General Approach to the Total Synthesis of 9-Methoxy-Substituted Indole Alkaloids: Synthesis of Mitragynine, as well as 9-Methoxygeissoschizol and 9-Methoxy-<i>N</i><sub>b</sub>-methylgeissoschizol
作者:Jun Ma、Wenyuan Yin、Hao Zhou、Xuebin Liao、James M. Cook
DOI:10.1021/jo801839t
日期:2009.1.2
Herein, the full details of the synthesis of the 9-methoxy-substituted Corynanthe indole alkaloids mitragynine (1), 9-methoxygeissoschizol (3), and 9-methoxy-Nb-methylgeissoschizol (4) are described. Initially, an efficient synthetic route to the optically active 4-methoxytryptophan ethyl ester 20 on a multigram scale was developed via a Mori−Ban−Hegedus indolesynthesis. The ethyl ester of d-4-methoxytryptophan
Total Synthesis of (+)-Yohimbine via an Enantioselective Organocatalytic Pictet–Spengler Reaction
作者:Bart Herlé、Martin J. Wanner、Jan H. van Maarseveen、Henk Hiemstra
DOI:10.1021/jo201657n
日期:2011.11.4
Diels–Alder reaction of the type earlier reported by Jacobsen. These two key steps constitute the basis for a nine-step total synthesis of (+)-yohimbine from tryptamine. A similar asymmetric Pictet–Spengler reaction was applied to the synthesis of an intermediate in the recent total synthesis of corynantheidine by Sato.
Enantioselective Syntheses of Corynanthe Alkaloids by Chiral Brønsted Acid and Palladium Catalysis
作者:Martin J. Wanner、Elise Claveau、Jan H. van Maarseveen、Henk Hiemstra
DOI:10.1002/chem.201103150
日期:2011.12.2
Synergistic catalysis: Three indole alkaloids (−)‐corynantheidine, (+)‐corynantheine and (+)‐dihydro‐corynantheine were prepared following a short and common strategy based on the binol phosphoric acid catalyzed enantioselective Pictet–Spengler reaction, followed by closure of the final ring by an intramolecular Tsuji–Trost‐type Pd‐catalyzed allylic alkylation by using an α‐ketoester‐derived enolate
Total Synthesis of the Opioid Agonistic Indole Alkaloid Mitragynine and the First Total Syntheses of 9-Methoxygeissoschizol and 9-Methoxy-<i>N</i><sub>b</sub>-methylgeissoschizol
作者:Jun Ma、Wenyuan Yin、Hao Zhou、James M. Cook
DOI:10.1021/ol071220l
日期:2007.8.1
An enantiospecific method for the synthesis of 4-methoxytryptophan has been developed via a regiospecific Larock heteroannulation and employed for the firsttotalsyntheses of 9-methoxygeissoschizol and 9-methoxy-Nb-methylgeissoschizol, as well as the totalsynthesis of the opioid agonistic alkaloid mitragynine. The asymmetric Pictet-Spengler reaction and a Ni(COD)2-mediated cyclization served as key
The Double-Bond Configuration of Corynanthean Alkaloids and Its Impact on Monoterpenoid Indole Alkaloid Biosynthesis
作者:Ruben Eckermann、Tanja Gaich
DOI:10.1002/chem.201505068
日期:2016.4.11
incorporate E or Z double bonds located at C19–C20, the alkaloids downstream in the biosynthesis exclusively exhibit the E doublebond. This study shows that secondary cyclizations preferentially occur with the E isomer of geissoschizine or its derivatives. This is attributed to the flexibility of the quinolizidine system of the corynanthean alkaloids, which can adopt a cis or trans conformation. For