# Synthesis of the I–K Fused Polyether Array of CTX3C and Related Ciguatoxins by Use of a Gold-Catalyzed Cyclization Reaction

## TL;DR

Scientists synthesized a complex part of the CTX3C toxin using a gold-catalyzed reaction, making it easier to study and understand.

## Contribution

A new gold-catalyzed cyclization method was developed for synthesizing a key part of ciguatoxins.

## Key findings

- The I–K fragment of CTX3C was synthesized from a chiral pool-derived alcohol.
- A gold-catalyzed cyclization efficiently formed ring K under mild conditions.
- The tricyclic fragment with a dimethyl-substituted side chain was successfully created.

## Abstract

The I–K fragment
(C31–C49) of the ciguatoxin CTX3C
has been synthesized from a simple chiral pool derived tetrahydropyranyl
alcohol. An efficient gold-catalyzed cyclization reaction of a γ′-hydroxy
ynone has been used to accomplish efficient closure of ring K under
mild conditions. The resulting vinylogous ester has been elaborated
to give a complete tricyclic fragment bearing the dimethyl-substituted
side chain required for assembly of the LM spirocyclic acetal portion
of the target.