Synthesis of Cycloprodigiosin Identifies the Natural Isolate as a Scalemic Mixture.
- Author(s): Johnson, Rebecca E
- de Rond, Tristan
- Lindsay, Vincent NG
- Keasling, Jay D
- Sarpong, Richmond
- et al.
Published Web Locationhttps://doi.org/10.1021/acs.orglett.5b01527
The enantiomers of the natural product cycloprodigiosin were prepared using an expedient five-step synthetic sequence that takes advantage of a Schöllkopf-Barton-Zard (SBZ) pyrrole annulation with a chiral isocyanoacetate and a nitrocyclohexene derivative. Using chiral HPLC and X-ray crystallographic analyses of the synthetically prepared material and natural isolate (isolated from the marine bacterium Pseudoalteromonas rubra), naturally occurring cycloprodigiosin was determined to be a scalemic mixture occurring in an enantiomeric ratio of 83:17 (R)/(S) at C4'.