Synthesis of (−)-Pseudotabersonine, (−)-Pseudovincadifformine, and (+)-Coronaridine Enabled by Photoredox Catalysis in Flow
摘要:
Natural product modification with photo-redox catalysis allows for mild, chemoselective access to a wide array of related structures in complex areas of chemical space, providing the possibility for novel structural motifs as well as useful quantities of less abundant congeners. While amine additives have been used extensively as stoichiometric electron donors for photocatalysis, the controlled modification of amine substrates through single-electron oxidation is ideal for the synthesis and modification of alkaloids. Here, we report the conversion of the amine (+)-catharanthine into the natural products (-)-pseudotabersonine, (-)-pseudovincadifformine, and (+)-coronaridine utilizing visible light photoredox catalysis.
Identification of Indole Alkaloid Structural Units Important for Stimulus-Selective TRPM8 Inhibition: SAR Study of Naturally Occurring Iboga Derivatives
The iboga alkaloid voacangine (1) has been reported previously to be the first stimulus-selective TRPM8 antagonist. In the present report, a structure–activity relationship (SAR) study is described on the effects of some naturally occurring indole alkaloid analogues on TRPM8 inhibition. Dihydrocatharanthine (10) and catharanthine (11) were found to be inhibitors of TRPM8 activity, and their IC50 values
Biosynthetically Inspired Transformation of Iboga to Monomeric Post-iboga Alkaloids
作者:Sikwang Seong、Hyeonggeun Lim、Sunkyu Han
DOI:10.1016/j.chempr.2018.10.009
日期:2019.2
Organisms have evolved to produce various natural products from a common precursor as a means of maximizing the number of secondary metabolites, thus acquiring selectional advantages. By adopting nature's divergent biosynthetic strategy, we transformed (+)-catharanthine to various iboga and post-iboga alkaloids, including (-)-conodusine A, (+)-conodusines B and C, (-)-voatinggine, (-)-tabertinggine, and (+)-dippinine B. Well-orchestrated oxidations and reorganizations of catharanthine derivatives enabled chemical access to these natural products.