Sheng Liu

Two sets of starting materials were tested to trigger domino processes involving C3 insertion of indole fragments and C-C migration, thereby enabling the synthesis of the specific bisindole framework with a central troponoid core related to caulersin. The reaction between bis(indolyl)methane and methyl bromopyruvate oxime under BF3.Et2O-mediated condition successfully delivered the desired product, whereas methyl 2-(hydroxyimino)-3-(1H-indol-3-yl)propanoate reacted with indole-3-carbinol to produce an unexpected cyclohept[1,2-b:5,4-b’]bisindole derivative.

Attempts to directly construct bisindole alkaloids caulerpin and caulersin resulted in the discovery of novel synthetic approaches to caulersin and an unexpected product—racemosin B.

This study presents a a straightforward synthetic approach to the specific pentacyclic bisindole structures related to fascaplysin alkaloids. The key transformation is an acid-promoted cascade involving a C–N bond formation/Mannich-type cyclization/dehydrogenation sequence. Nineteen novel bisindole derivatives bearing a wide range of functional groups were prepared by this method.

An unsuccessful attempt to directly construct alkaloid iheyamine A from a fascaplysin framework resulted in the discovery of a novel synthetic approach to alkylated δ,γ-biscarboline derivatives.

Specific carbazolelactams represent the basic framework of structurally and biologically significant calothrixin alkaloids that were produced according to a novel two-pot sequence.

An efficient and biomimetic synthetic approach to 3,4-diindolylpyrrole-2,5-dicarboxylate derivatives, including lycogarubin C, lynamicin D and related analogues, was discovered.

The Pictet-Spengler reaction between tryptamine and (5-methoxy-2-nitrophenyl)-glyoxal in hot AcOH could trigger a redox-mediated cyclization and reduction sequence to form iheyamine A in 52% yield.