Synthesis of Cyclogossine B Using a Traceless Pseudoproline Turn-Inducer

Michelle S. Y. Wong; Katrina A. Jolliffe

doi:10.1071/CH09643

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Synthesis of Cyclogossine B Using a Traceless Pseudoproline Turn-Inducer

Michelle S. Y. Wong ^A and Katrina A. Jolliffe ^A ^B

+ Author Affiliations

- Author Affiliations

^A School of Chemistry, The University of Sydney, NSW 2006, Australia.

^B Corresponding author. Email: jolliffe@chem.usyd.edu.au

Australian Journal of Chemistry 63(5) 797-801 https://doi.org/10.1071/CH09643
Submitted: 9 December 2009 Accepted: 9 February 2010 Published: 21 May 2010

Abstract

The first synthesis of the cyclic octapeptide, cyclogossine B, has been achieved, confirming the reported structure of this natural product. Cyclization of a linear precursor containing a cysteine-derived thiazolidine as a traceless turn-inducer occurred in significantly higher yields than cyclization of the analogous alanine-containing precursor under identical conditions. Deprotection of the thiazolidine followed by desulfurization provided cyclogossine B in good overall yield, indicating that cysteine-derived pseudoprolines can be effectively used as traceless turn-inducers to facilitate the cyclization of small peptides.

Acknowledgements

We thank the Australian Research Council for financial support and for the award of a Queen Elizabeth II research fellowship to K.A.J.

References

^* Numbering starts at the N-terminal Gly in the linear precursor.

^# Because of the hindered nature of the Xaa(Ψ^Me,Mepro) nitrogen, the heterocycles are normally incorporated into peptide chains as the preformed dipeptide.^[6] The cyclic nature of the pseudoproline prevents C-terminal epimerization.

Synthesis of Cyclogossine B Using a Traceless Pseudoproline Turn-Inducer

Abstract

Acknowledgements

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