6393-66-4Relevant articles and documents
Bioinspired Divergent Oxidative Cyclizations of Geissoschizine: Total Synthesis of (–)-17-nor-Excelsinidine, (+)-16-epi-Pleiocarpamine, (+)-16-Hydroxymethyl-Pleiocarpamine and (+)-Taberdivarine H
Jarret, Maxime,Tap, Aurélien,Turpin, Victor,Denizot, Natacha,Kouklovsky, Cyrille,Poupon, Erwan,Evanno, Laurent,Vincent, Guillaume
, p. 6340 - 6351 (2020/09/07)
We report a full account of our efforts towards bioinspired oxidative cyclizations of geissochizine and analogs to mimic the biosynthesis of the mavacuran, akuammilan, and excelsinidine groups of monoterpene indole alkaloids. The construction of the A,B,C,D ring system of geissoschizine was first achieved by merging two known syntheses of this alkaloid. Modified Ma's oxidative conditions (KHMDS/I2) applied directly to geissoschizine induced formation of the N4–C16 bond encountered in the excelsinidines core. Identical conditions applied to C16-dimethylmalonate-containing N4-quaternized substrates ended in the formation of the mavacurans core (N1–C16 bond). With this unified oxidative cyclization strategy: (–)-17-nor-excelsinidine, (+)-16-epi-pleiocarpamine, (+)-16-hydroxymethyl-pleiocarpamine, 16-formyl-pleiocarpamine and (+)-taberdivarine H were synthetized. We also report a shortened total synthesis of 16-epi-pleiocarpamine compared to our preliminary communication from a C16-monoester analog. Alternatively, 17-nor-excelsinidine was synthesized via an intramolecular nucleophilic substitution of a 7-membered ring α-chlorolactam prepared from 16-desformyl-geissoschizine.
Bioinspired Oxidative Cyclization of the Geissoschizine Skeleton for Enantioselective Total Synthesis of Mavacuran Alkaloids
Jarret, Maxime,Turpin, Victor,Tap, Aurélien,Gallard, Jean-Fran?ois,Kouklovsky, Cyrille,Poupon, Erwan,Vincent, Guillaume,Evanno, Laurent
, p. 9861 - 9865 (2019/07/04)
Reported is the enantioselective total syntheses of mavacuran alkaloids, (+)-taberdivarine H, (+)-16-hydroxymethyl-pleiocarpamine, and (+)-16-epi-pleiocarpamine, and their postulated biosynthetic precursor 16-formyl-pleiocarpamine. This family of monoterp
Die absolute Konfiguration von Macrolin, einem Abbauproduct des Alkaloides Villalstonin
Neukomm, Gisela,Kletzhaendler, Erika,Hesse, Manfred
, p. 90 - 96 (2007/10/02)
The absolute configuration of macroline (1), a degradation product of villalstonine (2), was determined.The chemical degradation of 1 gave a mixture of (-)-(20S)-20,21-hihydro-19-desoxo-macroline (9) and (-)-(20R)-20,21-dihydro-19-desoxo-macroline (10), which was related to the degradation products 9 of (+)-ajmaline (3) and 10 of (+)-isoajmaline (4) of known absolute configuration.Together with the complete relative stereochemistry of 2 the absolute configuration of 2 and of the second moiety of 2, (+)-pleiocarpamine (20), could be derived.Since the absolute configuration of the (-)-6,7-dihydroaspidospermidine moiety of (+)-pycnanthinine has been known already , the structure by Gorman et al. represents the absolute configuration of (+)-pycnanthinine.