In 1997, Crews and coworkers described the isolation, structure, and cytotoxicity of the cyclic peptide cyclocinamide A (CC-A). This and subsequent work proposed an all-S stereochemistry for this natural product. Previous synthetic work in a number of labs (including that of one of the present co-authors, JPK) prepared different stereoisomers of CC-A but none of these compounds corresponded to the natural product as determined by 1H and 13C NMR data. In this presentation, we report the assignment of the stereochemistry of cyclocinamide A as shown below (4S, 7R, 11R, 14S) through the application of of a DP4 analysis to this 14-membered, conformationally flexible, cyclic peptide with four unrelated stereocenters. In addition, we present the total synthesis of this isomer, thus verifying the DP4 prediction.

Assignment and synthesis of the the true structure of cyclocinamide A

256th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.