(+)-Kjellmanianone (l_), member of the cyclopentanoid class of antibiotics, was isolated in 1380 by Nakayama et al'--* from the brown algae, Sargassum kjellmanianum and shown to display moderate activity against such gram positive bacteria as c. _ coli Kl2 and Bacillus subtilis var. niger. The struc--ture, initially derived via chemical and spectroscopic methods, was confirmed by single crystal X-ray analysis, the latter providing in addition the absolute ...