Total Synthesis Blog

Do you know snowdrops? It’s well-known that bulbs of these flowers (latin name is Galanthus nivalis) contain many alkaloids and galantamine (or galanthamine) is one of them:

This is an important natural product because of its biological properties and phamacological applications – it’s used in treatment of mild Alzheimer’s disease. So there are many approaches to total synthesis of galantamine and here I’ll try to show most recent of them (I think so).

Authors of the paper on which I base developed new interesting reaction: DMCRC – what means Double Michael-Claisen Reaction Cascade. The reaction allows to synthesise quickly highly substituted cyclohexenones which can be used in total syntheses of many ’sterically congested’ natural products and galantamine is only one of several examples mentioned in paper (the others are aspidospermidone, lycoramine and  mesembrine).

Let’s look at retrosynthetic analysis:

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Today, some nice total synthesis – Barrenazines A and B. Structure of these C₂-symmetrical molecules is shown below:

These Barrenazines were isolated in 2003 by Kashman from some (according to authors of article) unidentified tunicates from Barren Islands (Madagascar). They exhibit mild cytotoxic activity against certain tumor cells. The retrosynthetic analysis is shown below:

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