cis ‐Clerodane Diterpenes from the Liverwort Scapania ciliata

Chemical investigation of the Chinese liverwort Scapania ciliata led to the isolation of four new cis ‐clerodane lactones, named ciliatolides A–D ( 1 – 4 , resp.), among which compound 1 was found to be a tetranorclerodanoid. Their structures were determined by extensive analysis of spectroscopic data, and, in the case of compound 1 , together with a single‐crystal X‐ray diffraction analysis. The absolute configurations were established by analysis of the CD spectra and by quantum‐chemical CD calculations. The cytotoxicities of compounds 1 – 4 were preliminarily tested against the PC3 and MCF‐7 cell lines.