One-Pot Masuda Borylation-Suzuki Coupling Sequence
作者:Marco Kruppa、Gereon A. Sommer、Thomas J. J. Müller
DOI:10.3390/molecules27072233
日期:——
with (di)azine halides in a sequentially Pd-catalyzed one-pot fashion, i.e., by Masuda borylation–Suzuki coupling (MBSC) sequence. This methodology was successfully applied to the concise syntheses of marine indole alkaloids meridianin C, D, F, and G, as well as to the bisindole alkaloid scalaridine A, which were obtained in moderate to excellent yield.
A synthesis of the pyridine-linked bisindole alkaloid scalaridine A is described. An iridium catalyzed, directed C-H borylation of N-Boc-5-methoxyindole gave the corresponding 3-borylindole, which underwent a one-pot, double Suzuki-Miyaura cross-coupling reaction with 3,5-dibromopyridine to install the entire heteroaromatic framework of the natural product. Removal of the protecting groups gave a synthetic sample of scalaridine A, which was spectroscopically identical to that described in the isolation report. (C) 2015 Elsevier Ltd. All rights reserved.