Studies on the structure of the sesquiterpene caespitenone isolated from Porella species of liverwort

Abstract

Models of caespitenone, previously isolated from the liverwort Porella caespitans var. setigera, have been synthesized and their spectral data compared with those of this natural product. The discrepancy between these data prompted us to investigate the Colombian liverwort Porella swartziana, from which this compound was isolated and its structure has been revised by extensive 2D NMR techniques and chemical transformations to establish an africanane-type skeleton. The absolute configuration has also been determined.