NOESY correlations used to establish the relative conformation in phorbaside A, and synthetic models (166–168) used for quantative CD comparison. (a) CD spectra of phorbaside A (12), 166, and ent–166. (b) CD spectra for 12, 167, and 168. Reproduced with permission from Skepper, C. K.; MacMillan, J. B.; Zhou, G-X.; Masuno, M. N.; Molinski, T. F. Chlorocyclopropane Macrolides from the Marine Sponge Phorbas sp. Assignment of the Configurations of Phorbasides A and B by Quantitative CD. J. Am. Chem. Soc. 2007, 129(14), 4150–4151. © 2007 American Chemical Society. (Ref. xvia.