Palmadorins A-C, Diterpene Glycerides from the Antarctic Nudibranch Austrodoris kerguelenensis

The nudibranch Austrodoris kerguelenensis is distributed widely around the Antarctic coast and continental shelves. Earlier collections front McMurdo Sound and the Weddell Sea shelf have afforded it Suite of diterpene glyceride esters, a compound class implicated as a chemical defense in nudibranchs. The present chemical investigation of A. kerguelenensis collected near Palmer Station on the Western Antarctic Peninsula has revealed additional examples, palmadorins A-C (1-3), Lis the first three members of a new series of elerodane diterpenes. In this paper we describe their isolation, structure elucidation, and stereochemical analysis using a combination of one- and two-dimensional NMR spectroscopy and wet chemical methods.