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An efficient synthetic approach to access (indol-3-yl)ethane-1,2-diamines with a protecting group at the indole N atom from readily available 3-(2-nitrovinyl)indoles is reported. This approach includes solvent-free conjugate addition of O-pivaloylhydroxylamines to 1-Boc-3-(2-nitrovinyl)indoles followed by mild reduction of the adducts. The obtained (indol-3-yl)ethane-1,2-diamines are convenient synthetic precursors for several classes of marine alkaloids. The first total synthesis of racemic topsentin C, a secondary metabolite from Hexadella sp., based on this approach is reported. The initially proposed structure for topsentin C has been revised.

Chemical investigation of the secondary metabolites of a rare New Zealand deep-sea sponge, Lamellomorpha strongylata, resulted in the isolation of twenty-one indole alkaloids, including two new bisindoles—(Z)-coscinamide D (1), (E)-coscinamide D (2)—and four compounds isolated for the first time as natural products—lamellomorphamides A (3), B (4), C (5) and D (6). In addition, fifteen previously reported natural products were isolated, seven of which are seco analogs of hamacanthin alkaloids. The one sponge produces enantiomerically pure but opposite configurations of compounds that only differ in the number of bromines, suggesting enantiodivergent biosynthesis. In addition, four compounds were isolated as partial racemates, suggesting these compounds are biosynthesized via two independent routes.

Chemical investigation of the secondary metabolites of a rare New Zealand deep-sea sponge, Lamellomorpha strongylata, resulted in the isolation of twenty-one indole alkaloids, including two new bisindoles&mdash, (Z)-coscinamide D (1), (E)-coscinamide D (2)&mdash, and four compounds isolated for the first time as natural products&mdash, lamellomorphamides A (3), B (4), C (5) and D (6). In addition, fifteen previously reported natural products were isolated, seven of which are seco analogs of hamacanthin alkaloids. The one sponge produces enantiomerically pure but opposite configurations of compounds that only differ in the number of bromines, suggesting enantiodivergent biosynthesis. In addition, four compounds were isolated as partial racemates, suggesting these compounds are biosynthesized via two independent routes.